Nummer 235 2006

KATHOLIEKE

UNIVERSITEIT

LEUVEN

THE IRONIC EFFECTS OF FOOD TEMPTATIONS ON SELF-CONTROL PERFORMANCE

FACULTEIT ECONOMISCHE EN TOEGEPASTE ECONOMISCHE WETENSCHAPPEN

Proefschrift voorgedragen

tot het behalen van de graad

van Doctor in de Toegepaste

Economische Wetenschappen

door

Kelly GEYSKENS

COMMITTEE

ADVISORS: Prof. Dr. Luk Warlop

Prof. Dr. Siegfried Dewitte

Prof. Dr. Marnik Dekimpe

Prof. Dr. Stijn van Osselaer

Prof. Dr. Brian Wansink

Daar de proefschriften in de reeks van de Faculteit Economische en Toegepaste

Economische Wetenschappen het persoonlijk werk zijn van hun auteurs, zijn alleen

deze laatsten daarvoor verantwoordelijk.

ACKNOWLEDGEMENTS

A lot that cannot be said is at times best expressed in the words: “Thank you”.

I truly give great thanks and gratitude to the countless number of persons who have

been my protectors and guides through the achievement of this dissertation which is

far beyond my own mentality and imagination.

First of all, I am especially grateful to my promoter, Prof. Dr. Luk Warlop, for

providing me with the opportunity to become a doctoral student in the first place and

for his careful mentoring at the crucial moments, his insightful comments which I

consider a priceless gift in my journey as a PhD researcher, and for his peculiar talent

for motivating me when I lost faith in my (sometimes too complicated) research by

reminding me that science is cool. Your patience, motivation, enthusiasm, and

immense knowledge make you a great mentor and I am very grateful that I had you as

my supervisor.

I would also like to express my sincerest appreciation for my co-promoter,

Prof. Dr. Siegfried Dewitte, for his generous interest in my research, his inexhaustible

enthusiasm and amazing ideas, and his capability for disentangling the simple truth

out of a seemingly impossible clutter. Most of all, I am sincerely grateful for all the

time and energy, without doubt significantly more than one would expect from a co-

promoter, he invested in me. Thank you very much!

Together, Luk and Siegfried taught me how to express thoughts into

scientifically legible writing and explicable presentations. Their complementary

manner of dealing with reviews was quite funny though efficient. Siegfried’s

enormous disappointment, near to depression, when a reject or less positive than

expected review came through the door was compensated by Luk’s way of

considering it in perspective, emphasizing that revisions are not always that bad as

they look at first sight.

I am also indebted to all the other members of my committee: Professors

Marnik Dekimpe, Stijn van Osselaer, and Brian Wansink. Marnik, I appreciated your

concern to link my research to the real world and your insightful questions. I want to

thank you for being part of my committee; it was a real pleasure and a great honor.

Stijn, I would like to thank you for carefully reading this thesis, for your constructive

critique, suggestions, and stimulating discussions which contributed greatly to its

improvements. Also thanks for spending lots of hours on the roads for each of my

seminars. Your time and generous collaboration ever remain invaluable. Brian, it was

a real honor to have you in my committee. Your interest for my research is deeply

appreciated.

Many thanks go to my colleagues at the marketing research group of the

K.U.Leuven for the ideas, of which I am sure they ended up somewhere in this thesis,

that came up during numerous, sometimes very tiring, sessions. A special word of

thanks goes to my ‘room-mates’ Caroline, and Gert. Thanks for being there when I

felt like a little chat and for putting up with me when I was stressed or in a bad mood.

Gert, you helped me to ‘chill out’ whenever things became too stressful. Caroline, you

helped me to relax during our ‘shopping trips’ and enjoyable conversations. There

never was a dull moment during the time we spent together in 04.141 and I would like

to thank you both for it!

The final words are reserved for my family and friends. I am deeply indepted

to my parents, Alida and Guido, who made it possible for me to study and supported

me in order to get me to this point in my life. You have shared much wisdom with me

and taught me the ways of the world. Without you both I would be nowhere, have no

goals in life, and no destination ahead of me. You gave me the strength to accomplish

and aim at many dreams. I think you are the greatest parents one could ever wish for!

I also want to say thank you to all the members of my amazing family, especially my

sister Anja, Benny, my Godfather Gerrit and aunt Christiane, Lene, Lidia, Marie-

Louisa, Nikki, Omer, Rudy, and Xim who were of great help by their ways of giving

and creating my confidence in myself, who have backed me up, given me support and

courage, and cheered me on.

At last but not least I would like to thank Stefan. Thank you for always being

there for me, for your support and your ever lasting patience. Especially thanks for

enduring the endless shop trips for shopping carts full of potato chips, M&Ms and

other experimental candy while being followed with other clients’ eyes. You are one

of my dreams that came true, and I hope you will accompany me in my aim to

accomplish all my and our other dreams. Without you, I could never have done this

and I think, in this way, you earned a piece of my PhD. I hope we will stay on the

same wavelength forever; I love you!

Financial support of the Fund for Scientific Research – Flanders Belgium and

Censydiam is gratefully acknowledged.

Kelly

Leuven, September 2006

CONTENTS

ACKOWLEDGEMENTS

CONTENTS

LIST OF FIGURES

INTRODUCTION .............................................................................................1

SOCIETAL FRAMEWORK _________________________________________________________ 1

DISSERTATION GOAL ____________________________________________________________ 2

WHAT IS A FOOD TEMPTATION?__________________________________________________ 3

SELF-CONTROL __________________________________________________________________ 3 Self-control failure .................................................................................................4

Self-control enhancement and overview of the manuscripts ....................................5

MANUSCRIPT I: THE BACKDOOR TO OVERCONSUMPTION: THE EFFECT OF ASSOCIATING ‘LOW-FAT’ FOOD WITH HEALTH.................11

ABSTRACT ___________________________________________________________________ 11

OBESITY AND FOOD MARKETING PRACTICES ___________________________________ 12

LOW-FAT PRODUCTS AND HEALTH REFERENCES________________________________ 12

TWO MECHANISMS OF BEHAVIORAL EFFECTS OF HEALTH ASSOCIATIONS: SELF-

CONTROL REINFORCEMENT VERSUS ASSIMILATION ____________________________ 14

STUDY 1 ___________________________________________________________________ 15 Method.................................................................................................................16

Results .................................................................................................................17

Discussion............................................................................................................18

STUDY 2 ___________________________________________________________________ 18 Method.................................................................................................................19

Results and discussion..........................................................................................20

GENERAL DISCUSSION __________________________________________________________ 21 Overview of the findings ......................................................................................21

Implications for Consumer Welfare and Public Policy..........................................22

Further Research and Limitations .........................................................................23

MANUSCRIPT II: TEMPT ME JUST A LITTLE BIT MORE. THE EFFECT OF FOOD TEMPTATION ACTIONABILITY ON GOAL ACTIVATION AND SUBSEQUENT CONSUMPTION ..................................................................25

ABSTRACT ___________________________________________________________________ 25

FOOD TEMPTATIONS MAY HURT RESISTANCE TO SUBSEQUENT FOOD

TEMPTATIONS __________________________________________________________________ 26

FOOD TEMPTATIONS MAY HELP RESISTANCE AGAINST SUBSEQUENT FOOD

TEMPTATIONS __________________________________________________________________ 28

HYPOTHESES ___________________________________________________________________ 29

STUDY 1 ___________________________________________________________________ 32

STUDY 1A ___________________________________________________________________ 33 Method.................................................................................................................33

Results and Discussion .........................................................................................34

STUDY 1B ___________________________________________________________________ 35 Method.................................................................................................................35

Results and Discussion .........................................................................................36

STUDY 2 ___________________________________________________________________ 37 Method.................................................................................................................37

Results and Discussion .........................................................................................38

STUDY 3 ___________________________________________________________________ 39

STUDY 3A ___________________________________________________________________ 40 Method.................................................................................................................40

Results and discussion..........................................................................................41

STUDY 3B ___________________________________________________________________ 43 Method.................................................................................................................43

Results and discussion..........................................................................................43

GENERAL DISCUSSION __________________________________________________________ 45

IMPLICATIONS AND FUTURE RESEARCH ________________________________________ 48

MANUSCRIPT III: DEFEAT TEMPTATIONS AND GROW IN SELF-CONTROL .....................................................................................................51

ABSTRACT ___________________________________________________________________ 51

THE SELF-CONTROL STRENGTH MODEL ________________________________________ 53

THE COGNITIVE CONTROL MODEL______________________________________________ 54

THE SELF-CONTROL STRENGTH MODEL AND THE COGNITIVE CONTROL MODEL 56 Cognitive control model predictions .....................................................................57

Self-control strength model predictions ................................................................57

THE CURRENT STUDY ___________________________________________________________ 57 Method.................................................................................................................59

Results and discussion..........................................................................................60

GENERAL DISCUSSION __________________________________________________________ 62 Theoretical Implications .......................................................................................62

Future research .....................................................................................................64

GENERAL DISCUSSION ..............................................................................65

SUMMARY OF THE FINDINGS ____________________________________________________ 65

IMPLICATIONS __________________________________________________________________ 67

FUTURE RESEARCH AND LIMITATIONS__________________________________________ 69 Health Primes and Low-fat Snack Products ..........................................................69

Actionable Food Temptations and the Critical Level ............................................71

Success in Overriding the Self-control Conflict ....................................................73

Low-fat Snack Products and the Critical Level .....................................................74

Similarity of Consecutive Food Temptations ........................................................75

Limitations ...........................................................................................................76

REFERENCES ..............................................................................................77

LIST OF FIGURES

FIGURE 1.1: Consumption at the taste test (Regular and Ambiguous Chips) as a

function of Frame (Neutral or Health); study 2.

FIGURE 2.1: Affective-cognitive framework adapted for threat detector.

FIGURE 2.2: Consumption as a function of temptation and convenience, study 3A,

with “NFT”: No Food Temptation, “NAFT”: Non-Actionable Food

Temptation and “DAFT”: Delayed Actionable Food Temptation.

FIGURE 2.3: Consumption as a function of temptation and scent, study 3B, with

“NFT”: No Food Temptation, “NAFT”: Non-Actionable Food

Temptation and “DAFT”: Delayed Actionable Food Temptation.

FIGURE 3.1: Self-control performance (standardized) as a function of the similarity

between the second task (high for the Taste test and low for the

Anagram) and preceding level of food temptation.

1

INTRODUCTION

SOCIETAL FRAMEWORK

“I saw few die of hunger; of eating, a hundred thousand.”

Benjamin Franklin

In spite of the negative personal consequences, the prevalence of obesity and

overweight has increased dramatically over the last few decades (Abelson and

Kennedy 2004), especially in Western countries (WHO 1998). For example, about 15

percent of the Belgian population (Bossuyt and Van Oyen 2002) and 22,5% of the

American population (Flegal, Carroll, Kucsmarski, and Johnson 1998) suffers from

obesitas. Moreover, nearly two out of three adults in the U.S. can be classified as

overweight (Must et al. 1999, USDA), and it has been estimated that some 300,000

deaths per year are attributable to obesity (Allison et al. 1999).

Besides genetic determinants (Aitman 2003; Dietz 1991; Stunkard et al. 1991),

the reason for this increase is clear—an excess of dietary energy intake over energy

expenditure (Centers for Disease Control and Prevention (CDCP), 2004). Societal

changes and worldwide nutrition trends (e.g., shifts towards less physically

demanding work, agricultural productivity, food subsidies, convenience-related

trends, increasingly sedentary lifestyles, more varied diets with a higher proportion of

fats, saturated fats, and sugars) have been identified as contributing to the problem

(Cutler, Glaeser, and Shapiro 2003; Mitka 2003; Paeratakul et al. 2003; Variyam

2002). Although the reduction in physical activity probably explains an important part

of the obesity epidemic, Cutler et al. (2003) argue that increased caloric intake

contributes more to the rise in obesity than reduced caloric expenditure.

Technological innovations have been identified as a primary indirect cause for the

increase in caloric intake. Indeed, these innovations have given rise to the mass

production and preparation of convenient ready-to-eat meals, which in turn have

supplanted food preparation at home. Moreover, the advances in food preparation

technology have allowed manufacturers to exploit economies of scale by producing

2

ready-to-eat foods centrally, which has lowered average cost and eventually reduced

the food prices (Cutler et al. 2003). Typically price reductions benefit consumer

welfare (e.g., Hausman and Leibtag 2005) but may harm consumer welfare in case

people have self-control problems for the particular product. In addition to decreased

prices, other market forces like increasing flavor variety (Raynor and Epstein 2001)

and availability (Tardoff 2002), growing serving sizes (Nielsen and Popkin 2003;

Wansink 1996), and more convenient eating opportunities (e.g., ready to eat meals

and eating in restaurants), are often cited as driving the obesity epidemic (Critser

2003; Nestle 2002).

DISSERTATION GOAL

It is clear that obesity is a problem in need of a solution, and overconsumption

seems one of the culprits. The notion that people sometimes behave impulsively (i.e.,

in a manner that does not serve their long-term interests) when they are faced with a

trade-off between short-term pleasure and long-term health deserves deeper

exploration. The inability to consciously control the eating behavior is often attributed

to a “weakness of will” or lack of self-control (Smith 2002). One possible route to

reduce overconsumption may then be to design strategies that prevent self-control

failure. Designing such solutions relies on understanding consumer behavior and the

factors that influence food consumption. More in particular, this dissertation aimed at

investigating whether self-control can be enhanced by environmental cues, such as

subtle cues, which occur in purchase- or consumption situations, in ads, … or prior

food temptations. The main contribution of this dissertation is a deeper insight in the

role of environmental cues in enhancing self-control of food consumption.

We begin, in the next section, with defining a food temptation. After this, we

deal with the self-control problem. This part is divided into two sections; the first

section deals with self-control failure whereas the second section reflects how self-

control can be improved. In the process an overview of the manuscripts will emerge.

3

WHAT IS A FOOD TEMPTATION?

What makes a luscious but caloric dessert a temptation? According to previous

literature (Carver and Scheier 1998; Miller 1951) the desire for a mouth-watering

dessert makes both the experience of the immediate desire (i.e., eat the dessert) and

the interfering alternative long-term goal (i.e., restrict food intake and be healthy)

salient. The conscious sensation of this conflict is what makes this temptation a

temptation (Fishbach, Friedman, and Kruglanski 2003; Hoch and Loewenstein 1991).

The cognizance of this conflict reflects a self-control problem (Ainslie 1992;

Loewenstein 1996; Metcalfe and Mischel 1999; Mischel 1974; Rachlin 1995; 1996;

1997) which often leads consumers to try to resist the temptation in order to act

according to their long-term goals (e.g., Baumeister, Heatherton, and Tice 1994;

Shallice and Burgess 1993).

SELF-CONTROL

“Many people place a premium on the attribute of self-control. Individuals who have

this capacity are able to stay on diets, carry through exercise regimens, show up to

work on time, and live within their means. Self-control is so desirable that most of us

complain that we do not have enough of it.”

Laibson, 1997

“Strength is the capacity to break a chocolate bar into four pieces with your bare

hands - and then eat just one of the pieces.”

Judith Viorst

Self-control exertion can take place in various ways, for example by focusing

attention on irrelevant stimuli and away from the temptation or by keeping attention

and interest focused on the task of resistance (Ainslie 1992; Metcalfe and Mischel

1999). However, a substantial body of literature (Baumeister et al. 1994; Carver and

Scheier 1998; Tice, Bratslavsky, and Baumeister 2001) has shown that, depending on

various situational and personality factors, consumers are sometimes able to resist a

particular temptation, whereas in other circumstances, they fail. We will start by

elaborating self-control failure, followed by a section indicating possible ways to

enhance self-control and how these were tested in the manuscripts.

4

Self-control failure

“I can resist everything except temptation.”

Oscar Wilde

Self-control is lost whenever the desire for a given immediate behavior (e.g.,

eating) is greater than the consumer’s willpower to achieve long-term goals (e.g.,

health, good looks) (Hoch and Loewenstein 1991; Loewenstein 1996; Metcalfe and

Mischel 1999). In other words, short-run cravings often prevent people from

accomplishing their long-term goals. For example, larger package sizes increase

consumption (Wansink 1996) and stockpiling accelerates the consumption rate of

convenience goods due to a higher salience of the food products (Chandon and

Wansink 2002). Also, external food cues like visual (e.g., seeing half a cake on a

counter) or aromatic prominence (e.g., the scent of cookies in a room) have been

shown to lead to self-control failure (Fedoroff, Polivy, and Herman 2003; Lambert

and Neal 1992; Painter, Wansink, and Hieggelke 2002; Schachter 1971; Shiv and

Fedorikhin 2002; Wansink 1994).

Moreover, the self-control process itself might, ironically, facilitate self-

control failure. By trying to resist food temptations, attention is focused on inhibitory

goals. Small distractions in the environment will draw attention away from these

inhibitory goals to the most salient cues available in the environment (Ward and

Mann 2000). The self-control process, in this case trying to avoid food, in fact keeps

food concepts activated because the system scans for threatening cues. For this

reason, trying to control food intake has been considered as "a low-grade popular

infection" (Polivy and Herman 1983). Trying not to think of food (Heatherton, Polivy,

and Herman 1990) results in a pre-occupation with food (Ogden 1995). The result is

that counter priming with food makes food the most salient cue (Wegner 1994).

Accordingly, through self-control exertion, distraction often leads to self-control

failure (i.e., increased consumption). Overeating through distraction is known as the

disinhibition effect. The disinhibitors can be cognitive or emotional. One cognitive

disinhibitor is the belief that a goal is not attainable anymore in a given period; e.g.,

an initial dietary violation leads to a continuation of eating because the dieting goal

5

can no longer be obtained for today (Herman and Mack 1975). Another cognitive

disinhibitor is the limitation of processing resources, which has been shown to

increase preference for affect-laden food (i.e., chocolate cake) over less affect-laden

food (i.e., fruit salad), at least for people with weak self-control capacity (Shiv and

Fedorikhin 1999). Disinhibitors can also be emotional; e.g., strong emotional states

like anxiety lead to overeating (Polivy, Herman, and McFarlane 1994), or

pharmacological; e.g., sedating and relaxing substances like alcohol might lead to

overeating because of the loss of self-control (Muraven, Collins, and Nienhaus 2002).

In other words, self-control can only be successful in a sustainable way to the extent

that the consumer manages to ‘unattend’ the food and maintain focus on the

achievement of long-term goals (Baumeister and Heatherton 1996).

Self-control enhancement and overview of the manuscripts

“We gain the strength of the temptation we resist.”

Ralph Waldo Emerson

The hot-cool framework and manuscript I.

A considerable amount of research (e.g., Fishbach et al. 2003; Gilbert et al.

2004; Metcalfe and Mischel 1999) suggests several ways for self-control

enhancement. According to the hot-cool framework (Metcalfe and Mischel 1999),

self-control can take place because the nodes of the hot system, which represent

emotional stimuli, can be connected to the nodes of the cool system, which represent

cognitive reasoning. In this way, the cool nodes can control the behavior that is

induced by the hot nodes by activating other connected cool nodes that lack hot

connections. This mechanism allows the cold system to override impulses originating

in the hot system. Applied to the field of food consumption, exposure to appealing

cookies may activate the hot node of craving for these cookies. If this hot node is in

some way connected to a cool node, like ‘do not eat them because you are on a diet’,

this node can activate other cool nodes like ‘resist the cookies and eat fruit’, ‘live

long’, ‘be healthy’. This activation of the interconnected network of cool nodes can

prevent the consumer from eating the cookies. This framework implies that activating

a concept that is related to a cool node may enhance self-control. First, priming of a

6

concept temporarily increases the probability that the concept will be reactivated

when associated cues are activated. This implies that the priming of a cool node

makes this cool node active such that activation of an associated hot node will very

likely result in the (re)activation of that particular primed cool node. Subsequently,

priming of a concept that is related to a cool node should activate a whole network of

related cool nodes, which should result in enhanced self-control. Such priming can

thus be crucial to enhance control. This implies that if consumers are primed with for

example the diet/health concept, the cool node representing food intake restriction

will be more easily activated when food is presented. In this way, the priming of

diet/health related concepts should enhance self-control. This raises the interesting

question whether low-fat labels (e.g., diet, light, but also pictures of slim women)

would enhance food intake control of snack products because they are often

associated with a long term goals such as health or weight maintenance.

In manuscript I, we tested whether subtle health references (i.e., health

primes), often associated with low-fat snack foods, indeed activate the health goal and

its associations in memory and in this way reinforce self-control (Metcalfe and

Mischel 1999). We focused on the effects of health associations on low-fat snack

products because health organizations want to stimulate the market penetration of

low-fat products to reduce overall caloric intake and in this way solve the obesity

problem. However, besides the possible self-control reinforcing effect of the health

references accompanying low-fat snack foods, these health references might also

affect the way the consumer perceives those products, which we assumed to be

ambiguous with respect to health (Wheeler and Petty 2001). Contrary to our first

conceptualization, low-fat labels may bias health perception, which may result in

assimilation effects (Stapel and Koomen 2001), making the ambiguous object (in this

case the low-fat chips) appear more compatible with the activated concept (in this

case health) than without the health references. This “assimilation” mechanism would

make consumers more vulnerable to ambiguous temptations because they appear less

threatening then they actually are. In two lab studies, we found no evidence for the

self-control reinforcing process at all, neither for the low-fat snack product nor for its

regular counterpart. Rather, we found that health references increased consumption of

the ambiguous food. For the unambiguous unhealthy counterpart, no effect of the

health references was found. This implies that priming of diet/health related concepts

7

is not an effective strategy to enhance self-control activation. For regular snack

products, subtle health references have no influence on the quantity consumed.

Moreover, health references increase consumption when they accompany low-fat

snack products.

The model of asymmetric associations and manuscript II.

The results in the first manuscript suggest that either the activation of cool

nodes seems to be inefficient for self-control enhancement or the low-fat labels are

not directly connected with cool nodes. A more efficient strategy to help consumers

control their food intake might be through direct exposure to hot, tempting stimuli.

The activation of hot nodes might in fact activate cool nodes (e.g., restraining food

intake), connected to the activated hot node (e.g., food cues), which could result in the

activation of an interconnected network of cool nodes that successfully enhances self-

control. Some recent findings indeed suggest that control might be initiated by the

mere exposure to tempting food stimuli (Fishbach et al. 2003). The model of

asymmetric associations between temptations and higher priority goals (Fishbach et

al. 2003) states that automatic associations can develop between goals that are active

at the same time. These connections between goals result in mutual facilitation or

mutual inhibition, depending on whether the goals are related or opposing. For

example, the goal of leading a healthy life can be achieved by the goal of wanting to

go swimming but it can be opposed by the goal of wanting to go out eating in

McDonald’s. In other words, temptations that threaten the achievement of important

long-term goals could activate these opposing long-term goals and in this way

facilitate self-regulation. The model is asymmetric, implying that temptations activate

inhibitory goals but the goals inhibit the temptations. This asymmetry in the model is

necessary because the link between temptation and goal is made in order to exert self-

control. Repeated attempts at self-control lead to frequent co-occurrence of a

temptation (a dessert) and a goal (having a slim body). For example, if a person does

not eat dessert because of the long-term goal of having a nice and thin body, which

implies dieting, the link between the dessert (the temptation) and dieting (the goal) is

made. This results in an asymmetric link between the cognitive representations of the

temptations and the cognitive representations of the goal in memory. Because of

many activations of this link, it can become overlearned, which implies that the

8

activation of the goals by (opposing) temptations could be relatively independent of

cognitive resources and even subliminal activation of the temptation could be

sufficient to activate the goal. Moreover, Fishbach et al. (2003) state that the direct

priming of the goal increases the awareness of the goal but does not enhance self-

control attempts, contrary to the hot-cool framework (Metcalfe and Mischel 1999) but

in line with the findings of manuscript I. On the other hand, Fishbach et al. (2003)

state that the priming of temptations activates a narrower set of self-control intentions,

which does enhance self-control.

In manuscript II, we investigated whether exposure to food temptations,

differing in actionability, enhances self-control. Indeed, we found that exposure to

food temptations activate their opposing goal (i.e., dieting), independent of the level

of actionability of the food temptation. Only, the activation of the opposing long-term

goal does not automatically result in self-control enhancement. The exposure to food

temptations needs to exceed a certain critical level (Gilbert et al. 2004) that makes the

food temptations threatening for the achievement of the long-term goal, in order to

eventuate in self-control enhancement. Self-control actually takes place through the

prevention of the activation of an eating goal, which leads to actual control of real

consumption behavior in a subsequent taste test.

The model of similarity in consecutive response conflict and manuscript III.

At first sight, the findings in the second manuscript seem to conflict with the

ego-depletion literature. This literature states that exerting self-control taxes a limited

resource that is akin to energy or strength, and thus reduces people’s capacity to exert

self-control in the next phase (Muraven and Baumeister 2000). According to this

theory, the initial self-control exertion through resistance of the actionable food

temptation should lead to self-control failure in a subsequent task that requires self-

control (i.e., overconsumption in a taste test). In manuscript III, we explored this

apparent inconsistency with the ego-depletion literature. We found that the initial food

intake restriction task was depleting and thus decreased self-control performance in a

different domain, in this case reduced persistence on a subsequent anagram task, in

line with predictions from the ego-depletion literature. However, we again found that

the resistance to actionable food temptations resulted in self-control enhancement in a

9

subsequent taste test (as in manuscript II). These results and the contradiction with

ego-depletion can be explained from the cognitive control theory (Botvinick et al.

2001). This theory states that performance on tasks involving conflict improves

through temporal adaptation of one’s behavior to highly demanding situations. This

adaptation temporarily results in a more focused, conservative approach and thus an

increase in task performance, which spills over to a subsequent task with a similar

response conflict. At the same time, this temporary sustained activation of the rules

necessary to perform the task deteriorates task performance when the subsequent task

involves a different response conflict. These results suggest that self-control strength

theory (Muraven and Baumeister 2000) seems to apply only when the consecutive

self-control tasks involve different response conflicts. When two similar self-control

tasks follow each other, like in manuscript II, adjustment to the response conflict in

the first task seems to enhance self-control performance in a subsequent similar self-

control task. This implies that the exertion of self-control is not always detrimental to

subsequent self-control performance. In contrast, self-control exertion in one conflict

situation enhances self-control performance in a subsequent self-control requiring

situation if these consecutive self-control tasks involve a similar response conflict.

10

11

MANUSCRIPT I:

THE BACKDOOR TO OVERCONSUMPTION: THE

EFFECT OF ASSOCIATING ‘LOW-FAT’ FOOD WITH

HEALTH

ABSTRACT

We studied the influence of associating low-fat snack products with subtle

contextual health references (e.g., pictures of athletes) on the absolute consumption of

these products. The results of two experiments show that health references appear to

increase consumption of ambiguous products (i.e., low-fat potato chips). These results

suggest that associating ambiguous products with health messages may contribute to

rather than solve the obesity problem and have useful implications for public policy

and society.

12

OBESITY AND FOOD MARKETING PRACTICES

Obesity constitutes a growing health problem (Abelson and Kennedy 2004)

which increases in prevalence in most countries around the world (WHO 1998).

Although genetic determinants (Aitman 2003; Dietz 1991; Stunkard et al. 1991) play

a major role, the increasing prevalence of obesity suggests that societal changes and

worldwide nutrition trends (e.g., shifts towards less physically demanding work, more

varied diets with a higher proportion of fats, saturated fats and sugars, agricultural

productivity, federal food subsidies, and convenience-related trends) also contribute

to the problem (Cutler et al. 2003; Mitka 2003; Paeratakul et al. 2003). In addition,

market forces, like decreased prices, increased flavor variety (Raynor and Epstein

2001) and availability (Tardoff 2002), larger serving sizes (Nielsen and Popkin 2003;

Wansink 1996), and more convenient eating opportunities (e.g., ready to eat meals

and eating in restaurants), are often cited as driving the obesity epidemic (Critser

2003; Nestle 2002).

These environmental changes led, over the past decades, to an enormous

increase in the consumption of fattening snacks. Together with the reduction in

physical activity, increased caloric intake leads to energy imbalance and inevitably to

weight gain (Centers for Disease Control and Prevention (CDCP), 2004). Among

many other possible remedies, health organizations want to stimulate the market

penetration of low-fat products to reduce overall caloric intake. For example, the

WHO states that a remedy for obesity is “Creating supportive population-based

environments through public policies that promote the availability and accessibility of

a variety of low-fat, high-fiber foods, and that provide opportunities for physical

activity” (WHO 2004, italics added).

LOW-FAT PRODUCTS AND HEALTH REFERENCES

Low-fat snack foods (‘light’ products) are snack foods that are claimed to

contain less fat (i.e., a nutrient claim) but have an indistinguishable taste compared to

their ‘regular’ counterparts. Marketers present these low-fat snack products as

harmless for weight and health. These products therefore seem to offer the perfect

‘solution’ for dieters. Moreover, because of the focus on low-fat content, these

13

products are immediately associated to health, often reinforced by the label ‘low-fat’.

Consequently, it becomes ambiguous whether the low-fat snack product is either bad

for one’s health, in the same way as the regular products are, or good for it, as

suggested by the positioning advocated by marketers. Therefore, policy makers need a

more general understanding of the behavioral effects of the health associations

accompanying low-fat snack foods. Do they support dieting efforts by activating the

health goal? Or, more worrisome for society, do they lead to larger amounts

consumed or more frequent snacking, leading to overall status quo or even a net

increase in caloric intake? The study of the effects of positioning low-fat products as

healthy is timely because the World Health Organization encourages public policies

to promote the availability and accessibility of a variety of low-fat, high-fiber foods in

order to remedy the obesity problem (WHO 2004).

These health references (e.g., pictures of fibers, references in the brand name

(‘diet coke’), or pictures of athletes) that accompany low-fat products are different

from ‘health claims’. Health claims typically promise health enhancement or

reduction in the risk of disease (e.g., ‘It does your heart good’; Williams 2005). Prior

research examined the influence of health claims on consumer understanding,

knowledge, attitudes, perceptions, search, and product evaluation (Fullmer, Geiger,

and Parent 1991; Garretson and Burton 2000; Kozup, Creyer, and Burton 2003;

Mason and Scammon 2000; Mitra et al. 1999; Roe, Levy, and Derby 1999; Van

Assema et al. 1996). Overall, health claims make consumers believe the product to be

healthier when the nutrient information is unavailable, ambiguous, or consistent with

the claim.

Our aim is to explore the influence of associating low-fat snack products,

which are in line with legal prescriptions, with subtle contextual health references

(e.g., pictures of fibers, references in the brand name (‘diet coke’), or pictures of

athletes) on the consumed amount.

Prior research has shown that, among other factors, social factors (e.g.,

culture, the food industry, and the media) influence people’s attitudes towards certain

food products by praising or demonizing them (e.g., by associating the food with

health) (Oakes 2004; Rozin et al. 1999). Health associations might thus affect the

14

attitude towards the low-fat product they accompany. If health associations make low-

fat products seem healthier, exposure to health associations may increase absolute

consumption, thereby counteracting the caloric reduction from the reduced fat content

per serving. If, on the other hand, these health associations highlight that low-fat

products are not conducive to achieving long-term goals (slim body, good health,

etc.), exposure to health associations may decrease absolute consumption. So, from a

theoretical point of view, two alternative mechanisms can be identified that make

opposite predictions regarding the effect of health associations linked with low-fat

snack foods on the consumed amount. A self-control reinforcement mechanism would

predict that health associations would decrease the consumed amount whereas an

assimilation mechanism would predict that health associations would increase the

consumed amount in comparison with the control condition. We now elaborate on

both mechanisms.

TWO MECHANISMS OF BEHAVIORAL EFFECTS OF HEALTH

ASSOCIATIONS: SELF-CONTROL REINFORCEMENT VERSUS

ASSIMILATION

Health associations linked with low-fat snack foods might decrease the

consumed amount by activating the goal of living a healthy life and its associations in

memory (Metcalfe and Mischel 1999). Health goal activation should result in reduced

consumption of the low-fat snack product in comparison with the control condition.

Moreover, if health associations indeed activate a health goal, this should also result

in self-control reinforcement for regular snack products. Self-control reinforcement

would be reflected in empirical support for H1a and H2.

H1a: Associating low-fat snack products (i.e., ambiguous snack products) with

health results in a lower consumed amount compared to a situation without health

references. This hypothesis will be tested in studies 1 and 2.

H2: Associating regular snack products with health results in a lower

consumed amount compared to a situation without health references. This hypothesis

will be tested in study 2.

15

Alternatively, the health references accompanying low-fat snack foods may

influence the way the consumer perceives those products, as long as the presented

foods are a priori ambiguous with respect to health (Wheeler and Petty 2001). This

may result in assimilation effects (Stapel and Koomen 2001): The ambiguous object

(in this case the low-fat chips) may appear more compatible with health after

exposure to subtle health references than without these health references. Such

“assimilation” would make the low-fat snack food appear less threatening, allowing

consumption to increase in comparison with a situation without health references. In

other words, the health references might present these low-fat snack foods as

beneficial for health, resulting in decreased risk perception, higher consumption, and

possibly even higher overall caloric intake; also named “boomerang-effect” (Bolton,

Cohen, and Bloom 2006). Regular snack products are not ambiguous with respect to

health; it is generally agreed upon that these products are unhealthy and threatening

for health. Consequently, the health references should not have an influence on the

consumed amount of regular snack products. Assimilation would be reflected in the

support for H1b.

H1b: Associating low-fat snack products (i.e., ambiguous snack products) with

health results in a higher consumed amount compared to a situation without health

references. This hypothesis will be tested in studies 1 and 2.

STUDY 1

In the first study, we tested the effects of subtle health references on the

consumption of low-fat snack foods in middle-aged women. We pitted the two

possible mechanisms ‘assimilation’ and ‘self-control reinforcement’ against each

other. We introduced health references using a priming technique, resulting in two

conditions: a control condition without health references (neutral prime) and an

experimental condition with health cues (health prime). The aim of priming is to

activate a concept in long-term memory (usually below the awareness threshold) by

exposing participants to words related to that concept (Bargh and Chartrand 1999).

With this subtle priming technique, we simulated the presence versus absence of

health references in the environment, for instance in the TV commercial, or on the

package. Subsequently, we measured the amount of low-fat chips participants ate.

16

Method

Participants

In total, 37 female (aged between 27 and 57, mean age = 43.38, SD = 7.84)

members of a local research agency consumer panel participated in the study in

exchange for €15 worth of household products. Most of them were housewives.

Participants had a mean height of 1.63 meters (SD = 0.06) and a mean weight of 68.7

kg (SD = 11.4), for a mean BMI of 25.9 (SD = 4.5). Ten participants (27 %) were

overweight and seven (19 %) participants were obese.

Procedure

Participants entered the lab in groups of five to ten and were seated in

individual cubicles. They were randomly assigned to one of two experimental

conditions. The experimental conditions were randomized within each session and

over time of day.

Health vs. neutral prime manipulation. Participants first received a “language

test” that primed them with health words or with neutral words. The language test was

a scrambled sentences task (Bargh and Chartrand 2000). Each sentence consisted of

five words and participants were instructed to construct a grammatically correct four-

word sentence. In the health prime condition, 15 of the 30 sentences in the test

contained a word that was related to health. These 15 words (i.e., ‘healthy’, ‘apple’,

‘biking’, ‘jogging’, ‘fit’, ‘fruit’, ‘vegetables’, ‘laughing’, ‘lively’, ‘forest air’, ‘nature’,

‘kiwi’, ‘sleeping’, ‘sports’, and ‘vitamins’) were obtained from a pretest of 100

candidate words. The words were chosen in a way that ensured that the health-related

words would be used in the sentence composition. In the neutral prime condition the

health-related words were replaced by health-neutral words.

Taste test. Subsequently, participants received two bowls, each containing 50

grams of the same brand of light chips, and an evaluation form. They were told that

they were participating in a blind taste test between two different brands of light

17

chips. They had to rate each brand on several dimensions. They were allowed to eat as

many of the chips as needed to fill out the taste test evaluation form. All participants

had ten minutes to finish the taste test, which was sufficient for everyone. This

implies that participants could eat 10 chips per minute (which is a lot) if they would

eat all the chips.

Measures

Consumption. After the taste test, the remaining chips were weighted,

unbeknownst to the participants. Consumption, in grams, was summed over the two

bowls.

Reported eating behavior. At the end of the experiment, participants

completed the “Dutch Questionnaire of Eating Behavior” (van Strien, Frijters,

Bergers, and Defares 1986), in order to correct the results for the degree of dietary

restraint.

Hunger level. At the end of the questionnaire, participants had to indicate how

much time had elapsed since their last meal before entering the lab, as a proxy of their

hunger level.

Results

Effects of manipulations on the quantity consumed

We conducted an ANCOVA with Prime (Neutral or Health) as a between

subjects independent variable, and consumed grams of the low-fat chips as the

dependent variable. To control for the degree of dietary restraint, we included the

restraint score as a covariate in the analysis. This ANCOVA revealed a main effect of

Prime on the consumed grams low-fat chips, F(1, 34) = 4.28, p < 0.05. Consistent

with the assimilation mechanism and thus H1b, participants primed with health

consumed more (M = 18.07 gram, SE = 0.27) than participants in the neutral prime

condition (M = 10.96 gram, SE = 0.18).

18

Discussion

The results of the first study suggest that health associations linked with low-

fat snack foods increase the consumed amount. This implies that health references do

not seem to reinforce consumers’ self-control by activating the health goal and its

associations in memory. To the contrary, health references accompanying low-fat

snack foods apparently make the low-fat snack product appear more compatible with

the activated concept (in this case health) than without the health references, which

results in the higher consumed amount compared to a situation without health

references.

Our primary concern was to gain more insight in the effect of health

references on consumption amount of low-fat snack products. Therefore we

conducted a replication study, seeking generalization to men, to other features of

snack products that make them ambiguous with respect to health consequences

beyond the ‘low-fat’ label, and to another implementation of the health references

manipulation. In addition, in this second study, we also included a regular snack

product in the taste test to gain further insight in the processes (i.e., a self-control

reinforcing process vs. an assimilation process). Regular snack products are not

ambiguous with respect to health. Consequently, the health references should not have

an influence on the consumed amount of regular snack products, serving as an

additional support of the assimilation mechanism.

STUDY 2

In the second study, we tested the effects of health references on the

consumption of regular snack foods and snack foods that are ambiguous with respect

to health. The presence of health references was manipulated using a text framing the

snack product as being healthier than everyone beliefs. This resulted in two

conditions: a control condition with a general description of the snack product (neutral

frame) and an experimental condition with a healthier description (healthy frame). We

then measured the amount of ambiguous and regular chips participants ate in a

subsequent taste test.

19

Method

Participants

Fifty-six undergraduate students (36 women) participated in exchange for €7.

They had a mean height of 1.74 meters (SD = 0.09) and a mean weight of 67.04 kg

(SD = 12.2), for a mean BMI of 22.22 (SD = 3.7). Six participants (10.7%) were

overweight and two (3.6%) participants were obese.

Procedure

Participants entered the lab in groups of eight and were seated in individual

cubicles. They were randomly assigned to one of two experimental conditions. The

experimental conditions were randomized within each session and over time of day.

Framing manipulation. First, participants were asked to read a text containing

information about chips in general. In the neutral frame condition, the text described

some general facts about chips everyone is familiar with. In the healthy frame

condition, participants received a text that framed chips as being healthier (i.e.,

containing lots of vitamins, minerals, and fibers and only small amounts of fat) than

everyone beliefs.

Taste test. Subsequently, participants received two bowls, each containing 50

grams of chips, and an evaluation form. They were told that one bowl contained

regular chips, made of potatoes, and the other bowl contained a new kind of chips,

made of manioc, which contains less starch. No mention about the healthiness of the

new kind of chips was given, which made the chips ambiguous with respect to health.

Participants were asked to evaluate both kinds of chips on several dimensions. They

were allowed to eat as many of the chips as needed to complete the taste test

evaluation form. All participants had ten minutes to finish the taste test, which was

sufficient for everyone.

20

Measures

Consumption. After the taste test, the bowls were removed, and the

experimenter weighed, for each bowl, how many grams of chips had been consumed.

The reported eating behavior (i.e., dietary restraint) and the hunger level of the

participants were measured as in study 1.

Results and discussion

Effects of manipulations on the consumed amount

We conducted a repeated measures ANCOVA with Type of Chips

(Ambiguous or Regular) as a within subjects independent variable, Framing (Neutral

or Healthy) as a between subjects independent variable, and consumed grams as the

dependent variable. To control for the degree of dietary restraint, we included the

restraint score as a covariate in the analysis. The ANCOVA revealed a marginally

significant interaction between Type of Chips and Framing, F(1, 53) = 3.07, p < .09.

The Framing manipulation had a significant effect on the consumed amount of

the ambiguous chips, F(1, 53) = 3.91, p = .05 (see figure 1.1). Participants in the

Healthy Frame condition (M = 7.95 gram, SE = 1.02) consumed more of the

ambiguous chips than participants in the Neutral Frame condition (M = 5.15 gram, SE

= 0.98), replicating the findings of study 1 and supporting H1b. Again, the findings are

incompatible with a self-control reinforcing mechanism (H1b). Moreover, H2 is

disconfirmed, again supporting the assimilation mechanism.

For the regular chips, the consumed amount of the regular chips did not differ

between the Neutral (M = 6.12 gram, SE = 0.95) and the Healthy (M = 7.11 gram, SE

= 0.91) Frame condition (F<1), which is again inconsistent with a self-control

reinforcing mechanism.

21

FIGURE 1.1

Consumption at the taste test (Regular and Ambiguous Chips) as a function of

Frame (Neutral or Health); study 2.

0

1

2

3

4

5

6

7

8

9

10

Ambiguous Regular

Co

nsu

med

gra

ms c

hip

s

Neutral Frame

Health Frame

The Healthy Framing condition led participants to increase consumption of the

ambiguous chips and not of the regular chips in comparison with the Neutral Framing

condition. These results imply that framing a product category as healthy affects only

the consumption of products in that category which are ambiguous with respect to

health. Labeling these ambiguous snack products as being low-fat is not necessary.

Leaving the healthiness of the snack product ambiguous and open to interpretation

seems to be sufficient for health references to increase consumption. For

unambiguously unhealthy products (i.e., regular chips) the health frame has no effect;

consumption remains at the same level as the neutral frame condition.

GENERAL DISCUSSION

Overview of the findings

The aim of our research was to explore whether subtle health references

discourage or encourage consumption of snack foods that are ambiguous with respect

to health (e.g., low-fat chips). We distinguished two potential effects of subtle health

references in a consumer’s food decision environment. First, such references may

reinforce consumers’ self-control by the activation of people’s long-term goals related

22

to health. Second, health references may affect the interpretation of the ambiguous

temptation. This mechanism would make consumers more vulnerable to ambiguous

temptations, because it would appear less threatening than it actually is. In our studies,

we found no evidence for the self-control reinforcing process at all. Rather, we found

that health references increased consumption, in comparison with a situation without

health references, of food that is ambiguous with respect to health consequences. We

did not find any effect of the health references for unambiguously unhealthy food.

Implications for Consumer Welfare and Public Policy

For marketers, our results might sound like good news in the short run given

the recent boom in the demand and supply of low-fat and other ‘light’ products

(American Dietetic Association 1998). By associating these products with health,

marketers can increase sales and profit. For society in the long run, however, our data

imply that the promotion of low-fat snack foods, positioned as healthy, may be a

counterproductive strategy to halt the obesity epidemic. Low-fat snack products are

better for health than their regular counterparts. However, their associations with

health references (e.g., pictures of fibers, references in the brand name (‘diet coke’),

or pictures of athletes) might counteract the intended caloric reduction by affecting

the healthiness perception of the ambiguous snack product. According to the

assimilation mechanism (Stapel and Koomen 2001), these health references might

make an ambiguous snack product seem healthier than it actually is and consequently

lead to an increased consumption and possibly even an increased absolute caloric

intake.

In the United States, the Nutritional Labeling and Education Act of 1990

(NLEA) already developed instructions concerning the availability of nutrition

information on food packages and health claims. These instructions, however, do not

deal with subtle health references accompanying existing low-fat snack products, such

as pictures of athletes or labels such as ‘light’. In Europe, instructions concerning

nutrient and health claims are even less developed. Our findings suggest that these

existing instructions should be adjusted by two possible policies.

23

One option may be to decrease the fat content of snack products without

emphasizing this too strongly on the package and in ads. In this case, there would be

no or fewer health references that may increase consumption of the product that is less

unhealthy. Along this line, policy makers may want to consider setting maximum

caloric densities for certain highly popular and fattening product categories, such as

potato chips, chocolate, etc.

An alternative option would be to instruct food manufacturers to provide more

explicit information to consumers in order to avoid ambiguous interpretations of the

low-fat snack products with respect to health. Consider the example of potato chips.

Food manufacturers mention the reduced percentage of fat in their products (e.g., 33%

for the product we used in study 1) which is much more impressive than the reduced

percentage of calories (which was only 11% for the product we used in study 1, due

to starch, sugar, etc.). So, along with this information about the fat content, the

information concerning the absolute caloric level, cholesterol and other unhealthy

ingredients should be emphasized clearly and saliently on the package, instead of as

small print on the back of the package. Mentioning ‘11% fewer calories’ probably

would have less influence on the consumed amount of the low-fat product compared

to mentioning ‘33% less fat’, because ‘11% fewer calories’ is less ambiguous with

respect to health.

Raynor et al. (2004), for example, suggested that interventions to reduce fat

intake should target increasing liking for low-fat foods, along with increasing the

proportion of low-fat food in the household. Our results imply that these interventions

should be carefully considered in order to prevent consumers to perceive these low-fat

snacks products as being healthier than they really are. Together with our results, this

suggests that people might end up consuming as many calories or even more calories

than when they would consume traditional high fat food.

Further Research and Limitations

We acknowledge that a limitation of this research concerns the short period of

time of the consumption opportunity, and we should be careful in drawing

conclusions in the long-run. Moreover, eating behavior in a laboratory is not the same

24

as real eating behavior. However, research concerning the effects of environmental

stimuli on food intake mostly uses these kinds of methods and analyses (Roefs and

Jansen 2004; Rotenberg et al. 2005). In addition, we argue that the consumption

pattern in the control condition (i.e., the neutral prime/frame condition) can be

assumed to reflect normal eating, and that the relevant information is in the difference

between the control and the experimental condition. Our results should serve as initial

evidence that deserves further exploration.

It has been shown that consumers do ration the purchase quantities of ‘vice’

products (i.e., products that satisfy a short-term desire but hurt the attainability of

long-term goals (e.g., regular potato chips)) in order to solve their self-control

problem (Wertenbroch 1998). They do so because they believe that limiting the stock

of vice products reduces the temptation to overconsume vices. To reach that objective,

consumers are even prepared to forgo quantity price discounts. For (relative) ‘virtue’

products such as low-fat potato chips (i.e., products that provide more utility in the

long-run than (relative) vice products), the data and our interpretation in terms of

assimilation suggest that consumers probably do experience less to no self-control

threat. Hence, they could tend to stockpile these virtue products at home. However,

stockpiling makes people consume convenience products at a faster rate (Chandon

and Wansink 2002). This implies that low-fat versions of unhealthy snacks may be

more readily stockpiled at home and that health references (e.g., in advertisements, or

on packages) may encourage overconsumption of these low-fat snacks. It would be

interesting to explore the stockpiling and subsequent consumption behavior of virtue

products.

More research is also required to investigate boundary conditions (e.g., how

(un)ambiguous can the product be?), possible ways to reduce the overconsumption

effect due to subtle health references, and whether weaker health cues still lead to

increased consumption. The effects in the long run should also be explored. The final

goal should be a detailed understanding of the various ways in which marketing

promotes, obstructs, and generally interacts with consumer’s health and self-control

and how public policy agencies can combat these consumption increasing strategies.

25

MANUSCRIPT II:

TEMPT ME JUST A LITTLE BIT MORE. THE EFFECT

OF FOOD TEMPTATION ACTIONABILITY ON GOAL

ACTIVATION AND SUBSEQUENT CONSUMPTION

ABSTRACT

In daily life, people are often exposed to food temptations like ads for

chocolate or friends offering cookies. This article examines whether food temptations,

differing in actionability (presence vs. absence of an opportunity to consume), lead

consumers to eat more, or rather help them in exerting self-control. The results of five

experiments suggest that pre-exposure to actionable food temptations enhances self-

control on a subsequent consumption occasion, by preventing the activation of the

eating goal. Pre-exposure to non-actionable food temptations lead to self-control loss

on a subsequent consumption occasion.

26

In everyday life, consumers often are exposed to food temptations; in ads, in

stores, in bakeries, on coffee tables during social visits, and even in one’s own

refrigerator… Food temptations might activate a desire for the cued food and increase

its consumption (Fedoroff, Polivy, and Herman 2003; Lambert and Neal 1992).

However, salient food temptations might also remind consumers of their food restraint

objectives, and thus facilitate self-control (Fishbach, Friedman, and Kruglanski 2003).

So, food temptations might sometimes help but also sometimes hurt the consumer’s

resistance to subsequent tempting food offers. In this article we attempt to find out

when food temptations hurt or help food intake regulation.

FOOD TEMPTATIONS MAY HURT RESISTANCE TO

SUBSEQUENT FOOD TEMPTATIONS

Prior research and observations from everyday life support the common

intuition that food temptations constitute a direct permanent threat to the

accomplishment of consumers’ long term food intake regulation goals. Indeed, larger

package sizes increase consumption (Wansink 1996) and stockpiling accelerates the

consumption rate of convenience goods due to a higher salience of the food products

(Chandon and Wansink 2002). Other research has shown that external cues like visual

(e.g., seeing half a cake on a counter) or aromatic prominence (e.g., the scent of

cookies in a room) of food can make it salient (Painter, Wansink, and Hieggelke

2002; Schachter 1971; Wansink 1994). The increase in food salience following

appetizing olfactory food cues has been shown to activate a craving for food and

stimulate eating behavior (Fedoroff et al. 2003; Lambert and Neal 1992). Shiv and

Fedorikhin (2002) found that increasing the salience of the food options in a choice

task, by placing the options in front of consumers rather than showing pictures of the

food, causes an affect-laden food option (e.g., pizza) to be preferred over a less affect-

laden food option (e.g., tomato soup). The salient food options are likely to activate

appetitive goals (Shiv and Fedorikhin 2002). These findings suggest that exposure to

appetizing external food cues arouses the desire to eat or an eating goal. The

activation of the eating goal appears to increase consumption on a subsequent

consumption occasion in comparison with a situation without external food cues.

According to the affective-cognitive framework (Shiv and Fedorikhin 2002; Shiv,

Fedorikhin, and Nowlis 2005), these direct effects are represented by the lower-order

27

pathways in figure 2.1. Namely, exposure to affect-laden stimuli (i.e. food) gives rise

to spontaneous lower-order cognitions and affect that lead to a desire for and a

tendency to grab the food.

Food temptations may also have an indirect facilitating effect on consumption

quantity. Resisting food temptations requires self-control. When the desire for eating

is greater than the consumer’s willpower to control food intake in order to achieve

long-term goals, self-control is lost (Hoch and Loewenstein 1991; Loewenstein 1996;

Metcalfe and Mischel 1999). Maintaining self-control seems to require attention to

inhibitory goals, represented by the higher-order cognitions in figure 2.1 (for the time

being, ignore the ‘threat’ detector, which will be discussed in the hypotheses section).

These higher-order processes take place through deep deliberation of all information

related to the food (e.g., the adverse consequences of consuming food) and might help

to overcome the desire to eat by activating inhibitory goals. When attention is diverted

from inhibitory goals (Baumeister et al. 1998) and narrowed to the most salient cue

(Ward and Mann 2000), self-control is lost. Because trying to avoid eating food keeps

the mental representation of a food temptation active, the most salient cue is–

ironically–often the food itself (Wegner 1994). The increased focus on food cues that

results from self-control attempts therefore might result in increased consumption

when attention is distracted from the inhibitory goals that underlie these self-control

attempts. According to the affective-cognitive framework (Shiv and Fedorikhin 2002;

Shiv et al. 2005), narrowing thoughts to the most salient stimulus (i.e., the food) can

indeed trigger higher-order affect which reinforces the tendencies arising from the

lower-order affect (i.e., eat the food). This framework is based on the proposition by

LeDoux (1996) that affective reactions can also arise in a relatively controlled manner

following cognition rather than preceding cognition (i.e., a view held by Zajonc

(1980)). In support of this indirect effect of self-control attempts on the consumption

of tempting food, Shiv and Fedorikhin (1999) found that limitations of processing

resources increased preference for affect-laden food (i.e., chocolate cake) over less

affect-laden food (i.e., fruit salad) for people with weak self-control capacity.

Together, the findings described above all support the common intuition that

food temptations may be detrimental to food intake regulation in many circumstances.

However, some recent findings in literature (Fishbach et al. 2003; Gilbert et al. 2004)

28

suggest that food temptations may actually enhance self-control, possibly resulting in

decreased consumption. This would be the case if the path from the higher-order

cognitions to the self-control requiring situation does not trigger the higher-order

affect (see figure 2.1).

FIGURE 2.1

Affective-cognitive framework adapted for threat detector

FOOD TEMPTATIONS MAY HELP RESISTANCE AGAINST

SUBSEQUENT FOOD TEMPTATIONS

Indeed, food temptations have been shown to activate inhibitory goals

(Fishbach et al. 2003), as represented by the higher-order cognitions in figure 2.1,

which may help consumers to control their food intake, at least if higher-order affect

is not triggered. Recently Fishbach and Shah (2006) also found that, in addition to the

activation of the overriding goal, the automatic response to food stimuli is a tendency

to approach these stimuli. However, at the same time, especially for dieters, there is

an automatic tendency to avoid these food stimuli. This suggests that the self-control

conflict caused by exposure to food cues emerges by the simultaneous approach and

Food Cue

Higher-Order Affect: Eating

Higher-Order Cognition: Restriction

Consumption

Lower-Order Cognition Lower-Order Affect

Threat YES

NO +

-

29

avoidance tendencies that they induce. Self-control is successful when the original

tendency to approach these stimuli is overridden by the tendency to avoid the stimuli.

The prediction that food temptations might help resistance against subsequent food

offers may also be derived from Gilbert et al.’s (2004) finding that active attempts to

solve a problem arise only when the problem becomes serious enough. People’s

problem solving strategies seem to be triggered only by critical levels of hedonic

states because they expect intense states (e.g., pain from a bruised leg) to last longer

than mild states (e.g., pain from a numb leg). Intense hedonic states are overestimated

(Gilbert et al. 1998) and trigger self-control strategies, whereas mild states are

underestimated and therefore linger unsolved (Snell, Gibbs, and Varey 1995). In the

case of food temptations, a similar non-linear relationship might apply. A large

number of candies may trigger concerns about health and diet objectives whereas

small numbers might not. This implies that people might paradoxically consume more

candies when there are only a few candies in the kitchen cabinet than when a lot of

candies are present (Gilbert et al. 2004) although consumers seem to believe the

opposite (Wertenbroch 1998). The application of Gilbert et al.’s (2004) theory to the

food consumption domain implies that consumers might be wrong when they buy

smaller amounts of vice foods as a strategy to keep their consumption under control.

According to the critical level perspective, exposure to food temptations that exceed

the critical level beyond which self-control strategies are triggered, might help to

control food intake on a subsequent consumption occasion. Applied to the affective-

cognitive framework (Shiv and Fedorikhin 2002; Shiv et al. 2005), this suggests that a

certain mechanism is needed that determines whether higher-order affect is activated.

We will get to the bottom of this mechanism in the next section.

HYPOTHESES

In all, then, food temptations may sometimes increase food intake on a

subsequent consumption situation through the activation of eating goals and

sometimes decrease food intake on a subsequent consumption occasion through the

activation of inhibition goals. However, little is known about the specific

circumstances that determine whether an increase or decrease is obtained. In the

current article, we focus on the degree to which the food is threatening as an

important situational moderator. We will compare food temptations that do not offer

30

the opportunity to consume the food temptation and food temptations that do offer the

opportunity to consume the food temptation with respect to their effects on

subsequent consumption. We compare those effects with a control condition without

prior temptation. The main difference between the two types of temptation lies in the

actionability of the temptation. The food temptation that is not actionable (e.g.,

pictures of food) is not threatening because the consumer cannot consume the

temptation directly. In contrast, the food temptation that is actionable (e.g., a basket

full of delicious cookies) is threatening because it can be consumed immediately. We

assume that actionable food temptations exceed the critical level beyond which self-

control strategies are triggered (Gilbert et al. 2004). On the other hand, we assume

that non-actionable food temptations are not threatening and consequently do not

exceed the critical level. As a result, we expect that exposure to non-actionable food

temptations will increase the desire to eat. According to the affective-cognitive

framework (Shiv and Fedorikhin 2002; Shiv et al. 2005), the more vivid and affective

the food cue, the more likely the focus of higher-order processes is on the hedonic

qualities of the food cue, resulting in higher-order affect (i.e., desire to eat). However,

if we take the findings of Fishbach et al. (2003) and Gilbert et al. (2004) into account,

we suggest that an additional decision step (i.e., the threat detector) should be added

to the affective-cognitive framework (Shiv and Fedorikhin 2002; Shiv, Fedorikhin,

and Nowlis 2005). If a food cue exceeds the critical level beyond which self-control

strategies are triggered, the threat detector will be activated and will prevent the

triggering of higher-order affect. In this way, self-control loss will be prevented. Food

temptations that are threatening (i.e., actionable food temptations) should thus only

trigger higher-order cognitions under the form of food restriction goals (Fishbach et

al. 2003) and no higher-order affect (i.e. the activation of a desire to eat). Non-

threatening food cues (i.e., non-actionable food temptations), on the other hand,

should not activate the threat detector. Therefore, higher-order cognitions will result

in higher-order affect (i.e., a goal to eat). Moreover, the possible activation of higher-

order affect takes place after higher-order cognition (LeDoux 1996; Shiv and

Fedorikhin 2002; Shiv et al. 2005), implying that the activation of the eating goal is

delayed compared to the activation of the food restriction goal.

H1: Exposure to food temptations (non-actionable and actionable) triggers

higher-order cognitions under the form of food restriction goals, in

comparison with no prior exposure to food temptations (study 1A).

31

H2: After the activation of the higher-order cognitions (the food restriction

goal), exposure to non-actionable food temptations should trigger

higher-order affect (the eating goal) to a larger extent than exposure to

actionable food temptations (study 1B and study 2).

Cues that render food more salient typically increase its consumption

(Fedoroff et al. 2003; Lambert and Neal 1992; Painter et al. 2002; Wansink 1994,

2004). If exposure to actionable food temptations enhances self-control, the typical

effect of food cues on subsequent consumption should be suppressed. Non-actionable

food temptations do not trigger self-control strategies because they are not

threatening. As a result, the desire to eat activated by exposure to non-actionable food

temptations should result in increased food intake.

H3: Exposure to actionable food temptations is more likely to trigger self-

control processes, which will suppress the effect of food cues that have

been shown to increase consumption, in comparison with exposure to

neutral stimuli and exposure to non-actionable food temptations (study

3A&B).

H4: Exposure to non-actionable food temptations will increase consumers’

consumption in subsequent consumption situations, in comparison with

exposure to neutral stimuli and exposure to actionable food temptations

(study 3A&B).

In study 1, we tested the effects of types of food temptations (Control vs. Non-

Actionable Food Temptation vs. Delayed Actionable Food Temptation vs. Immediate

Actionable Food Temptation) on the immediate activation of a food restriction goal

(study 1A; H1) and the delayed activation of the eating goal (study 1B; H2). In the

second study, we performed a second and better test of the effect of temptation type

on the delayed activation of the eating goal by adding an additional threat. In the third

and last study, we tested the effects of food temptations on subsequent consumption

behavior. In order to test for self-control enhancing effects of actionable food

temptations (H3), we manipulated the convenience of the food offered in the

subsequent consumption situation in study 3A (food cue internal to the subsequent

consumption situation) and an olfactory cue (food cue external to the subsequent

32

consumption situation) in study 3B and evaluated whether actionable food

temptations inhibited the consumption increase that typically follows these cues.

STUDY 1

In study 1, we measured concept/goal activation resulting from temptation

manipulations differing in actionability. This goal activation was measured by means

of a lexical decision task, with faster recognitions of words signifying activation of

associated concepts. We expect all the food temptations, independent of their

actionability, to directly activate a food restriction goal (Fishbach et al. 2003; Shiv

and Fedorikhin 2002; Shiv et al. 2005), as we stated in H1. The food restriction goal

activation was measured in study 1A. Moreover, according to the affective-cognitive

framework (Shiv et al. 2005), after the activation of higher-order cognitions, higher-

order affect (i.e., the goal to eat) might also be triggered (Shiv and Fedorikhin 2002;

Shiv et al. 2005). We state that higher order processes result in the activation of

higher-order affect only if the critical level beyond which self-control strategies are

triggered is not exceeded. In addition, we assume that actionable food temptations, in

comparison with non-actionable food temptations, exceed this critical level because

they are threatening to the achievement of long-term goals (i.e., being slim or

healthy). To verify this assumption, we measured the activation of the eating goal

after a short delay in order to allow the prior activation of higher-order cognitions to

affect higher-order affect. We hypothesized that the eating goal will be activated to a

higher extent after exposure to non-actionable food temptations than after exposure to

actionable food temptations because the latter will trigger self-control strategies which

prevent the activation of this eating goal. In other words, an actionable temptation

may trigger processes enhancing self-control of food intake whereas a non-actionable

temptation does not. This second hypothesis was tested in study 1B.

33

STUDY 1A

Method

One hundred female undergraduate students (age between 18 and 26)

participated for partial fulfillment of a course requirement. The temptation conditions

were run in separate sessions for procedural efficiency in all studies. Each session was

run in groups of maximum eight participants.

Temptation manipulation. On entering the laboratory, participants were given

a knowledge task. In the Non-Actionable Food Temptation condition, participants

were told that the manufacturer of the ‘Quality Street’ candies, which exist in

twelve different flavors, was interested in consumer knowledge of the association

between flavors and wrapper colors. Participants were asked to associate twelve

pictures of the candies (of different colors and shapes) with the corresponding flavor

of each candy (e.g., ‘chocolate with strawberry cream’). In the Delayed Actionable

Food Temptation condition, participants were given the same task while a bowl filled

with lots of these ‘Quality Street’ candies was present next to them. They were told

that the candies were placed there because the pictures were not always very clear.

They were not allowed to eat any candy during the knowledge task. This was done in

order to prevent people from consuming the food used in the knowledge task.

However, this instruction in itself may affect the activation of the food restriction

and/or the eating goal. To rule out this concern, an Immediate Actionable Food

Temptation condition was added, which was identical to the Delayed Actionable Food

Temptation condition except for the instruction that participants were not allowed to

eat the candies during the task. In fact, in the Immediate Actionable Food Temptation

condition, nothing was mentioned about the candies. If actionable food temptations

trigger self-control processes, the findings should be comparable in both actionable

conditions. Participants in the Control condition (i.e., no food temptation) were asked

to match ten colors with ten concepts (e.g., ‘white’ with ‘snow’ and ‘green’ with

‘grass’).

Lexical Decision Task. Right after the temptation manipulation and before

they had the opportunity to consume the candy in the Delayed Actionable Food

34

Temptation condition, participants received the second task. This task consisted of a

lexical decision task, with faster recognitions of words signifying that the

corresponding concept is activated. Following a two second warning screen that

included a fixation cross, a stimulus word appeared on the computer screen.

Participants had to respond as quickly and accurately as possible by pressing one of

two keys to indicate whether the stimulus was a word or a pseudo-word. Response

times (in milliseconds) and accuracy were recorded. To familiarize them with the

task, participants started with a practice round of 10 trials (five neutral words and five

pseudo-words). Fifty-two actual trials followed, including 16 target words related to

food restriction, 10 neutral words, and 26 pseudo-words. The 16 goal-related words

were obtained from a pretest (n = 38) in which we asked participants which thoughts

came to mind when they thought about food restriction (e.g., ‘diet’ and ‘slim’). The

words were shown in fixed order to exclude any cross-over effects, with ‘diet’ as the

first displayed goal-related word because this word interested us most.

Results and Discussion

The screening procedure led us to exclude four women who did not like the

candy. Additionally, four outliers were removed (i.e., 4.2 %, defined as deviating at

least three standard deviations from the mean in their respective conditions), leaving

92 participants in the analyses.

Response time. We conducted an ANCOVA with Temptation as a between

subjects independent variable, and response time on the first food restriction word

‘diet’ as the dependent variable. To control for the substantial inter-individual

variability in latencies, we included the average response time on the neutral words as

a covariate in the analysis (Fazio, 1990). The ANCOVA revealed a significant main

effect of Temptation, F(3, 87) = 5.48, p < .003. In comparison with the Control

condition (M = 609.58, SD = 119.48), ‘diet’ was recognized faster, in the Non-

Actionable Food Temptation condition (M = 520.40, SD = 80.21, F(1, 87) = 13.80, p

< .0004), the Delayed Actionable Food Temptation condition (M = 552.22, SD =

84.41, F(1, 87) = 5.70, p < .02), and the Immediate Actionable Food Temptation

condition (M = 526.40, SD = 58.34, F(1, 87) = 11.31, p < .002). These results

replicate the findings of Fishbach et al. (2003) and support hypothesis 1. There were

no significant differences in activation among the three conditions with a food

35

temptation (all F’s < 2). The results of study 1A show that non-actionable as well as

actionable food temptations activate the goal to restrict food intake, replicating the

findings of Fishbach et al. (2003). Moreover, the results show that the presence of the

instruction not to eat the candies does not matter; the delayed actionable food

temptation does not differ from the immediate actionable food temptation.

STUDY 1B

Method

One hundred and eleven female undergraduate students (age between 18 and

24) participated for partial fulfillment of a course requirement.

Temptation manipulation. The temptation manipulations were identical to

those used in study 1A.

Lexical Decision Task. Right after the temptation manipulation and before

they had the opportunity to consume the candy in the Delayed Actionable Food

Temptation condition, participants received a lexical decision task with a procedure

similar to the one in study 1A. However, there were 100 actual trials, including 24

neutral words at the start, 16 target words related to eating (e.g., ‘eating’ and

‘mouthwatering’; obtained from a pretest (n = 38) in which we asked participants

which thoughts came to mind when they thought about eating), 10 neutral words

mixed between the eating words, and 50 pseudo-words. Before the eating-related

words, the first 24 neutral words and 26 pseudo-words were shown; resulting in a

delay of five min. on average. This delay was added in order to take the activation of

higher-order cognitions preceding the activation of higher-order affect into account

(consistent with the cognitive-affective framework, Shiv et al. 2005, see figure 2.1).

The words were shown in fixed order to exclude any cross-over effects, with ‘eating’

as the first displayed goal-related word because this word interested us most.

36

Results and Discussion

The screening procedure led us to exclude six women who did not like the

candy. Additionally, two outliers were removed (i.e., 1.9 %, defined as deviating at

least three standard deviations from the mean in their respective conditions), leaving

103 participants in the analyses.

Response time. We conducted an ANCOVA with Temptation as a between

subjects independent variable, response time on the first eating-related word ‘eating’

as the dependent variable and the average response time on the neutral words as a

covariate. The ANCOVA revealed a significant main effect of Temptation, F(3, 98) =

2.70, p < .05. In comparison with the Control condition (M = 510.20, SD = 123.11),

‘eating’ was recognized faster, in the Non-Actionable Food Temptation condition (M

= 455.24, SD = 64.98, F(1, 98) = 6.04, p < .02), the Delayed Actionable Food

Temptation condition (M = 460.07, SD = 59.43, F(1, 98) = 5.00, p < .03), and the

Immediate Actionable Food Temptation condition (M = 456.09, SD = 81.46, F(1, 98)

= 5.86, p < .02). There were no significant differences in activation among the three

conditions with a food temptation (all F’s < 1). This implies that the eating goal is

activated in all food temptation conditions after a 5 min. delay, which does not

support hypothesis 2. The results of study 1B show that non-actionable as well as

actionable food temptations activate the eating goal. The activation of this higher-

order affective goal is thus not prevented in the actionable food temptation conditions.

Again, the results show that the presence of the instruction not to eat the candies does

not matter; the delayed actionable food temptation does not differ from the immediate

actionable food temptation. There are two possible explanations for the fact that we

do not find evidence for the second hypothesis. On the one hand, it could be that our

proposed model is not correct and that the eating goal is always activated by food

cues, independent of the threat level of the temptation. On the other hand, it might be

the case that the self-control conflict created by the actionable food temptations is not

threatening enough to exceed the critical level. In other words, the presence of a

second actionable and thus threatening food cue might be necessary in order to exceed

the critical level that is hypothesized to activate the threat detector (figure 2.1) and

hence inhibit the activation of the higher-order affect.

37

The latter explanation has several implications for the predicted pattern of

results. In the control condition, the eating goal should be activated too in comparison

with study 1B because of the presence of an actionable food temptation. In addition,

after exposure to the non-actionable food temptation, the effect of the second

actionable food cue should also be identical to the effects of the actionable food

temptation conditions in study 1B because the initial non-actionable food temptation

is not threatening at all. However, in both actionable conditions, we expect that the

second actionable food temptation that is present during the lexical decision task

should push consumers beyond the critical level (i.e. activate the threat detector),

which should prevent the activation of the eating goal. In order to test these possible

explanations, we conducted a second study, which was identical to study 1B except

that an actionable food temptation was added during the lexical decision task.

STUDY 2

The second study was set up to test whether our model is incorrect or the

critical level was not exceeded in study 1B. Therefore, we measured the eating goal

activation as in study 1B in the presence of an actionable food cue (i.e., two bowls of

M&Ms destined for a subsequent taste test). Overall, we expected an activation of the

eating goal in the control condition and the non-actionable food temptation condition

compared to the two actionable food temptation conditions, because there is a double

threat in the actionable food temptation conditions resulting from surpassing the

critical level. This surpassing should lead to self-control strategies that prevent the

activation of the eating goal.

Method

Seventy-nine female undergraduate students (age between 18 and 25)

participated for partial fulfillment of a course requirement.

Temptation manipulation. The temptation manipulations were identical to

those used in study 1.

Lexical Decision Task. Right after the temptation manipulation and before

they had the opportunity to consume the candy, participants received a lexical

38

decision task, identical to the one in study 1B. In addition, two bowls of the same

volume, one with regular M&Ms (400 grams), and the other with the ‘new’ crispy

M&Ms (300 grams) were placed in front of them while they started the lexical

decision task. These M&Ms were accompanied by a paper message which stated that

they were meant for a subsequent taste test.

Results and Discussion

The screening procedure led us to exclude three women who did not like the

candy. Moreover, three other women were excluded because they consumed some of

the candies before starting the lexical decision task. Additionally, three outliers were

removed (i.e., 4.1 %, defined as deviating at least three standard deviations from the

mean in their respective conditions), leaving 70 participants in the analyses.

Response time. An ANCOVA testing the effects of Temptation on the

response time for the word ‘eating’ (in ms) with the average response time on the

neutral words as a covariate, revealed a significant main effect of Temptation, F(3,

65) = 4.08, p < .02. As we expected, in comparison with the Control condition (M =

448.20, SD = 46.72), the activation of the eating goal was prevented in the Delayed

Actionable Food Temptation condition (M = 505.44, SD = 72.34, F(1, 65) = 3.78, p <

.06) and the Immediate Actionable Food Temptation condition (M = 525.82, SD =

144.80, F(1, 65) = 7.40, p < .009). In comparison with the Non-Actionable Food

Temptation condition (M = 442.98, SD = 52.39, the eating goal was activated to a

lesser extent in the Delayed Actionable Food Temptation condition (M = 505.44, SD

= 72.34, F(1, 65) = 4.52, p < .04) and the Immediate Actionable Food Temptation

condition (M = 525.82, SD = 144.80, F(1, 65) = 8.11, p < .006). A planned contrast

between the Control condition and the Actionable Food Temptation condition on the

one hand (M = 445.73, SD = 49.31) and the two Actionable Food Temptation

conditions on the other hand (i.e., Delayed and Immediate) (M = 516.10, SD =

115.89) revealed a highly significant difference, (F(1, 67) = 12.05, p < .002).

These findings suggest that exposure to actionable food temptations prevents

the activation of the eating goal when a subsequent food opportunity is offered. The

presence of the subsequent food threat is necessary in order to find this prevention of

39

the activation of an eating goal. The second threat (M&Ms) seems to make the threat

detector active which triggers the self-control path in the Delayed and Immediate

Actionable Food Temptations conditions. The next study addresses the question

whether the goal activation reported in studies 1 and 2 transfers to a real consumption

situation.

STUDY 3

In study 3, we tested whether the self-control processes that are triggered when

the critical level of temptation is exceeded actually enhance self-control in a real

consumption situation. As we stated in the third and fourth hypotheses, the initial

exposure to actionable food temptations will push consumers beyond the critical level

when a subsequent actionable food temptation is offered (study 2). The expected

result is a decrease in consumption. Non-actionable food temptations are not

threatening and therefore do not activate the threat detector (figure 2.1). An initial

exposure to non-actionable food temptations does not add to reaching the critical

level. However, as shown in studies 1B and 2, exposure to non-actionable food

temptations activates the eating goal. Therefore, we expect self-control loss, as

reflected by a consumption increase, in the non-actionable temptation condition

compared with the control condition. If, as suggested by the findings of study 2, the

subsequent actionable food offer is combined with an initial exposure to actionable

food temptations, the activation of an eating goal will be prevented. In this way, the

typical consumption increase following consumption stimulating cues will be

suppressed in the Actionable Food Temptation condition.

In study 3A, we rely on the well-documented effect that the convenience of

the food offered increases consumption (Federoff et al. 2003; Wansink 2004). In

study 3B we rely on the well-documented effect that appetizing food cues such as

scent increase consumption. If an actionable food temptation prevents the activation

of the eating goal, it should suppress the typical convenience and scent effects at the

subsequent consumption occasion. Our use of both a food cue internal to the

subsequent consumption situation (study 3A) and a food cue external to the

subsequent consumption situation (study 3B) allows us to generalize the scope of the

process beyond one particular cue that has been shown to increase consumption.

40

Based on prior literature (Federoff et al. 2003; Wansink 2004) we expected

these cues (convenience and scent) to increase consumption in the control condition

because they increase the salience of the cued food. Literature is unclear about

whether we should expect a further increase in consumption in the Non-actionable

Temptation condition as a result of the joint effects of two stimulating cues (i.e. non-

actionable food temptation and the manipulated stimulating cue such as convenience

(study 3A) or scent (study 3B)). We leave this as an explorative question.

STUDY 3A

Method

Participants were 201 female undergraduate students (age between 18 and 26)

who participated in partial fulfillment of a course requirement.

Temptation manipulation. The temptation manipulations were identical to

those used in study 1. Because the effects of the two actionable food temptations did

not differ in the previous studies, we kept only the delayed actionable food temptation

condition. We chose this condition to ensure that no one consumed some of the

candies before the taste test.

Consumption task. After completing the knowledge task and before

participants had the opportunity to eat the ‘Quality Street’ candy, they received the

second task (i.e., a taste test). Participants were given two bowls of the same volume,

one with regular M&Ms (400 grams), and the other with the ‘new’ crispy M&Ms

(300 grams). They were told that they were participating in a comparative taste test of

both types of M&Ms. The participants were allowed to eat as many of the M&Ms as

they needed to evaluate the M&Ms on several dimensions (e.g., ‘are they crunchy?’,

‘are they hard to resist?’, ‘do they have an appetizing aftertaste?’, and ‘do they have

an intense flavor?’).

Convenience manipulation. The convenience of the M&Ms was manipulated

in the taste test. In the Low Convenience condition, the two bowls M&Ms were high

and long (i.e., volume: 530 cm³, surface: 63.6 cm²). In the High Convenience

41

condition, the M&M’s were served in a large dish (i.e., volume: 530 cm³, surface:

180.0 cm²), which made them more convenient to grab. In the Control condition, we

expected to replicate the typical convenience effect (Painter et al. 2002; Schachter,

Friedman, and Handler 1974; Wansink 2004; Wing and Jeffery 2001) namely that

participants would consume more in the High Convenience condition than in the Low

Convenience condition.

Measurements. After the taste test, the bowls were removed, and the

experimenter weighed how many grams of M&Ms had been consumed. Finally,

participants had to indicate how much they liked M&Ms and ‘Quality Street’ candy

(on a scale ranging from 0 to 100), which allowed us to exclude participants from the

analyses who state, by responding ‘0’, that they really do not like one of both. We also

asked them how much time had elapsed since their last food intake before entering the

lab, as a proxy of their hunger level.

Results and discussion

The 201 participants were screened by asking whether they liked M&Ms and

‘Quality Street’ candy. This screening procedure excluded 14 women who did not like

the candy (n = 11) or the M&Ms (n = 3). Additionally, three outliers (i.e., 1.6%,

defined as deviating at least three standard deviations from the mean in their

respective conditions) were removed from the remaining 187 participants, leaving 184

participants in the analyses.

Quantity consumed. An ANCOVA testing the effects of Temptation and

Convenience on the consumed quantity of M&Ms (in grams), with liking for M&Ms

(ranging from 1 to 100, M = 60.66, SD = 24.49) as a covariate, revealed a significant

main effect of Temptation, F(2, 177) = 6.81, p < .002. Moreover, the interaction

contrast between the Control condition and the two temptation conditions combined

(cell combination: [a + (d+f)/2] – [b + (c+e)/2] was significant: F (1, 177) = 3.85, p =

.05 (see figure 2.2). Participants in the Control condition consumed more in the High

Convenience condition (M = 17.72, SD = 13.65) than in the Low Convenience

condition (M = 11.19, SD = 9.84), F(1, 177) = 6.58, p < .02, showing that the

convenience manipulation was successful. As predicted in hypothesis 4, consumption

in the Low Convenience condition was higher in the Non-Actionable Food

42

Temptation (M = 18.04, SD = 12.51) compared to the Control condition (M = 11.19,

SD = 9.84; F(1, 177) = 7.10, p < .009) and to the Delayed Actionable Food

Temptation condition (M = 11.92, SD = 7.75; F(1, 177) = 5.17, p < .03. In addition,

the consumption level of the Actionable Food Temptation condition was comparable

to that in the Control condition (F < 1). Consumption in the High Convenience

condition was lower in the Actionable Food Temptation condition (M = 11.10, SD =

7.07) compared to the Control condition (M = 17.72, SD = 13.65; F(1, 177) = 5.90, p

< .02) and to the Non-Actionable Food Temptation condition (M = 19.32, SD = 13.01;

F(1, 177) = 8.49, p < .005). In other words, the preceding actionable food temptation

suppressed the increase in consumption due to a high convenience of the food cue,

supporting hypothesis 3. In the Non-Actionable Food Temptation condition,

consumption increased regardless of the convenience level.

FIGURE 2.2

Consumption as a function of temptation and convenience, study 3A, with “NFT”: No

Food Temptation, “NAFT”: Non-Actionable Food Temptation and “DAFT”: Delayed

Actionable Food Temptation.

11,19

18,04

11,92

17,72

19,32

11,10

0

5

10

15

20

25

NFT NAFT DAFT

Co

nsu

med

gra

ms M

&M

s

Normal

Convenient

a

b c d

e f

43

STUDY 3B

Method

Participants were 251 female undergraduate students (age between 17 and 33)

in partial fulfillment of a course requirement or in exchange for €6.

Scent manipulation. In order to activate the eating goal, we exposed

participants to the scent of freshly baked brownies. When participants entered, the lab

was filled either with a scent of brownies (i.e., the Scent condition), or with a neutral

scent (i.e., the No Scent condition). Prior research (Fedoroff et al. 2003; Lambert and

Neal 1992) has shown that exposure to an olfactory food cue, here the scent of

brownies, induces craving, liking, and desire to eat the cued food (i.e., cake and

chocolate).

Temptation manipulation. The temptation manipulations were identical to

those used in study 3A.

Consumption task. Right after the temptation manipulation and before

participants had the opportunity to consume the candy, they received the consumption

task, which was identical to the taste test in study 3A, serving the M&Ms in the bowls

used in the low convenience condition of that study. We opted for the low

convenience bowls in order to prevent possible ceiling effects. In other words, we

used the low convenience bowls to disentangle the effect of the appetizing scent in the

most efficient way, independent from the convenience effect. This taste test was

conducted as soon as possible in the experimental session to prevent participants to

adapt to the scent (Morrin and Ratneshwar 2003), which would eliminate its

appetizing effect.

Measurements. As in study 3A, we measured how many grams of M&Ms had

been consumed, how much they liked M&Ms and ‘Quality Street’ candy and how

much time had elapsed since their last food intake before entering the lab.

Results and discussion

The screening procedure led us to exclude eight women who did not like the

candy (n = 6) or the M&Ms (n = 2). Additionally, 4 outliers were removed (i.e., 1.6

44

%, defined as deviating at least three standard deviations from the mean in their

respective conditions), leaving 239 participants in the analyses.

Quantity consumed. A Temptation by Scent ANCOVA on the consumed

quantity of M&Ms (in grams) with liking for M&Ms (ranging from 1 to 100, M =

63.22, SD = 23.53) as a covariate revealed a significant two-way interaction (see

figure 2.3) between Scent and Temptation, F(2, 232) = 3.42, p < .04. In the Control

condition, participants in the Scent condition (M = 24.03, SD = 18.00) consumed

more than in the No Scent condition (M = 14.60, SD = 8.78), F(1, 232) = 9.03, p <

.003, which validates the appetizing effect of the olfactory cue. In the No Scent

condition, the Non-Actionable Food Temptation (M = 21.92, SD = 20.43) increased

consumption compared to the Control condition (M = 14.60, SD = 8.78; F(1, 232) =

4.74, p < .04) and to the Actionable Food Temptation condition (M = 14.95, SD =

10.67; F(1, 232) = 4.16, p < .05), supporting hypothesis 4 and replicating the effects

found in study 3A. The consumption level of the Actionable Food Temptation

condition was comparable to that in the Control condition (F<1). In the Scent

condition, the Actionable Food Temptation condition (M = 14.90, SD = 10.20)

decreased consumption compared to the Control condition (M = 24.03, SD = 18.00;

F(1, 232) = 6.95, p < .009) and to the Non-Actionable Food Temptation condition (M

= 20.38, SD = 17.64; F(1, 232) = 2.74, p < .10), again supporting hypothesis 3. These

results are remarkably similar to the findings of study 3A (see figure 2.3). Again, a

preceding actionable food temptation seemed to inhibit the increase in consumption

due to an appetizing scent found in the Control condition. In the Non-Actionable Food

Temptation condition, consumption increased independent of the scent manipulation.

Taken together, these results suggest that, in support of hypothesis 3, the actionable

food temptation treatment effectively suppressed the consumption increase that

typically accompanies an olfactory cue.

45

FIGURE 2.3

Consumption as a function of temptation and scent, study 3B, with “NFT”: No

Food Temptation, “NAFT”: Non-Actionable Food Temptation and “DAFT”: Delayed

Actionable Food Temptation.

14,6

21,92

14,95

24,03

20,38

14,9

0

5

10

15

20

25

NFT NAFT DAFT

Co

nsu

med

gra

ms M

&M

s

No Scent

Scent

GENERAL DISCUSSION

This article investigated whether food temptations, differing in actionability

(i.e., the opportunity to consume the temptation; pictures of candy vs. a bowl of

candy), encourage or prevent self-control of food intake. In study 1A, we found that

all the food temptations, independent of their actionability, directly activated a food

restriction goal (Fishbach et al. 2003; Shiv and Fedorikhin 2002; Shiv et al. 2005),

supporting H1. In contrast to H2, study 1B showed that the eating goal was activated

in all food temptation conditions. Therefore, a second study tested whether this effect

is due to the incorrectness of our proposed model or the requirement an additional

food threat in the second phase to exceed the critical level of threat. The results show

that, indeed, the pre-exposure to actionable food temptations (i.e., real candy)

prevents the activation of the eating goal when a subsequent food threat is offered.

This additional self-control threat is necessary to trigger the threat detector. Non-

actionable food temptations (i.e., pictures of candy) offer no threat to self-control and

thus do not enhance the surpassing of the critical level by the second actionable food

threat. In the third and last study, we tested whether this also results in self-control

46

enhancement in real subsequent consumption situations. The results show that women

consume more after exposure to a non-actionable food temptation than after exposure

to an actionable food temptation. Moreover, exposure to an actionable food

temptation suppresses the effect of cues that have been shown to increase

consumption; internal (i.e., convenience in study 3A) and external (i.e., an olfactory

cue in study 3B) to the subsequent consumption opportunity. In both studies,

consumption increased after exposure to non-actionable food temptations,

independent of the convenience or scent manipulation.

In sum, exposure to actionable food temptations creates a threat to the long-

term goal of being in good shape which activates the threat detector (figure 2.1) when

a new food threatening food opportunity is encountered. This type of occasion pushes

the consumer beyond the critical level of this threat to the long-term goal, which

triggers self-control strategies The activation of the food restriction goal that resulted

from exposure to these food cues together with the new opportunity to eat will result

in self-control enhancing strategies reflected in the prevention of the activation of the

eating goal. The prevention of the activation of the eating goal results in self-control

enhancement on the consumption occasion that constituted the second threat. This is

consistent with the prediction derived from Gilbert et al. (2004) that exposure to food

temptations can result in self-control enhancement (i.e., food intake control) when the

critical level beyond which self-control strategies are triggered is exceeded.

Moreover, Fishbach et al. (2003) stated that the exposure to temptations might be

more efficient in activating the overriding goal and thus enhancing self-control in

comparison to the direct activation of that goal. Our data are consistent with this

finding. Indeed, exposure to goal-related stimuli creates no self-control threat and

according to our model, does not suffice to reach the critical level. Therefore, the

critical level is not exceeded when a subsequent self-control threat emerges and thus

self-control strategies are not triggered. In addition, Fishbach and Shah (2006) already

suggested that self-control success (i.e., when the original tendency to approach food

stimuli is overridden by the tendency to avoid the stimuli) is enhanced by the strength

of the temptation. In other words, a food temptation should create enough self-control

conflict. Our findings complement the research by Fishbach (2003; 2006) by stating

that the activation of the food restriction goal that resulted from exposure to these

food cues will result in self-control enhancing strategies by preventing the activation

47

of the goal to eat. In addition, this tendency to approach food is overridden only when

the critical level of threat is exceeded. Thus, in contrast to our initial predictions,

actionable food temptations are not sufficient to reduce the activation of an eating

goal but an additional threatening food cue is necessary. This pattern of findings hints

at a process that needs a double input: an initial food temptation that makes the system

sensitive to a subsequent threatening food offer. In this way self-control strategies are

triggered that help to resist that food offer. Only in these circumstances the activation

of the eating goal is overridden. This raises some interesting research questions which

will be discussed in the future research section.

It is important to note that we do not claim that food temptations never lead to

self-control loss. As already mentioned, numerous research showed that consumers

loose their self-control when food is made more salient (Chandon and Wansink 2002;

Fedoroff et al. 2003; Lambert and Neal 1992; Painter et al. 2002; Schachter 1971;

Shiv and Fedorikhin 2002; Wansink 1994; Wansink 1996). Our contribution consists

of providing evidence that salient actionable food cues can lead to self-control

enhancement when the self-control conflict that these cues create in threatening the

pursuit of an opposing long-term goal exceeds the critical level. In other words, this

suggests that the food cues in previous research may not have exceeded such a critical

level and that strongly tempting food cues, that exceed this critical level, offering the

opportunity to consume may better help consumers to control their eating behavior

than weaker tempting food cues that do not exceed the critical level of threat.

We also note that our findings are inconsistent with two alternative

explanations. The first is derived from the self-control strength theory (e.g.,

Baumeister et al. 1998; Vohs and Heatherton 2000), which states that the exertion of

self-control during a first task (e.g., resisting food temptations) leads to self-control

failure in a subsequent task (e.g., overconsumption in a taste test). This theory implies

that participants in the Delayed Actionable Food Temptation condition, which is

depleting because they need to resist the candy, should eat more M&Ms in the

subsequent taste test. The results of studies 3A and 3B yield the opposite pattern,

rejecting ego depletion as an alternative explanation.

48

The other alternative explanation is based on self-perception theory (Bem

1972). The participants may have inferred their self-control capacity on the basis of

their own behavior in the first phase. In the Non-Actionable Food Temptation

condition, they could not eat the ‘Quality Street’ candy and hence they could not infer

anything about their self-control capacity. In the Delayed Actionable Food

Temptation condition, however, they could have eaten the candies (although they had

been urged not to). Their compliance with the request not to eat the candies may have

strengthened these participants’ belief that they were in control of their own

consumption level. The attribution of successful regulatory control (Bem 1972) may

have made it easier for them to resist the subsequent temptation. However, the

Delayed Actionable Food Temptation condition did not differ from the Immediate

Actionable Food Temptation condition in which this instruction was not present.

Moreover, in study 1B, exposure to actionable food temptations activated the goal to

eat which is inconsistent with the self-perception explanation because believing that

you control food intake should not result in the activation of an eating goal.

IMPLICATIONS AND FUTURE RESEARCH

Our results support the counterintuitive idea that advertisements featuring food

temptations might be more of a lure into overconsumption in food opportunities

subsequent to the exposure to the temptation, than placing food right in front of

women. The mechanism behind these effects seems to be that pictures of food are not

seen as a threat and subsequently lead to self-control loss whereas the opportunity to

consume food threatens the achievement of the long-term to be healthy or slim. If this

threat exceeds the critical level, it stimulates the prevention of the activation of the

eating goal, which helps women to maintain their control over their food intake. The

exact dynamics of how and when the critical level is reached needs to be explored

further in subsequent research. How threatening should the temptation be in order to

trigger self-control strategies? Or is it necessary to have two consecutive food

temptations and thus two consecutive self-control conflicts? In this view, it could be

interesting to compare the effects of food temptations differing in salience, namely a

few candies versus a lot of candies. Such a study may reveal the required amount of

food that is required to exceed the critical level. Furthermore, it might be interesting

49

to explore whether the self-control enhancing effect of exposure to actionable food

cues can attenuate the typical preference of affect-laden (e.g., chocolate) over less

affect-laden food (e.g., fruit) (cf. Shiv and Fedorikhin 1999, 2002). We predict that

pre-exposure to an actionable food temptation before the choice between both options

is given, will attenuate the effects found in Shiv and Fedorikhin’s research (1999,

2002), like we found in our studies 3A and 3B. Strictly, our results are also only

generalizable to female students. Generalization to men, and to other age groups, also

remains a matter for further research.

Future research should also explore the role of the similarity between the food

in the two phases and the effect of the two types of temptations (actionable and non-

actionable). In our research, similarity between the food of phase 1 and phase 2 was

high but not perfect. However, the slight difference between the temptation and the

consumption domain testifies to the relevance and strength of our effects. Indeed,

exposure to a food temptation, actionable or non-actionable, influences the consumed

amount of any tempting (unhealthy) food, even if it is dissimilar from the initial

temptation, offered at a later point in time. The fact that the effects were obtained for

slightly differing domains implies that our findings would in all probability also be

obtained if the domains would be identical. However, we are less certain what would

happen when dissimilarity would be higher (e.g. chocolate and cake; chocolate and

pizza, or even chocolate and coke). We know from previous research (Fedoroff et al.

2003; Lambert and Neal 1992) that exposure to the appetizing scent of food, induces

craving, liking, and consumption of the cued food. However, if the offered food (i.e.,

pizza resp. cookies) differed more strongly from the cued food (i.e., cookies resp.

pizza), the effects were not found. These findings imply that exposing consumers to a

non-actionable pizza temptation would lead them to consume more pizza-related food

but not more pizza-unrelated food because the initial non-actionable pizza temptation

induces a desire to eat pizza. For non-actionable temptations then, high similarity

seems to be a requirement. However, for actionable temptations prior literature is less

clear about the role of similarity between the food items in the two phases. Exposure

to an actionable pizza temptation might help consumers to control the consumption of

pizza-related as well as pizza-unrelated food because of the general initial activation

of strategies to solve the self-control conflict. This initial activation pushes consumers

50

beyond the critical level of threat by the second self-control conflict, even if this

concerns a food cue unrelated to the first food cue.

Finally, we call for future research that explores to what extent the effect of the

actionable temptation depends on the success at food restriction. Some research

suggests that tasting a little bit of a food temptation could be a successful inhibitor of

the urge to eat for binge eaters (Jansen 1998). As a result, small transgressions against

the personal norm of rational food intake may push the consumer beyond the critical

level and in this way lead to the enhancement of food intake control. However, the

disinhibition effect (Cochran and Tesser 1996; Polivy and Herman 1985) suggests that

small transgressions may also break down inhibition and hence food intake control.

When people exceed the caloric limit they set for themselves for any given day,

people tend to stop restraining their food intake for that specific day and overindulge

because the day is already lost, also called the what-the-hell-effect. If consumers

would succumb to the actionable food temptation, they may overconsume the food

offered at a later point in time because they already lost control by consuming the

food temptation. Assuming that the consumption of a small amount of the food

temptation should at least be equally threatening as having the opportunity to

consume the food, we expect that tasting a small amount of the actionable food

temptation does not lead to self-control loss in a subsequent consumption opportunity.

However, based on prior literature documenting the what-the-hell-effect large

amounts may lead to the interpretation that ‘this day is lost anyway’ and thus self-

control loss.

Together, our results imply that advertisements showing pictures of tempting

food increase women’s food consumption. However, tempting these consumers with

real food helps them in controlling their food intake when the critical level of threat is

exceeded. Having candy in large stocks at home thus might help women in their

attempts at controlling their food intake, whereas seeing pictures of food in magazines

or on television might lead them to eat more when given the occasion.

51

MANUSCRIPT III:

DEFEAT TEMPTATIONS AND GROW IN SELF-

CONTROL

ABSTRACT

This paper examined how the exertion of self-control in one conflict situation

influences the success of self-control exertion in a subsequent similar self-control

requiring situation. Consistent with the cognitive control theory, which claims that the

well-established reduction in self-control performance following prior exertion of

self-control (the so-called ego depletion effect) is a consequence of people’s

adaptation to situational demands, we show that typical depletion effects occur only

when the nature of the response conflict in the two subsequent tasks is different.

When the nature of the response conflict in the two subsequent tasks is similar, we

found that exerting self-control improves subsequent self-control performance. In

other words, we showed that a state of depletion that was caused by inhibiting food

intake subsequently improved self-control performance in the domain of food intake

control.

52

Consider you need to choose a dish for lunch and you have the choice between

a salad and a hamburger. This situation exposes you to a common conflict between

the short-term desire of wanting an unhealthy snack (i.e., the hamburger) and the

long-term goal to remain healthy or physically attractive which can be obtained by

choosing the health snack (i.e., the salad). In order to resist the hamburger and

maintain the achievement of long-term goals, the exertion of costly self-control efforts

is required. However, according to previous research (Baumeister et al. 1994; Carver

and Scheier 1998; Tice et al. 2001), some individuals are able to resist the short-term

need to indulge in temptations or cravings, whereas others succumb to them. Many of

us often end up with the hamburger because the strength to control themselves is

lacking. More in general, we can state that self-control is lost when the desire for a

given immediate behavior (e.g., eating) is greater than the consumer’s willpower to

achieve long-term goals (e.g., food intake control) (Hoch and Loewenstein 1991;

Loewenstein 1996; Metcalfe and Mischel 1999). In other words, short-run cravings

often prevent people from pursuing their long-term goals.

Substantial research (for a review, see Vohs and Baumeister 2004) showed

that the exertion of self-control in a first phase reduces self-control performance in a

subsequent self-control task. For example, it has been shown that responses such as

thought control (Muraven, Tice, and Baumeister 1998), emotional regulation

(Baumeister et al. 1998), response inhibition (Wallace and Baumeister 2002), repeated

choosing (Bruyneel et al. 2006), intellectual performance (Schmeichel, Vohs, and

Baumeister 2003), food intake control (Vohs and Heatherton 2000), and self-

presentation (Vohs, Baumeister, and Ciarocco 2005) involve reduced performance on

a subsequent self-control task. In the current article we will focus on the role of

similarity between the two subsequent self-control tasks. In other words, we will

examine how the exertion of self-control in one conflict situation influences the

success of self-control exertion in a subsequent similar self-control requiring situation.

The remainder of this paper is organized as follows. We first review the

literature suggesting that self-control exertion taxes a limited resource which leads to

reduced self-control performance in a subsequent self-control task (i.e., the ego-

depletion theory) (e.g., Muraven and Baumeister 2000). Next, some findings from

cognitive neuroscience (i.e., the cognitive control theory) (Botvinick et al. 2001;

53

Miller and Cohen 2001) are discussed, which suggest that self-control exertion can

enhance self-control performance on a subsequent similar self-control task. This view

is consistent with some recent findings that exposure to temptations that threaten the

achievement of a long term goal facilitates the activation level of a construct

representing a potentially obstructed goal (Fishbach et al. 2003) and subsequent self-

control performance on a similar task (manuscript II). After briefly reviewing the ego-

depletion effect and two theories that may explain the effect (i.e., the self-control

strength model; Muraven and Baumeister 2000; and the cognitive control theory;

Botvinick et al. 2001) we will derive divergent predictions from both theories

concerning the performance at consecutive self-control tasks involving similar

response conflicts. The self-control strength model predicts a deterioration of self-

control performance, whereas the cognitive control model predicts an improvement.

After testing the divergent predictions, we conclude the paper with drawing

theoretical implications from our results and sketching some future research

opportunities.

THE SELF-CONTROL STRENGTH MODEL

The ego-depletion literature states that exerting self-control taxes a limited

resource that is akin to energy or strength, and thus brings people in a state of resource

depletion (Muraven and Baumeister 2000). This state reduces people’s capacity to

exert self-control in the next phase.

Studies documenting the depletion effect (Vohs and Baumeister 2004)

typically comprise two phases. In a first phase, half of the people face a situation that

requires them to exert self-control and half do not. In the second phase, people are put

in another situation that requires them to exert self-control (e.g., Baumeister et al.

1998). The robust finding is that self-control performance suffers in the second phase

for those people who exerted self-control in the first phase relative to those who did

not exert self-control in the first phase. Taken together, these studies yield an

impressive set of behaviors (e.g., response inhibition (Wallace and Baumeister 2002)

and food intake control (Vohs and Heatherton 2000) that appear to rely on the scarce

resource that is needed in self-control exertion.

54

THE COGNITIVE CONTROL MODEL

Cognitive control refers to the remarkable ability of the cognitive system to

perform well at specific tasks through adjustments in perceptual selection, response

biasing, and the on-line maintenance of contextual information (Botvinick et al.

2001). Cognitive control theory (Botvinick et al. 2001; Miller and Cohen 2001)

claims that people have a system that monitors ongoing responses and identifies

instances of response conflict, signaling the need for adjustments in control (e.g.,

Carter et al. 1998; Gehring and Fencsik 2001; van Veen and Carter 2002). The

detection of conflict is an important function of a particular area of the human frontal

lobe, namely, the anterior cingulate cortex (ACC). Indeed, in the brain literature at

large, the ACC activation has been found to be highest in situations where the demand

for control is likely to be high, like the overcoming of a strong habitual response,

resistance to temptation, engaging in novel sequences of actions, and troubleshooting

(Shallice and Burgess 1993). Once a conflict is detected, which activates the ACC, the

second, regulatory system, which induces top-down control-related processes to

become actively involved in potentially challenging situations, is alerted. This

guidance of behavior by internal states or intentions is executed through the prefrontal

cortex (PFC). The PFC actively maintains patterns of activity that represent goals and

the means to achieve them. In this way, the PFC guides task performance and

increases the likelihood that the intended response is activated while unintended

responses are inhibited (e.g., Botvinick et al. 2001; Carter et al. 2000; Kerns et al.

2004). Patterns of activity in the PFC configure processing in other parts of the brain

in accordance with current task demands. Control is adjusted on-line, in response to

variations in performance.

The most studied example of task-induced adjustments in control is the classic

Stroop conflict paradigm (Stroop 1935). The Stroop task consists in naming the ink

color in which a color word is displayed. The ink color of the word and the word

meaning can be matched (e.g., the word ‘red’ written in red ink) or mismatched (e.g.,

the word ‘red’ written in green ink). The standard pattern which is observed in this

experimental situation is a higher reaction time for incongruent words, called

interference. According to the cognitive control model (Botvinick et al. 2001; Miller

and Cohen 2001), word-reading is a strong habitual response. Color-naming, on the

55

other hand, is a weaker response, but it should override the stronger word-reading

response if the participant is to comply with the task instructions. The capacity to

override the dominant response (i.e., word-reading) is supported by the activation of

the PFC that maintains the appropriate task-relevant goal and inhibits the automatic

reading association. Moreover, the degree of interference from word reading on color

naming depends on the frequency of incongruent trials, with less interference

occurring when incongruent trials are frequent (e.g., Tzelgov, Henik, and Berger

1992). The occurrence of incongruent trials leads people to selectively attend to one

attribute and focus more effectively on the color-naming task, enhancing their ability

to avoid interference from the word-reading response. This is because incongruent

trials involve a lot of conflict, which triggers activity in the ACC and hence in the

PFC (Botvinick et al. 2001). One of the most fundamental aspects of cognitive control

and goal-directed behavior in general is the ability to select this weaker, task-relevant

response over the stronger, but task-irrelevant response (Miller and Cohen 2001).

Cognitive control theory claims that this ability relies on the detection of response

conflict and the subsequent recruitment of control processes.

However, and very relevant for our current purposes, the recruitment and

deactivation of cognitive control is a gradual process that is characterized by a degree

of inertia (Botvinick et al. 2001). Miller and Cohen (2001) asserted that the PFC must

maintain the task-relevant information in the face of intervening, irrelevant, and

potentially interfering events. This activation of the rules necessary to perform the

task often extends beyond the eliciting event. The sustained activity in the PFC

reduces the flexibility of the PFC for a while which will deteriorate task performance

when the task is preceded by a task involving a different response conflict that

requires control processes to be successful.

Applied to self-control, cognitive control implies that adapting to self-control

situations involves a fine-tuning of one’s response set to increase the fit with the

current situational demands (Miller and Cohen 2001). For instance, adapting to a

traditional Stroop task implies learning to ignore the feature that is dominant as a

result of more extensive and consistent use (i.e., the word meaning) and focusing on

the feature that is subdominant as a result of less extensive and consistent use (i.e., the

word color). In the first trials, the response conflict is intense: the response that wins

56

the race is the wrong one. As the individual learns to ignore the dominant but

irrelevant dimension, the response conflict weakens and performance improves.

THE SELF-CONTROL STRENGTH MODEL AND THE COGNITIVE

CONTROL MODEL.

Task circumstances that have been identified as involving a high demand for

control require planning, decision-making, troubleshooting, the overcoming of a

strong habitual or emotional response, or resisting temptation. They might also be ill-

learned or contain novel sequences of actions, or be technically difficult (Shallice and

Burgess 1993; Norman and Shallice 1986). Interestingly, both the cognitive control

theory (e.g., Botvinick et al. 2001) and the self-control strength theory (e.g., Vohs and

Baumeister 2004) refer to these very task characteristics when theorizing about

cognitive control and self-control, respectively.

The previous sections showed that the vast number of depletion effects that

have been reported in the literature (for an overview, see Vohs and Baumeister 2004)

concerned a sequence of two such tasks involving a high demand. We argue that the

deterioration in self-control performance from task 1 to task 2 that is typically

observed can be reconciled by both the self-control strength theory and the cognitive

control theory. It is well-known that self-control strength theory claims that exerting

self-control in phase 1 consumes a scarce resource, resulting in a reduction in people’s

capacity to exert self-control in phase 2. The explanation according to the cognitive

control model is slightly different. Exerting self-control in phase 1 gears the PFC

towards one particular response set that matches the current tasks demands. In this

process, the PFC temporarily looses some of its flexibility that is required to quickly

adjust to the demands of the task in phase 2. So in the traditional depletion paradigm,

in which two different self-control tasks follow each other, both models can explain

the observed behavior: self-control performance deteriorates from phase 1 to phase 2.

We use the term ego depletion to refer to this well-established phenomenon.

However, when the models are exported to a new situation in which two subsequent

self-control tasks involve similar response conflicts, the two models start to produce

sharply diverging predictions.

57

Cognitive control model predictions

ACC activation has been associated with tasks involving various types of

conflict (e.g., tasks calling for the overriding of relatively automatic but task-

inappropriate responses involve conflict between processing pathways leading to

correct (but usually weaker) and incorrect (but usually strong) responses). In all cases,

the detection of conflict results in an adjustment of one’s behavior in response to

one’s own performance. Difficulty in the task results in a temporarily more focused,

conservative approach and thus an increase in task performance (Botvinick et al.

2001). This leads to the straightforward prediction that when two similar highly

demanding tasks follow each other, performance will improve from the first phase to

the next.

Self-control strength model predictions

The self-control resource has been shown to underlie various types of

behaviors, such as response inhibition (Baumeister et al. 1998, study 1), thought

suppression (Muraven et al. 1998), or repeated choosing (Bruyneel et al. 2006). In all

cases, it has been suggested that performance on these tasks relies on a scarce

resource. The consumption of this resource reduces people’s ability to exert self-

control in the next phase, even at unrelated self-control tasks. This leads to the

straightforward prediction that when two similar highly demanding tasks follow each

other, performance will deteriorate from the first phase to the next.

THE CURRENT STUDY

The aim of the current study is to test the predictions derived from the self-

control strength model and the predictions derived from the cognitive control model

against each other. We investigated whether continuing to exert self-control in the

same domain either reduces performance (consistent with the self-control strength

model) or enhances performance (consistent with the cognitive control model). We

investigated whether the similarity between the two subsequent tasks moderates the

direction of the depletion effect by keeping the task in phase 1 constant and

58

manipulating response conflict similarity between the self-control tasks in both phases

by manipulating the nature of the task in the second phase.

In the first phase, participants were either tempted with attractive chocolates

but asked not to eat any (e.g., Baumeister et al. 1998, study 1), or were asked to

engage in a non-demanding task. In the second phase, half of the participants were

asked to engage in a difficult anagram in which we measured their persistence in

seconds (Baumeister et al. 1998, study 3). Backed by almost a decade of consistent

findings, the self-control strength model unequivocally predicts that persistence on the

anagram task will reduce in the group that was previously tempted and had to exert

self-control to resist their urge to take a sweet, as compared to the control group. The

cognitive control model provides us with the same prediction. The other half of the

participants was asked to engage in a taste test rather than to solve an anagram in the

second phase of the study. Controlling food intake in a taste test of attractive sweets

requires self-control (e.g., Baumeister et al. 1998, study 1; Shiv and Fedorikhin 1999;

Vohs and Heatherton 2000). It is important to stress that the response conflict that is

evoked in a taste test (“I would like to eat, but I shouldn’t eat too much”) is highly

similar to the response conflict in the first phase (“I would like to eat, but I can’t”).

Nevertheless, any spill over from phase 1 to phase 2 cannot be the result of exercising

or a persistence of instruction effects, because the task and the task instructions differ

substantially across the two phases. For one thing, in the first phase, we ask them not

to eat, whereas in the second task, eating was absolutely required to complete the

central task in a meaningful way.

The self-control strength model predicts that depleted participants will have

more trouble controlling their food intake than the control group, whereas the

cognitive control model predicts that the depleted group will perform better at the

taste test. Performance reflects success at regulating food intake (i.e., low

consumption amounts).

59

Method

Participants

One hundred and fifty-two female students participated in exchange for a

participation fee or for course credit. They came to the lab in groups of 4 to 8 people.

We used only women because gender has a major impact on food regulation which is

not the main concern of the current study (e.g., Fishbach et al. 2003).

Procedure

Temptation manipulation. In the High temptation condition, participants were

given a knowledge task on entering the laboratory. Participants were told that the

manufacturer of the chocolate candy brand ‘Quality Street’ was interested in

consumer knowledge of the association between candy flavors on the one hand and

wrap colors and shapes on the other hand. Participants were asked to associate twelve

pictures of the candies (of different colors and shapes) with the corresponding flavor

of each candy (e.g., ‘chocolate with strawberry cream’). In addition, a bowl filled with

lots of these ‘Quality Street’ candies was present next to them. They were told that the

candies were placed there because the pictures were not always very clear. They were

not allowed to eat any candy during the knowledge task, but were told that they were

free to eat as many chocolates as they desired after the knowledge task. In this way,

participants had to exert self-control in order to resist the candies during the

knowledge task. Before participants had the opportunity to eat the ‘Quality Street’

candy after the completion of the knowledge task, the second phase started. During

the first phase of the study, participants in the No temptation condition were asked to

match ten colors with ten concepts (e.g., ‘white’ with ‘snow and ‘green’ with ‘grass’).

The self-control task in the second phase was either similar or dissimilar to the

self-control task in the first phase.

High similarity. In the highly similar self-control task, participants engaged in

a taste test of a relatively unhealthy product. In line with prior research, we consider

restricting consumption in taste tests of unhealthy products as an act of self-control

(e.g., Fishbach et al. 2003; Tice et al. 2001). Participants were given two bowls of the

60

same volume, one with regular M&Ms (400 grams), and the other with the ‘new’

crispy M&Ms (300 grams). They were told that they were participating in a

comparative taste test of both types of M&Ms. The participants were allowed to eat as

many of the M&Ms as they needed to evaluate the M&Ms on several dimensions

(e.g., ‘are they crunchy?’, ‘are they hard to resist?’). After the taste test, the bowls

were removed, and the experimenter weighed how many M&Ms had been consumed.

Low similarity. The low similarity self-control task consisted of untangling an

anagram (Baumeister et al. 1998). Participants received a difficult anagram on

computer. They received 8 characters and had to form appropriate words of at least 7

letters. Only five words were possible and a pretest showed that the majority of the

people found none. The time spent solving the anagram (i.e., a persistence measure)

was recorded.

A pretest in the same population (n = 46) showed that the temptation

manipulation did not affect positive (No temptation; M = 29.7, SD = 6.2; High

temptation; M = 29.0, SD = 6.8, F<1) and negative affect (No temptation; M = 12.9,

SD = 3.9; High temptation; M = 13.2, SD = 4.1, F<1). We preferred measuring affect

in a different sample to preclude participants from consuming the candies of the first

phase during the completion of the affect measure.

Results and discussion

Because the distributions of time spent and quantity consumed were skewed to

the right, both variables were log-transformed. Both dependent measures were

standardized. For the sake of clarity, the quantity consumed was reversed such that

higher values mean better self-control for both self-control tasks. An ANOVA testing

the effects of Temptation and Similarity on the self-control performance measure

revealed a significant interaction between Similarity and Temptation: F(1,149) =

10.07, p < .002 (see figure 3.1). The main effects were not significant (Fs < 0.1). In

the Low similarity condition, tempted people spent less time solving anagrams,

F(1,149) = 4.98, p < .03 (tempted: M = 140s, SD = 136, not tempted: M = 189s, SD =

140). In the High similarity condition, tempted people performed better at the taste

61

test by consuming less, F(1,149) = 5.10, p < .03 (tempted: M = 9.28g, SD = 5.9; not

tempted: M = 13.12g, SD = 7.84).

FIGURE 3.1

Self-control performance (standardized) as a function of the similarity between the

second task (high for the Taste test and low for the Anagram) and preceding level of

food temptation.

The results show that previous exertion of self-control enhances performance

at a second self-control task provided that the second task is similar to the first task

with respect to the response conflict it triggers. At first sight, these findings seem

inconsistent with earlier findings showing that exerting self-control in a food

temptation situation leads to increased consumption in a subsequent food

consumption situation (Vohs and Heatherton 2000, study 1). However, at least for

non-dieters in that study, the trend was consistent with our findings. In the “don’t

touch” condition, putting tempting food at non-dieters’ reach reduced their

consumption compared to putting tempting food out of reach.

-0,3

-0,2

-0,1

0

0,1

0,2

0,3

Anagram Taste test

Second task

Sel

f-co

ntr

ol

per

form

an

ce

High temptation

No temptation

First task

62

GENERAL DISCUSSION

This paper examined how the exertion of self-control in one conflict situation

influences the success of self-control exertion in a subsequent similar self-control

requiring situation. According to the self-control strength theory (Muraven and

Baumeister 2000), performance on tasks involving conflict relies on a scarce resource.

The consumption of this resource reduces people’s ability to overriding one’s

behavior, thoughts, or emotions in a next phase, even at unrelated self-control tasks.

The cognitive control theory (Botvinick et al. 2001), on the other hand, states that

performance on conflict involving tasks improves through temporal adaptation of

one’s behavior to highly demanding situations. Difficulty and conflict in the task

results in a temporarily more focused, conservative approach and thus an increase in

task performance. Although indistinguishable in situations where two unrelated self-

control tasks follow each other (i.e., both models predict a reduction in self-control

performance), the two models yield sharply divergent predictions when applied to a

situation in which two similar self-control tasks follow each other. The self-control

strength model predicts that exerting self-control is depleting, and hence negatively

affects self-control ability in any subsequent situation, irrespective of the similarity

between both types of demand. The cognitive control theory, in contrast, predicts that

response conflicts lead people to temporally adapt to this type of situation, which

should enhance their ability to deal with a subsequent similar response conflict. Our

data provide strong support for the cognitive control model. We showed that a state of

depletion that was caused by inhibiting food intake subsequently improved self-

control performance in the domain of food intake control.

Theoretical Implications

The first implication of our findings is that the ego depletion effect is

moderated by the similarity of the response conflict in the two subsequent self-control

demanding situations. Thereby, similarity is added to the short list of boundary

conditions to the ego depletion effect, in addition to activated beliefs (Martijn et al.

2003), the construction of implementation intentions (Webb and Sheeran 2003), and

high levels of motivation (Muraven and Slessareva 2003). The ego depletion effect

63

occurs only when the response conflict characterizing two subsequent self-control

phases is sufficiently different.

Moreover, our findings suggest exerting self-control in a situation that

involves a certain response conflict appears to facilitate self-control in a subsequent

situation that involves a highly similar response conflict. More specific, inhibiting

food intake in a first phase enhances food intake control in a subsequent taste test. The

implication of these findings is that exerting effort is not a sufficient condition for the

ego depletion effect (in the sense of reduced self-control capacity) to occur. People in

the high similarity conditions had exerted self-control in the first phase but performed

better in the second phase than control participants. Effort does not necessarily induce

depletion. Rather, it may be a side-effect of an adaptive process that helps people to

deal with highly demanding situations.

In addition, according to cognitive control theory, people’s ability to exert

control can be seen as an adaptive process to deal with highly demanding situations.

According to Botvinick et al. (2001), cognitive control has the flavor of strategic

behavior. In each case, individuals adjust their behavioral response to their own

performance. In this way, difficulty leads to a more focused, conservative approach,

whereas ease leads to a slackening of cautiousness or effort. The assessment of

demand for control is evaluated by the occurrence of conflict. Therefore, conflict has

the potential to act as an early warning system, allowing people to deal with problems

before they actually occur. Miller and Cohen (2001) also observed that the conflict

detection system allows people to adapt the degree of control they allocate to a task.

For instance, drivers pay closer attention to the road on a dark and rainy night than on

a bright day. Such adaptive adjustments would correspond to the strength of the PFC

activity. The more signals of conflict detection from the ACC, the stronger the need

for the allocation of additional control and thus the activation of the PFC. That is, in

addition to the regulative dimension of control (through the PFC), there also exists an

evaluative component that monitors information processing (through the ACC),

making an assessment of current demands. In this way, the homunculus (that “just

knows” when to intercede) can be expunged from theories of cognitive control (Miller

and Cohen 2001).

64

Future research

An interesting line for future research pertains to the moderating role of

success at adapting to a particular response conflict. Whenever a response is

successful, reinforcement signals increase the corresponding pattern of activity by

strengthening connections between the PFC neurons that are activated by that

response. Because of this strengthened pathway, task-relevant responses may

eventually gradually become automatic. When this happens, conflict and hence the

need for control diminishes. Activation in the ACC reduces, which is passed on to the

PFC, triggering it to adjust the strength of its influence on processing (Botvinick et al.

2001; Miller and Cohen 2001). Gradually, the PFC becomes irrelevant in the control

of a certain task (e.g., riding a bike, Norman and Shallice 1986). This would imply

that training in resisting tempting food stimuli might be a very effective strategy to

untangle the obesity epidemic. In other words, exposure to strongly tempting food

cues whose resistance requires self-control might be a better in helping consumers

resist them in comparison to safeguarding them from these threatening temptations

(e.g., by offering low-fat snack products).

65

GENERAL DISCUSSION

SUMMARY OF THE FINDINGS

In this dissertation, we investigated how self-control in the domain of food

intake control can be enhanced. The main research question was when environmental

cues hurt or help the exertion of self-control in a subsequent task.

In Manuscript I, we showed that the direct activation of cool nodes (i.e., the

diet/health concept) does not enhance self-control. Indeed, the consumed amount of

regular snack products was not affected by the association with health references.

Moreover, these health references led to self-control loss (i.e., increased consumption)

when they accompany low-fat snack products, probably because they influence the

perceived healthiness of the low-fat snack products (i.e., healthier when accompanied

with health references). Therefore, we examined another possible strategy to enhance

self-control. More specifically, in manuscript II, we investigated whether exposure to

hot, tempting stimuli helps consumers control their food intake on a subsequent

consumption occasion. The results of this second manuscript suggest that, in line with

Fishbach et al. (2003), exposure to actionable food temptations (i.e., hot nodes) can

result in self-control enhancement (i.e., food intake control) when the critical level

beyond which self-control strategies are triggered is exceeded (Gilbert et al. 2004).

Together with the findings of manuscript I, this suggests that the activation of hot

nodes can enhance resistance to subsequent temptations, whereas the activation of

cool nodes does not. According to Fishbach et al. (2003), this difference is explicable

by the fact that temptations activate a narrower set of self-control intentions in

comparison to the direct activation of the goal. The results of our research add that

exposure to threatening food stimuli possibly leads to self-control enhancement when

these threatening stimuli exceed the critical level from which self-control enhancing

strategies are triggered. As shown in manuscript II, self-control is enhanced by the

prevention of the activation of an eating goal. However, the finding that inhibiting

food intake in a first phase subsequently improves food intake control is contradictive

to the ego-depletion literature (Muraven and Baumeister 2000). According to the self-

66

control strength model, the dominant theory in the ego depletion literature, the initial

self-control exertion through resistance of the actionable food temptation should lead

to decreased self-control performance in a subsequent taste test. The examination of

this apparent inconsistency between the main findings of manuscript II and the ego

depletion literature, led to manuscript III. We showed that self-control enhancement in

a taste test was enhanced only if this self-control requiring task was preceded by a

self-control task that was similar in nature (i.e., resisting tempting candies). When the

subsequent self-control task was dissimilar as the self-control task of phase 1 (i.e.,

food intake control in phase 1 and persistence on a difficult anagram task in phase 2),

self-control in the taste test was lost, replicating the effect typically found in the ego-

depletion literature. The cognitive control theory (Botvinick et al. 2001) offers an

appropriate framework for the effects found in manuscript III. According to this

theory, performance on tasks that involve a response conflict improves through

temporal adaptation of one’s behavior to the response conflict. This adaptation

temporarily results in a more focused, conservative approach and thus an increase in

task performance on the present task, and on subsequent tasks with a similar response

conflict. At the same time, this temporary sustained activation of the rules necessary

to perform well on the task deteriorates task performance when the subsequent task

involves a different response conflict. If viable, this theory implies that the ego-

depletion effect (Muraven and Baumeister 2000) occurs only when the response

conflict characterizing two consecutive self-control phases is sufficiently different.

When two similar self-control tasks follow each other, like in manuscript II, self-

control performance in a subsequent similar self-control task is enhanced by the

adjustment to the response conflict that was already induced by the first task. Applied

to the theoretical framework developed in manuscript II, the initial self-control

conflict induced by the exposure to the actionable food cues makes consumers adapt

to the concrete task characteristics by avoiding the consumption of the tempting food.

This initial activation of strategies that help to solve the self-control conflict enables

consumers to successfully activate and use these strategies when a subsequent similar

self-control conflict occurs. In other words, the first activation enables the second

self-control conflict to exceed the critical level of threat. Without the first self-control

conflict, the second temptation would not result in self-control enhancement. An

important implication of this finding is that the exertion of self-control is not always

detrimental to subsequent self-control performance. Quite the contrary, self-control

67

exertion in one conflict situation may enhance self-control performance in a

subsequent situation that requires self-control if these consecutive self-control tasks

involve a similar response conflict.

IMPLICATIONS

Together, the results of the three manuscripts imply that it is better to be

strongly tempted than to be shielded from these threatening temptations (e.g., by

offering low-fat snack products) in order to become better at self-control. The strategy

to stimulate the market penetration of low-fat products in order to reduce overall

caloric intake, as put forward by the WHO (2004), might even worsen instead of

improve the obesity problem if the increase in consumption volume more than offsets

the decreased fat intake due to the lower fat levels in low-fat products. The typical co-

occurrence of these low-fat snack products with health associations might cause these

products to be perceived as healthier and thus less threatening. As we observed in

manuscript I, the association of low-fat snack products with health references results

in increased consumption. For regular snack products no effects of the health

references were found, indicating that the activation of goal-related concepts does not

result in self-control enhancement, but quite the contrary, leads to self-control loss

when combined with low-fat snack products. If this increased consumption translates

to increased absolute caloric intake, the intended caloric reduction might be

counteracted and people might end up consuming as many calories or even more

calories than when they would consume traditional high fat food. This implies that

interventions aimed at reducing fat intake by increasing liking for low-fat foods, along

with increasing the proportion of low-fat food in the household (Raynor et al. 2004)

should be carefully considered. If consumers perceive low-fat snacks products as

being healthier than they really are, they may stimulate consumption. In sum, the

findings of the first manuscript imply that it may be a good idea to control health

references on packages and in ads.

In manuscript II, we found that, as suggested by Fishbach et al. (2003), it

might be better to expose consumers with real actionable food cues (i.e., hot nodes)

instead of exposing consumers to concepts related to food inhibition (i.e., cool nodes)

in order to enhance food intake control. Food cues are threatening to the long-term

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goal of being slim and healthy. When the critical level of this threat to the long-term

goal is exceeded, the activation of the food restriction goal that resulted from

exposure to these food cues will result in self-control enhancing strategies by

preventing the activation of the goal to eat. Non-actionable food temptations (e.g.,

pictures of foods like in ads) are not threatening and thus can not exceed the critical

level of threat. This might explain why the activation of hot nodes is more efficient in

triggering self-control strategies in comparison to the direct activation of cool nodes,

as already suggested by Fishbach et al. (2003). Indeed, exposure to goal-related

stimuli, like in manuscript I, is not threatening. Therefore, the critical level is not

exceeded and thus self-control strategies are not triggered.

Moreover, as suggested by manuscript III, resistance to actionable food

temptations temporarily adapts the consumer’s behavior to the response conflict

caused by the presence of the candies (i.e., the desire to eat and craving for the candy

vs. the goal to comply with the (implicit) situational instructions). In other words,

consumer’s focus will be on successfully performing this self-control demanding task.

The adaptation to the conflict specific to the exposure to the candies enables the task

performance. When a subsequent task involves a similar response conflict, the

previously initiated adaptation to that response conflict will enable performance on

the second task. When a subsequent task involves a different response conflict,

however, the previously initiated adaptation to the dissimilar response conflict will

deteriorate performance on the second task. These findings imply that self-control will

be enhanced when two similar self-control tasks follow each other, like we found in

manuscript II. Together, the findings of manuscripts II and III imply that exposure to

threatening food temptations that require self-control to resist, possibly results in

food-intake control enhancement when a consumption opportunity is offered. This

self-control enhancement implies that the original tendency to crave for the food is

overridden by the tendency to avoid the food stimuli, which threat the continued

pursuit of overarching and opposing goals.

Strongly tempting consumers thus seems to be a more efficient strategy to

combat the obesity epidemic than stimulating the consumption of low-fat products.

However, it is important to note that our data do not allow us to claim that low-fat

snack products are bad. We do support the initiative to produce and offer snacks that

69

contain fewer calories. However, we want to warn for their typical associations with

health. These health associations might influence the health perception of these

products and hence lead to increased consumption. In addition, we note that we do not

claim that food temptations never lead to self-control loss. Numerous researchers

(Chandon and Wansink 2002; Fedoroff et al. 2003; Lambert and Neal 1992; Painter et

al. 2002; Schachter 1971; Shiv and Fedorikhin 2002; Wansink 1994; Wansink 1996)

showed that consumers loose their self-control when food is made more salient. Our

contribution consists of providing evidence that salient actionable food cues can lead

to self-control enhancement when the self-control conflict that these cues create

threatening the pursuit of an opposing long-term goal exceeds the critical level. In

other words, this suggests that the food cues in previous research did not exceed this

critical level and that food cues can better be too tempting in order to help consumers

control their eating behavior. At this point, however, it is not clear how this critical

level is determined, which brings us to the discussion of future research opportunities.

FUTURE RESEARCH AND LIMITATIONS

In the discussion section of each manuscript, we already mentioned possible

future research directions which will be discussed in depth in this section.

Health Primes and Low-fat Snack Products

The results of the first manuscript suggest that it is not efficient to enhance

self-control by directly activating the goal necessary to exert self-control. However,

we investigated the effects of health primes on the consumption of low-fat snacks

offered alone or in the presence of regularly unhealthy snacks. The fact that the

consumed amount of the regular snack product was not influenced by the health

primes (i.e., the lack of effect) might be due to the presence of the low-fat snack

product. It remains possible that the activation of the diet or health goal enhances self-

control in the absence of other options. In this case, the effect of the exposure to goal-

related cues can not affect the perception of the low-fat snack product and thus might

result in the activation of a network of goal-related cool nodes that enhances self-

control. It is clear, however, that the strategy to enhance self-control by activating the

required goal is not efficient for low-fat snack products (manuscript I). On the other

70

hand, this effect deserves further exploration in order to investigate how the

consumption increasing effect of health primes on the consumption of low-fat snacks

works. Is the product indeed perceived as healthier or as an appropriate compromise

for the self-control conflict at hand? Or is there another process possible that was not

yet covered?

One such alternative possibility is that subtle health references might make

people infer that they made substantial progress towards reaching their goal to be

healthy. In other words, the health references might lead consumers to believe that

they made substantial progress towards the goal to be healthy and in this way liberate

them from adhering to the achievement of the goal. Thereby, actions incongruent to

the pursued goal will be more likely undertaken (Fishbach and Dhar 2005). An action

incongruent to the goal of being healthy is increasing consumption, like we found in

manuscript I for the low-fat product. In line with this positioning, some preliminary

evidence suggests that the health primes indeed make people believe that they are

closer to their ideal weight. Additional studies are needed to uncover the process

responsible for the consumption increasing effect of health primes on the consumption

of low-fat snack products.

It has been shown that consumers do ration the purchase quantities of products

that threaten the attainability of long-term goals, in order to solve their self-control

problem (Wertenbroch 1998). This behavior is based on the belief that limiting the

stock of these products reduces the temptation to overconsume them. To reach that

objective, consumers are even prepared to forgo quantity price discounts. An

interesting avenue for future research is to investigate whether these effects also hold

for low-fat snack products. If consumers perceive low-fat products as a threat to their

long-term goals and accordingly restrain the purchase of these products, the effects

would be comparable. However, if consumers experience low-fat products as offering

less or no self-control threat, they could tend to stockpile these products at home.

Given that stockpiling makes people consume convenience products at a faster rate

(Chandon and Wansink 2002), this would imply that low-fat versions of unhealthy

snacks may be more readily stockpiled at home and in this way consumed at a faster

rate. In addition, the health association that is typical of these kinds of snack product

may even strengthen the consumption acceleration.

71

In light of the recent stimulation and promotion of low-fat products, it is

timely to explore the long run effects of the association of low-fat snack products to

health. If the consumption increasing effect found in manuscript I results in increased

absolute caloric intake, people might end up consuming more calories than when they

would consume traditional high fat food. This would imply that the promotion of low-

fat versions is far from efficient in reducing the total caloric intake.

Actionable Food Temptations and the Critical Level

As the findings of manuscript II suggest, there must be some critical level of

threat beyond which self-control is activated. When this level is not yet reached,

exposure to food temptations results in the activation of the goal to eat. Indeed,

recently Fishbach and Shah (2006) also found that the automatic response to food

stimuli is a tendency to approach these stimuli. However, at the same time, especially

for dieters, there is an automatic tendency to avoid these food stimuli. This suggests

that the self-control conflict caused by exposure to actionable food cues emerges by

the simultaneous approach and avoidance tendencies that they induce. Self-control is

successful when the original tendency to approach these stimuli is overridden by the

tendency to avoid the stimuli. Moreover, these food stimuli activate an approach

tendency to the overriding goal, replicating our findings of manuscript II and the

earlier findings of Fishbach et al. (2003). We stated, in manuscript II, that the original

tendency to approach the food stimuli is overridden when the threat of the food

temptation exceeds the critical level. In other words, the temptation should constitute

a significant threat to self-control. In this case, the activation of the eating goal is

overridden. This suggests some interesting ideas for future research. First, it might be

interesting to find out how and when the critical level is reached. How threatening

should the temptation be in order to trigger self-control strategies? Or is it necessary

to have two consecutive food temptations and thus two consecutive self-control

conflicts to achieve the effects found in manuscript II? In this view, it could also be

interesting to compare the effects of food temptations differing in salience, namely a

few candies versus a lot of candies. Such a study may reveal the required amount of

food that is required to exceed the critical level. We also showed (manuscript II) that

the exposure to actionable food temptations prevents consumers to increase

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consumption when they are exposed to convenient food cues or an appetizing scent.

In the same vein, prior research showed that larger package size can increase

consumption (Wansink 1996), as can the increasing size of portion servings in

kitchens and in restaurants (Edelman et al. 1986; Rolls, Morris, and Roe 2002).

Indeed, portions and package sizes have grown larger over the past 30 years (Nielsen

and Popkin 2003; Young and Nestle 2002). Moreover, people rely on visual cues or

rules-of-thumb (such as eating until a bowl is empty) to determine the appropriate

amount to eat. As a result of this rule-of-thumb, the amount of food on a plate or in a

bowl implicitly suggests the “normal” or “appropriate” amount to consume (Fisher,

Rolls, and Birch 2003; Kahn and Wansink 2004). Consequently, we eat often more

without realizing it, thereby doing our part to promote the current obesity epidemic.

The consumption increasing effect of the portion sizes should not be underestimated,

as Wansink, Painter and North (2005) showed that people use their eyes to count

calories and not their stomachs. People consumed dramatically more from refilling

soup bowls than from normal bowls, implying that the amount of food on a plate or

bowl influences the consumption norm independent of people’s monitoring process

that keeps track of how much one is eating. These visual cue increase the amount

eventually consumed. When we combine these effects with those of manuscript II, it

seems interesting to explore whether a certain portion size can exceed the critical level

and in this way curb the consumed amount. In addition, it might be possible that the

self-control conflict caused by the threat of exposure to actionable food cues helps to

control food intake on a subsequent consumption occasion, even when big portions

are offered. Furthermore, it might be interesting to explore whether the self-control

enhancing effect of exposure to actionable food cues can attenuate the typical

preference of affect-laden (e.g., chocolate) over less affect-laden food (e.g., fruit) (cf.

Shiv and Fedorikhin 1999; 2002). In the light of manuscript II, we speculate that the

choice situation offering both healthy and unhealthy options may make the threat

more salient and hence make that the critical level is exceeded. Subsequently self-

control strategies would be triggered which may help consumers to choose the

healthier less affect-laden food option.

73

Success in Overriding the Self-control Conflict

Another opportunity for future research is to explore to what extent the effect

of the actionable temptation depends on the success of the food restriction. Some

research suggests that tasting a little bit of a food temptation could be a successful

inhibitor of the urge to eat for binge eaters (Jansen 1998). As a result, small

transgressions against the personal norm of rational food intake may push the

consumer across the critical level and in this way lead to the enhancement of food

intake control. However, the disinhibition effect suggests that small transgressions

may break down inhibition and hence food intake control. When people exceed the

caloric limit they set for themselves for any given day, people tend to stop restraining

their food intake for that specific day and overindulge because the day is already lost,

also called the what-the-hell-effect (Cochran and Tesser 1996; Polivy and Herman

1985). If consumers would succumb to the actionable food temptation, they might

overconsume the food offered at a later point in time because they already lost control

by consuming the food temptation. According to the theoretical framework of

manuscript II, we suggest that tasting a small amount of the actionable food

temptation does not lead to self-control loss in a subsequent consumption opportunity.

We assume that the consumption of a small amount of the food temptation should at

least be equally threatening than having the opportunity to consume the food. We

have some preliminary results that support this prediction. An interesting question for

future research pertains to the moderators of tasting the temptation. One possibility is

the amount consumed. In prior literature documenting the what-the-hell-effect,

participants had to consume large amounts of high-caloric foods, whereas in our

preliminary data, people typically tasted a small amount. Perhaps small amount are

very efficient in triggering self-control strategies, whereas large amounts may lead to

the interpretation that ‘this day is lost anyway’.

Related to this, another interesting line for future research pertains to the

moderating role of success at adapting to a particular response conflict. Whenever a

response is successful in a certain situation, reinforcement signals increase the

corresponding pattern of activity by strengthening connections between the prefrontal

cortex (PFC) neurons that are activated by that response. Because of this strengthened

pathway, task-relevant responses may eventually gradually become automatic. When

74

this happens, conflict and hence the need for control diminishes. Activation in the

Anterior Cingular Cortex (which detects conflicts and thus the need for control)

reduces, which is passed on to the PFC, triggering it to adjust the strength of its

influence on processing (Botvinick et al. 2001; Miller and Cohen 2001). Gradually,

the PFC becomes irrelevant in the control of a certain task (e.g., riding a bike, Norman

and Shallice 1986). This would imply that training in successfully resisting strongly

tempting food stimuli may be a very effective strategy to untangle the obesity

epidemic.

Low-fat Snack Products and the Critical Level

Another question for future research concerns the effects of initial exposure to

threatening food cues on the consumption of low-fat snack products (e.g., low-fat

chips). Is the additional threat of the low-fat snack product large enough to exceed the

critical level, or does this result in self-control loss and thus increased consumption of

the snack product? Moreover, the low-fat snack product might be perceived as less

threatening due to the previous threat of the unhealthy food. Indeed, previous research

(Huber and Puto 1983; Simonson 1989) shows that an alternative choice probability

tends to increase when it becomes a compromise in the choice set, also called the

compromise effect. In other words, if exposure to unhealthy food temptations makes

low-fat snack products to be perceived as a compromise between the craving for the

unhealthy food temptation and consumption of less appetitive healthy food in order to

pursue the long-term goal to stay in shape, it will receive total preference. Moreover,

if the taste of the regular and the low-fat snack products are perceived as almost

identical, the low-fat snack product might even become the dominant alternative, as

suggested by the attraction effect (Huber, Payne, and Puto 1982; Huber and Puto

1983; Ratneshwar, Shocker, and Stewart 1987). Furthermore, we know from

manuscript II that the eating goal is activated after the first exposure to threatening

food cues. What would happen when the subsequent food cues are healthy? On the

one hand, the activated eating goal should result in an increased consumption of the

healthy food because it is not threatening and can thus offer no additional activation to

exceed the critical level. On the other hand, it is possible that the initial exposure to

the unhealthy food cue activated desire for unhealthy food but not for relatively

75

healthier food. If this is the case, no increase in the consumption of the subsequently

offered healthy food is expected.

Similarity of Consecutive Food Temptations

This brings us to a final research opportunity that deserves further

investigation. Does the exposure to unhealthy food cues activate a general goal to eat

or is this craving limited to the food cue itself? In other words, what is the role of the

similarity between the food in the two phases and the effect of the two types of

temptations (actionable and non-actionable)? In manuscripts II and III, similarity

between the food of phase 1 and phase 2 was high but not perfect. However, the slight

difference between the temptation and the consumption domain testifies to the

relevance and strength of our effects. Indeed, exposure to a food temptation,

actionable or non-actionable, influences the consumed amount of any tempting

(unhealthy) food, even if it is dissimilar from the initial temptation, offered at a later

point in time. The fact that the effects were obtained for slightly differing domains

implies that our findings would in all probability also be obtained if the domains

would be identical. However, we are less certain when dissimilarity would be higher

(e.g., chocolate and cake; chocolate and pizza, or even chocolate and coke). We know

from previous research (Fedoroff et al. 2003; Lambert and Neal 1992) that exposure

to the appetizing scent of food, induces craving, liking, and consumption of the cued

food. However, if the offered food (i.e., pizza resp. cookies) differed more strongly

from the cued food (i.e., cookies resp. pizza), the effects were not found. These

findings imply that exposing consumers to a non-actionable pizza temptation would

lead them to consume more pizza-related food but not more pizza-unrelated food

because the initial non-actionable pizza temptation induces a desire to eat pizza. For

non-actionable temptations then, high similarity seems to be a requirement. However,

for actionable temptations prior literature is less clear about the role of similarity

between the food items in the two phases. Exposure to an actionable pizza temptation

might help consumers to control the consumption of pizza-related as well as pizza-

unrelated food because of the general initial activation of strategies to solve the self-

control conflict. This initial activation pushes consumers beyond the critical level of

threat by the second self-control conflict, even if this concerns a food cue unrelated to

the first food cue.

76

Limitations

We acknowledge that the research methods used in this dissertation limit the

generality of our conclusions. A first limitation concerns the short period of time of

the consumption opportunity, which forces us to be careful in drawing conclusions in

the long-run. The obtained results should serve as initial evidence that deserves

further exploration to investigate the effects in the long-run. Moreover, eating

behavior in a laboratory is not the same as real eating behavior. However, research

concerning the effects of environmental stimuli on food intake mostly uses these

kinds of methods and analyses (Roefs and Jansen 2004; Rotenberg et al. 2005). In

addition, we assume the consumption pattern in the control condition to reflect normal

eating and that the relevant information is in the difference between the control and

the experimental conditions.

Strictly, our results are also only generalizable to women and mainly students.

Generalization across gender, age, and socio-economic status remains a matter for

further research.

77

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16. DAEMS, Herman The holding company: essays on financial intermediation, concentration and capital market imperfections in the Belgian economy. Leuven, K.U.Leuven, 1975. XII, 268 pp.

17. VAN ROMPUY, Eric Groot-Brittannië en de Europese monetaire integratie: een onderzoek naar de gevolgen van de Britse toetreding op de geplande Europese monetaire unie. Leuven, Acco, 1975. XIII, 222 pp.

18. MOESEN, Wim Het beheer van de staatsschuld en de termijnstructuur van de intrestvoeten met een toepassing voor België. Leuven, Vander, 1975. XVI, 250 pp.

19. LAMBRECHT, Marc Capacity constrained multi-facility dynamic lot-size problem. Leuven, KUL, 1976. 165 pp.

20. RAYMAECKERS, Erik De mens in de onderneming en de theorie van het producenten-gedrag: een bijdrage tot transdisciplinaire analyse. Leuven, Acco, 1976. XIII, 538 pp.

21. TEJANO, Albert Econometric and input-output models in development planning: the case of the Philippines. Leuven, KUL, 1976. XX, 297 pp.

22. MARTENS, Bernard Prijsbeleid en inflatie met een toepassing op België. Leuven, KUL, 1977. IV, 253 pp.

23. VERHEIRSTRAETEN, Albert Geld, krediet en intrest in de Belgische financiële sector. Leuven, Acco, 1977. XXII, 377 pp.

24. GHEYSSENS, Lieven International diversification through the government bond market: a risk-return analysis. Leuven, s.n., 1977. 188 pp.

89

25. LEFEBVRE, Chris Boekhoudkundige verwerking en financiële verslaggeving van huurkooptransacties en verkopen op afbetaling bij ondernemingen die aan consumenten verkopen. Leuven, KUL, 1977. 228 pp.

26. KESENNE, Stefan Tijdsallocatie en vrijetijdsbesteding: een econometrisch onderzoek. Leuven, s.n., 1978. 163 pp.

27. VAN HERCK, Gustaaf Aspecten van optimaal bedrijfsbeleid volgens het marktwaardecriterium: een risico-rendementsanalyse. Leuven, KUL, 1978. IV, 163 pp.

28. VAN POECK, Andre World price trends and price and wage development in Belgium: an investigation into the relevance of the Scandinavian model of inflation for Belgium. Leuven, s.n., 1979. XIV, 260 pp.

29. VOS, Herman De industriële technologieverwerving in Brazilië: een analyse. Leuven, s.n., 1978. onregelmatig gepagineerd.

30. DOMBRECHT, Michel Financial markets, employment and prices in open economies. Leuven, KUL, 1979. 182 pp.

31. DE PRIL, Nelson Bijdrage tot de actuariële studie van het bonus-malussysteem. Brussel, OAB, 1979. 112 pp.

32. CARRIN, Guy Economic aspects of social security: a public economics approach. Leuven, KUL, 1979. onregelmatig gepagineerd

33. REGIDOR, Baldomero An empirical investigation of the distribution of stock-market prices and weak-form efficiency of the Brussels stock exchange. Leuven, KUL, 1979. 214 pp.

34. DE GROOT, Roger Ongelijkheden voor stop loss premies gebaseerd op E.T. systemen in het kader van de veralgemeende convexe analyse. Leuven, KUL, 1979. 155 pp.

35. CEYSSENS, Martin On the peak load problem in the presence of rationizing by waiting. Leuven, KUL, 1979. IX, 217 pp.

36. ABDUL RAZK ABDUL Mixed enterprise in Malaysia: the case study of joint venture between Malysian public corporations and foreign enterprises. Leuven, KUL, 1979. 324 pp.

37. DE BRUYNE, Guido Coordination of economic policy: a game-theoretic approach. Leuven, KUL, 1980. 106 pp.

90

38. KELLES, Gerard Demand, supply, price change and trading volume on financial markets of the matching-order type. = Vraag, aanbod, koersontwikkeling en omzet op financiële markten van het Europese type. Leuven, KUL, 1980. 222 pp.

39. VAN EECKHOUDT, Marc De invloed van de looptijd, de coupon en de verwachte inflatie op het opbrengstverloop van vastrentende financiële activa. Leuven, KUL, 1980. 294 pp.

40. SERCU, Piet Mean-variance asset pricing with deviations from purchasing power parity. Leuven, s.n., 1981. XIV, 273 pp.

41. DEQUAE, Marie-Gemma Inflatie, belastingsysteem en waarde van de onderneming. Leuven, KUL, 1981. 436 pp.

42. BRENNAN, John An empirical investigation of Belgian price regulation by prior notification: 1975 - 1979 - 1982. Leuven, KUL, 1982. XIII, 386 pp.

43. COLLA, Annie Een econometrische analyse van ziekenhuiszorgen. Leuven, KUL, 1982. 319 pp.

44. Niet toegekend.

45. SCHOKKAERT, Eric Modelling consumer preference formation. Leuven, KUL, 1982. VIII, 287 pp.

46. DEGADT, Jan Specificatie van een econometrisch model voor vervuilingsproblemen met proeven van toepassing op de waterverontreiniging in België. Leuven, s.n., 1982. 2 V.

47. LANJONG, Mohammad Nasir A study of market efficiency and risk-return relationships in the Malaysian capital market. s.l., s.n., 1983. XVI, 287 pp.

48. PROOST, Stef De allocatie van lokale publieke goederen in een economie met een centrale overheid en lokale overheden. Leuven, s.n., 1983. onregelmatig gepagineerd.

49. VAN HULLE, Cynthia ( /08/83) Shareholders' unanimity and optimal corporate decision making in imperfect capital markets. s.l., s.n., 1983. 147 pp. + appendix.

50. VAN WOUWE, Martine (2/12/83) Ordening van risico's met toepassing op de berekening van ultieme ruïnekansen. Leuven, s.n., 1983. 109 pp.

91

51. D'ALCANTARA, Gonzague (15/12/83) SERENA: a macroeconomic sectoral regional and national account econometric model for the Belgian economy. Leuven, KUL, 1983. 595 pp.

52. D'HAVE, Piet (24/02/84) De vraag naar geld in België. Leuven, KUL, 1984. XI, 318 pp.

53. MAES, Ivo (16/03/84) The contribution of J.R. Hicks to macro-economic and monetary theory. Leuven, KUL, 1984. V, 224 pp.

54. SUBIANTO, Bambang (13/09/84) A study of the effects of specific taxes and subsidies on a firms' R&D investment plan. s.l., s.n., 1984. V, 284 pp.

55. SLEUWAEGEN, Leo (26/10/84) Location and investment decisions by multinational enterprises in Belgium and Europe. Leuven, KUL, 1984. XII, 247 pp.

56. GEYSKENS, Erik (27/03/85) Produktietheorie en dualiteit. Leuven, s.n., 1985. VII, 392 pp.

57. COLE, Frank (26/06/85) Some algorithms for geometric programming. Leuven, KUL, 1985. 166 pp.

58. STANDAERT, Stan (26/09/86) A study in the economics of repressed consumption. Leuven, KUL, 1986. X, 380 pp.

59. DELBEKE, Jos (03/11/86) Trendperioden in de geldhoeveelheid van België 1877-1983: een theoretische en empirische analyse van de "Banking school" hypothese. Leuven, KUL, 1986. XII, 430 pp.

60. VANTHIENEN, Jan (08/12/86) Automatiseringsaspecten van de specificatie, constructie en manipulatie van beslissingstabellen. Leuven, s.n., 1986. XIV, 378 pp.

61. LUYTEN, Robert (30/04/87) A systems-based approach for multi-echelon production/inventory systems. s.l., s.n., 1987. 3V.

62. MERCKEN, Roger (27/04/87) De invloed van de data base benadering op de interne controle. Leuven, s.n., 1987. XIII, 346 pp.

63. VAN CAYSEELE, Patrick (20/05/87) Regulation and international innovative activities in the pharmaceutical industry. s.l., s.n., 1987. XI, 169 pp.

92

64. FRANCOIS, Pierre (21/09/87) De empirische relevantie van de independence from irrelevant alternatives. Assumptie indiscrete keuzemodellen. Leuven, s.n., 1987. IX, 379 pp.

65. DECOSTER, André (23/09/88) Family size, welfare and public policy. Leuven, KUL. Faculteit Economische en Toegepaste Economische Wetenschappen, 1988. XIII, 444 pp.

66. HEIJNEN, Bart (09/09/88) Risicowijziging onder invloed van vrijstellingen en herverzekeringen: een theoretische analyse van optimaliteit en premiebepaling. Leuven, KUL. Faculteit Economische en Toegepaste Economische Wetenschappen, 1988. onregelmatig gepagineerd.

67. GEEROMS, Hans (14/10/88) Belastingvermijding. Theoretische analyse van de determinanten van de belastingontduiking en de belastingontwijking met empirische verificaties. Leuven, s.n., 1988. XIII, 409, 5 pp.

68. PUT, Ferdi (19/12/88) Introducing dynamic and temporal aspects in a conceptual (database) schema. Leuven, KUL. Faculteit Economische en Toegepaste Economische Wetenschappen, 1988. XVIII, 415 pp.

69. VAN ROMPUY, Guido (13/01/89) A supply-side approach to tax reform programs. Theory and empirical evidence for Belgium. Leuven, KUL. Faculteit Economische en Toegepaste Economische Wetenschappen, 1989. XVI, 189, 6 pp.

70. PEETERS, Ludo (19/06/89) Een ruimtelijk evenwichtsmodel van de graanmarkten in de E.G.: empirische specificatie en beleidstoepassingen. Leuven, K.U.Leuven. Faculteit Economische en Toegepaste Economische Wetenschappen, 1989. XVI, 412 pp.

71. PACOLET, Jozef (10/11/89) Marktstructuur en operationele efficiëntie in de Belgische financiële sector. Leuven, K.U.Leuven. Faculteit Economische en Toegepaste Economische Wetenschappen, 1989. XXII, 547 pp.

72. VANDEBROEK, Martina (13/12/89) Optimalisatie van verzekeringscontracten en premieberekeningsprincipes. Leuven, K.U.Leuven. Faculteit Economische en Toegepaste Economische Wetenschappen, 1989. 95 pp.

73. WILLEKENS, Francois () Determinance of government growth in industrialized countries with applications to Belgium. Leuven, K.U.Leuven. Faculteit Economische en Toegepaste Economische Wetenschappen, 1990. VI, 332 pp.

74. VEUGELERS, Reinhilde (02/04/90) Scope decisions of multinational enterprises. Leuven, K.U.Leuven. Faculteit Economische en Toegepaste Economische Wetenschappen, 1990. V, 221 pp.

93

75. KESTELOOT, Katrien (18/06/90) Essays on performance diagnosis and tacit cooperation in international oligopolies. Leuven, K.U.Leuven. Faculteit Economische en Toegepaste Economische Wetenschappen, 1990. 227 pp.

76. WU, Changqi (23/10/90) Strategic aspects of oligopolistic vertical integration. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1990. VIII, 222 pp.

77. ZHANG, Zhaoyong (08/07/91) A disequilibrium model of China's foreign trade behaviour. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1991. XII, 256 pp.

78. DHAENE, Jan (25/11/91) Verdelingsfuncties, benaderingen en foutengrenzen van stochastische grootheden geassocieerd aan verzekeringspolissen en -portefeuilles. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1991. 146 pp.

79. BAUWELINCKX, Thierry (07/01/92) Hierarchical credibility techniques. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1992. 130 pp.

80. DEMEULEMEESTER, Erik (23/3/92) Optimal algorithms for various classes of multiple resource-constrained project scheduling problems. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1992. 180 pp.

81. STEENACKERS, Anna (1/10/92) Risk analysis with the classical actuarial risk model: theoretical extensions and applications to Reinsurance. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1992. 139 pp.

82. COCKX, Bart (24/09/92) The minimum income guarantee. Some views from a dynamic perspective. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1992. XVII, 401 pp.

83. MEYERMANS, Eric (06/11/92) Econometric allocation systems for the foreign exchange market: Specification, estimation and testing of transmission mechanisms under currency substitution. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1992. XVIII, 343 pp.

84. CHEN, Guoqing (04/12/92) Design of fuzzy relational databases based on fuzzy functional dependency. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1992. 176 pp.

94

85. CLAEYS, Christel (18/02/93) Vertical and horizontal category structures in consumer decision making: The nature of product hierarchies and the effect of brand typicality. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1993. 348 pp.

86. CHEN, Shaoxiang (25/03/93) The optimal monitoring policies for some stochastic and dynamic production processes. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1993. 170 pp.

87. OVERWEG, Dirk (23/04/93) Approximate parametric analysis and study of cost capacity management of computer configurations. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1993. 270 pp.

88. DEWACHTER, Hans (22/06/93) Nonlinearities in speculative prices: The existence and persistence of nonlinearity in foreign exchange rates. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1993. 151 pp.

89. LIN, Liangqi (05/07/93) Economic determinants of voluntary accounting choices for R & D expenditures in Belgium. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1993. 192 pp.

90. DHAENE, Geert (09/07/93) Encompassing: formulation, properties and testing. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1993. 117 pp.

91. LAGAE, Wim (20/09/93) Marktconforme verlichting van soevereine buitenlandse schuld door private crediteuren: een neo-institutionele analyse. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1993. 241 pp.

92. VAN DE GAER, Dirk (27/09/93) Equality of opportunity and investment in human capital. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1993. 172 pp.

93. SCHROYEN, Alfred (28/02/94) Essays on redistributive taxation when monitoring is costly. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1994. 203 pp. + V.

94. STEURS, Geert (15/07/94) Spillovers and cooperation in research and development. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1994. 266 pp.

95

95. BARAS, Johan (15/09/94) The small sample distribution of the Wald, Lagrange multiplier and likelihood ratio tests for homogeneity and symmetry in demand analysis: a Monte Carlo study. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1994. 169 pp.

96. GAEREMYNCK, Ann (08/09/94) The use of depreciation in accounting as a signalling device. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1994. 232 pp.

97. BETTENDORF, Leon (22/09/94) A dynamic applied general equilibrium model for a small open economy. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1994. 149 pp.

98. TEUNEN, Marleen (10/11/94) Evaluation of interest randomness in actuarial quantities. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1994. 214 pp.

99. VAN OOTEGEM, Luc (17/01/95) An economic theory of private donations. Leuven. K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1995. 236 pp.

100. DE SCHEPPER, Ann (20/03/95) Stochastic interest rates and the probabilistic behaviour of actuarial functions. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1995. 211 pp.

101. LAUWERS, Luc (13/06/95) Social choice with infinite populations. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1995. 79 pp.

102. WU, Guang (27/06/95) A systematic approach to object-oriented business modeling. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1995. 248 pp.

103. WU, Xueping (21/08/95) Term structures in the Belgian market: model estimation and pricing error analysis. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1995. 133 pp.

104. PEPERMANS, Guido (30/08/95) Four essays on retirement from the labor force. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1995. 128 pp.

105. ALGOED, Koen (11/09/95) Essays on insurance: a view from a dynamic perspective. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1995. 136 pp.

96

106. DEGRYSE, Hans (10/10/95) Essays on financial intermediation, product differentiation, and market structure. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1995. 218 pp.

107. MEIR, Jos (05/12/95) Het strategisch groepsconcept toegepast op de Belgische financiële sector. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1995. 257 pp.

108. WIJAYA, Miryam Lilian (08/01/96) Voluntary reciprocity as an informal social insurance mechanism: a game theoretic approach. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1996. 124 pp.

109. VANDAELE, Nico (12/02/96) The impact of lot sizing on queueing delays: multi product, multi machine models. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1996. 243 pp.

110. GIELENS, Geert (27/02/96) Some essays on discrete time target zones and their tails. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1996. 131 pp.

111. GUILLAUME, Dominique (20/03/96) Chaos, randomness and order in the foreign exchange markets. Essays on the modelling of the markets. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1996. 171 pp.

112. DEWIT, Gerda (03/06/96) Essays on export insurance subsidization. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1996. 186 pp.

113. VAN DEN ACKER, Carine (08/07/96) Belief-function theory and its application to the modeling of uncertainty in financial statement auditing. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1996. 147 pp.

114. IMAM, Mahmood Osman (31/07/96) Choice of IPO Flotation Methods in Belgium in an Asymmetric Information Framework and Pricing of IPO’s in the Long-Run. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1996. 221 pp.

115. NICAISE, Ides (06/09/96) Poverty and Human Capital. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1996. 209 pp.

97

116. EYCKMANS, Johan (18/09/97) On the Incentives of Nations to Join International Environmental Agreements. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1997. XV + 348 pp.

117. CRISOLOGO-MENDOZA, Lorelei (16/10/97) Essays on Decision Making in Rural Households: a study of three villages in the Cordillera Region of the Philippines. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1997. 256 pp.

118. DE REYCK, Bert (26/01/98) Scheduling Projects with Generalized Precedence Relations: Exact and Heuristic Procedures. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1998. XXIV + 337 pp.

119. VANDEMAELE Sigrid (30/04/98) Determinants of Issue Procedure Choice within the Context of the French IPO Market: Analysis within an Asymmetric Information Framework. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1998. 241 pp.

120. VERGAUWEN Filip (30/04/98) Firm Efficiency and Compensation Schemes for the Management of Innovative Activities and Knowledge Transfers. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1998. VIII + 175 pp.

121. LEEMANS Herlinde (29/05/98) The Two-Class Two-Server Queueing Model with Nonpreemptive Heterogeneous Priority Structures. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1998. 211 pp.

122. GEYSKENS Inge (4/09/98) Trust, Satisfaction, and Equity in Marketing Channel Relationships. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1998. 202 pp.

123. SWEENEY John (19/10/98) Why Hold a Job ? The Labour Market Choice of the Low-Skilled. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1998. 278 pp.

124. GOEDHUYS Micheline (17/03/99) Industrial Organisation in Developing Countries, Evidence from Côte d'Ivoire. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1999. 251 pp.

125. POELS Geert (16/04/99) On the Formal Aspects of the Measurement of Object-Oriented Software Specifications. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1999. 507 pp.

98

126. MAYERES Inge (25/05/99) The Control of Transport Externalities: A General Equilibrium Analysis. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1999. XIV + 294 pp.

127. LEMAHIEU Wilfried (5/07/99) Improved Navigation and Maintenance through an Object-Oriented Approach to Hypermedia Modelling. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1999. 284 pp.

128. VAN PUYENBROECK Tom (8/07/99) Informational Aspects of Fiscal Federalism. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1999. 192 pp.

129. VAN DEN POEL Dirk (5/08/99) Response Modeling for Database Marketing Using Binary Classification. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1999. 342 pp.

130. GIELENS Katrijn (27/08/99) International Entry Decisions in the Retailing Industry: Antecedents and Performance Consequences. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1999. 336 pp.

131. PEETERS Anneleen (16/12/99) Labour Turnover Costs, Employment and Temporary Work. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1999. 207 pp.

132. VANHOENACKER Jurgen (17/12/99) Formalizing a Knowledge Management Architecture Meta-Model for Integrated Business Process Management. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 1999. 252 pp.

133. NUNES Paulo (20/03/2000) Contingent Valuation of the Benefits of Natural Areas and its Warmglow Component. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 2000. XXI + 282 pp.

134. VAN DEN CRUYCE Bart (7/04/2000) Statistische discriminatie van allochtonen op jobmarkten met rigide lonen. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische Wetenschappen, 2000. XXIII + 441 pp.

135. REPKINE Alexandre (15/03/2000)

Industrial restructuring in countries of Central and Eastern Europe: Combining

branch-, firm- and product-level data for a better understanding of Enterprises'

behaviour during transition towards market economy.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2000. VI + 147 pp.

99

136. AKSOY, Yunus (21/06/2000)

Essays on international price rigidities and exchange rates.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2000. IX + 236 pp.

137. RIYANTO, Yohanes Eko (22/06/2000)

Essays on the internal and external delegation of authority in firms.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2000. VIII + 280 pp.

138. HUYGHEBAERT, Nancy (20/12/2000)

The Capital Structure of Business Start-ups.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2000. VIII + 332 pp.

139. FRANCKX Laurent (22/01/2001)

Ambient Inspections and Commitment in Environmental Enforcement.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2001 VIII + 286 pp.

140. VANDILLE Guy (16/02/2001)

Essays on the Impact of Income Redistribution on Trade.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2001 VIII + 176 pp.

141. MARQUERING Wessel (27/04/2001)

Modeling and Forecasting Stock Market Returns and Volatility.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2001. V + 267 pp.

142. FAGGIO Giulia (07/05/2001)

Labor Market Adjustment and Enterprise Behavior in Transition.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2001. 150 pp.

143. GOOS Peter (30/05/2001)

The Optimal Design of Blocked and Split-plot experiments.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2001.X + 224 pp.

144. LABRO Eva (01/06/2001)

Total Cost of Ownership Supplier Selection based on Activity Based Costing and

Mathematical Programming.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2001. 217 pp.

145. VANHOUCKE Mario (07/06/2001)

Exact Algorithms for various Types of Project Scheduling Problems. Nonregular

Objectives and time/cost Trade-offs. 316

100

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2001. 316 pp.

146. BILSEN Valentijn (28/08/2001)

Entrepreneurship and Private Sector Development in Central European

Transition Countries.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2001. XVI + 188 pp.

147. NIJS Vincent (10/08/2001)

Essays on the dynamic Category-level Impact of Price promotions.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2001.

148. CHERCHYE Laurens (24/09/2001)

Topics in Non-parametric Production and Efficiency Analysis.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2001. VII + 169 pp.

149. VAN DENDER Kurt (15/10/2001)

Aspects of Congestion Pricing for Urban Transport.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2001. VII + 203 pp.

150. CAPEAU Bart (26/10/2001)

In defence of the excess demand approach to poor peasants' economic behaviour.

Theory and Empirics of non-recursive agricultural household modelling.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2001. XIII + 286 blz.

151. CALTHROP Edward (09/11/2001)

Essays in urban transport economics.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2001.

152. VANDER BAUWHEDE Heidi (03/12/2001)

Earnings management in an Non-Anglo-Saxon environment.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2001. 408 pp.

153. DE BACKER Koenraad (22/01/2002)

Multinational firms and industry dynamics in host countries : the case of

Belgium.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2002. VII + 165 pp.

154. BOUWEN Jan (08/02/2002)

Transactive memory in operational workgroups. Concept elaboration and case

study.

101

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2002. 319 pp. + appendix 102 pp.

155. VAN DEN BRANDE Inge (13/03/2002)

The psychological contract between employer and employee : a survey among

Flemish employees.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2002. VIII + 470 pp.

156. VEESTRAETEN Dirk (19/04/2002)

Asset Price Dynamics under Announced Policy Switching.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2002. 176 pp.

157. PEETERS Marc (16/05/2002)

One Dimensional Cutting and Packing : New Problems and Algorithms.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2002.

158. SKUDELNY Frauke (21/05/2002)

Essays on The Economic Consequences of the European Monetary Union.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2002.

159. DE WEERDT Joachim (07/06/2002)

Social Networks, Transfers and Insurance in Developing countries.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2002. VI + 129 pp.

160. TACK Lieven (25/06/2002)

Optimal Run Orders in Design of Experiments.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2002. XXXI + 344 pp.

161. POELMANS Stephan (10/07/2002)

Making Workflow Systems work. An investigation into the Importance of Task-

appropriation fit, End-user Support and other Technological Characteristics.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2002. 237 pp.

162. JANS Raf (26/09/2002)

Capacitated Lot Sizing Problems : New Applications, Formulations and

Algorithms.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2002.

163. VIAENE Stijn (25/10/2002)

Learning to Detect Fraud from enriched Insurance Claims Data (Context, Theory

and Applications).

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2002. 315 pp.

102

164. AYALEW Tekabe (08/11/2002)

Inequality and Capital Investment in a Subsistence Economy.Leuven,

K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2002. V + 148 pp.

165. MUES Christophe (12/11/2002)

On the Use of Decision Tables and Diagrams in Knowledge Modeling and

Verification.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2002. 222 pp.

166. BROCK Ellen (13/03/2003)

The Impact of International Trade on European Labour Markets.

K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen,

2002.

167. VERMEULEN Frederic (29/11/2002)

Essays on the collective Approach to Household Labour Supply.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2002. XIV + 203 pp.

168. CLUDTS Stephan (11/12/2002)

Combining participation in decision-making with financial participation :

theoretical and empirical perspectives.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2002. XIV + 247 pp.

169. WARZYNSKI Frederic (09/01/2003)

The dynamic effect of competition on price cost margins and innovation.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen

2003.

170. VERWIMP Philip (14/01/2003)

Development and genocide in Rwanda ; a political economy analysis of peasants

and power under the Habyarimana regime.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2003.

171. BIGANO Andrea (25/02/2003)

Environmental regulation of the electricity sector in a European Market

Framework.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2003. XX + 310 pp.

172. MAES Konstantijn (24/03/2003)

Modeling the Term Structure of Interest Rates Across Countries.

103

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2003. V+246 pp.

173. VINAIMONT Tom (26/02/2003)

The performance of One- versus Two-Factor Models of the Term Structure of

Interest Rates.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2003.

174. OOGHE Erwin (15/04/2003)

Essays in multi-dimensional social choice.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2003. VIII+108 pp.

175. FORRIER Anneleen (25/04/2003)

Temporary employment, employability and training.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2003.

176. CARDINAELS Eddy (28/04/2003)

The role of cost system accuracy in managerial decision making.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2003. 144 pp.

177. DE GOEIJ Peter (02/07/2003)

Modeling Time-Varying Volatility and Interest Rates.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2003. VII+225 pp.

178. LEUS Roel (19/09/2003)

The generation of stable project plans. Complexity and exact algorithms.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2003.

179.MARINHEIRO Carlos (23/09/2003)

EMU and fiscal stabilisation policy : the case of small countries.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen

2003.

180. BAESSENS Bart (24/09/2003)

Developing intelligent systems for credit scoring using machine learning

techniques.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2003.

181. KOCZY Laszlo (18/09/2003)

Solution concepts and outsider behaviour in coalition formation games.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2003.

104

182. ALTOMONTE Carlo (25/09/2003)

Essays on Foreign Direct Investment in transition countries : learning from the

evidence.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2003.

183. DRIES Liesbeth (10/11/2003)

Transition, Globalisation and Sectoral Restructuring: Theory and Evidence from

the Polish Agri-Food Sector. Leuven, K.U.Leuven, Faculteit Economische en

Toegepaste Economische Wetenschappen, 2003.

184. DEVOOGHT Kurt (18/11/2003)

Essays On Responsibility-Sensitive Egalitarianism and the Measurement of

Income Inequality. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste

Economische Wetenschappen, 2003.

185. DELEERSNYDER Barbara (28/11/2003)

Marketing in Turbulent Times. Leuven, K.U.Leuven, Faculteit Economische en

Toegepaste Economische Wetenschappen, 2003.

186. ALI Daniel (19/12/2003)

Essays on Household Consumption and Production Decisions under Uncertainty

in Rural Ethiopia.”. Leuven, K.U.Leuven, Faculteit Economische en Toegepaste

Economische Wetenschappen, 2003.

187. WILLEMS Bert (14/01/2004)

Electricity networks and generation market power.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2004.

188. JANSSENS Gust (30/01/2004)

Advanced Modelling of Conditional Volatility and Correlation in Financial

Markets.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2004.

189. THOEN Vincent (19/01/2004)

"On the valuation and disclosure practices implemented by venture capital

providers"

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2004.

190. MARTENS Jurgen (16/02/2004)

“A fuzzy set and stochastic system theoretic technique to validate simulation

models”.Leuven, K.U.Leuven, Faculteit Economische en Toegepaste

Economische Wetenschappen, 2004.

191. ALTAVILLA Carlo (21/05/2004)

“Monetary policy implementation and transmission mechanisms in the Euro

area.”,

105

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2004.

192. DE BRUYNE Karolien (07/06/2004)

“Essays in the location of economic activity”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2004.

193. ADEM Jan (25/06/2004)

“Mathematical programming approaches for the supervised classification

problem.”,

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2004.

194. LEROUGE Davy (08/07/2004)

“Predicting Product Preferences : the effect of internal and external cues.”,

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2004.

195. VANDENBROECK Katleen (16/07/2004)

“Essays on output growth, social learning and land allocation in agriculture :

micro-evidence from Ethiopia and Tanzania”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2004.

196. GRIMALDI Maria (03/09/004)

“The exchange rate, heterogeneity of agents and bounded rationality”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2004.

197. SMEDTS Kristien (26/10/2004)

“Financial integration in EMU in the framework of the no-arbitrage theory”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2004.

198. KOEVOETS Wim (12/11/2004)

“Essays on Unions, Wages and Employment”

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2004.

199. CALLENS Marc (22/11/2004)

“Essays on multilevel logistic Regression”

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2004.

200. RUGGOO Arvind (13/12/2004)

“Two stage designs robust to model uncertainty”

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2004.

106

201. HOORELBEKE Dirk (28/01/2005)

”Bootstrap and Pivoting Techniques for Testing Multiple Hypotheses.”

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2005.

202. ROUSSEAU Sandra (17/02/2005)

“Selecting Environmental Policy Instruments in the Presence of Incomplete

Compiance”,

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2005.

203. VAN DER MEULEN Sofie (17/02/2005)

“Quality of Financial Statements : Impact of the external auditor and applied

accounting standards”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2005.

204. DIMOVA Ralitza (21/02/2005)

“Winners and Losers during Structural Reform and Crisis : the Bulgarian Labour

Market Perspective”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2005.

205. DARKIEWICZ Grzegorz (28/02/2005)

“Value-at-risk in Insurance and Finance : the Comonotonicity Approach”

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2005.

206. DE MOOR Lieven (20/05/2005)

“The Structure of International Stock Returns : Size, Country and Sector Effects

in Capital Asset Pricing”

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2005.

207. EVERAERT Greetje (27/06/2005)

“Soft Budget Constraints and Trade Policies : The Role of Institutional and

External Constraints”

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2005.

208. SIMON Steven (06/07/2005)

“The Modeling and Valuation of complex Derivatives : the Impact of the Choice

of the term structure model”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2005.

209. MOONEN Linda (23/09/2005)

“Algorithms for some graph-theoretical optimization problems”.

107

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2005.

210. COUCKE Kristien (21/09/2005)

“Firm and industry adjustment under de-industrialisation and globalization of the

Belgian economy”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2005.

211. DECAMPS MARC (21/10/2005)

“Some actuarial and financial applications of generalized diffusion processes”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2005.

212. KIM HELENA (29/11/2005)

“Escalation games: an instrument to analyze conflicts. The strategic approach to

the bargaining problem”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2005.

213. GERMENJI ETLEVA (06/01/2006)

“Essays on the economics of emigration from Albania”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

214. BELIEN JEROEN (18/01/2006)

“Exact and heuristic methodologies for scheduling in hospitals: problems,

formulations and algorithms”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

215. JOOSSENS KRISTEL (10/02/2006)

“Robust discriminant analysis”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

216. VRANKEN LIESBET (13/02/2006)

“Land markets and production efficiency in transition economies”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

217. VANSTEENKISTE ISABEL (22/02/2006)

“Essays on non-linear modelling in international macroeconomics”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

218. WUYTS Gunther (31/03/2006)

“Essays on the liquidity of financial markets”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

108

219. DE BLANDER Rembert (28/04/2006)

“Essays on endogeneity and parameter heterogeneity in cross-section and panel

data”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

220. DE LOECKER Jan (12/05/2006)

“Industry dynamics and productivity”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

221. LEMMENS Aurélie (12/05/2006)

“Advanced classification and time-series methods in marketing”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

222. VERPOORTEN Marijke (22/05/2006)

“Conflict and survival: an analysis of shocks, coping strategies and economic

mobility in Rwanda, 1990-2002”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

223. BOSMANS Kristof (26/05/2006)

“Measuring economic inequality and inequality aversion”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

224. BRENKERS Randy (29/05/2006)

“Policy reform in a market with differentiated products: applications from the car

market”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

225. BRUYNEEL Sabrina (02/06/2006)

“Self-econtrol depletion: Mechanisms and its effects on consumer behavior”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

226. FAEMS Dries (09/06/2006)

“Collaboration for innovation: Processes of governance and learning”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

227. BRIERS Barbara (28/06/2006)

“Countering the scrooge in each of us: on the marketing of cooperative

behavior”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

109

228. ZANONI Patrizia (04/07/2006)

“Beyond demography: Essays on diversity in organizations”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

229. VAN DEN ABBEELE Alexandra (11/09/2006)

“Management control of interfirm relations: the role of information”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

230. DEWAELHEYNS Nico (18/09/2006)

“Essays on internal capital markets, bankruptcy and bankruptcy reform”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

231. RINALDI Laura (19/09/2006)

“Essays on card payments and household debt”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

232. DUTORDOIR Marie (22/09/2006)

“Determinants and stock price effects of Western European convertible debt

offerings: an empirical analysis”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

233. LYKOGIANNI Elissavet (20/09/2006)

“Essays on strategic decisions of multinational enterprises: R&D

decentralization, technology transfers and modes of foreign entry”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

234. ZOU Jianglei (03/10/2006)

“Inter-firm ties, plant networks, and multinational firms: essays on FDI and trade

by Japanse firms.”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.

235. GEYSKENS Kelly (12/10/2006)

“The ironic effects of food temptations on self-control performance”.

Leuven, K.U.Leuven, Faculteit Economische en Toegepaste Economische

Wetenschappen, 2006.