Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Chapter 10

Motivation

Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Motivation

• Motivation– Motivation is a condition that energizes behavior and

gives it direction– Arises from two sources – from internal drive factors

(e.g. hunger) & external incentive factors (e.g. food)– Incentives

• Primary reinforcers – able to act as rewards independently of prior experience

• Secondary reinforcers – able to act as rewards at least partly through learning about their relationship to other events

Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Drives & Homeostasis

• Drive factors are generally directed towards maintaining homeostasis

• Homeostasis involves:– Set point – value homeostatic system tries to maintain– Sensory signal that measures internal state– Comparison between set point & sensory signal– Response that reduces difference between the two

Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Drives & Homeostasis

• Body temperature & homeostasis– Control processes to maintain temperature include

physiological responses (e.g. sweating & shivering), and psychological responses (e.g. find shade, remove clothing, cool drink)

– Neurons in various parts of the brain (especially the hypothalamus) detect temperature changes & trigger physiological responses & sensations that lead to behavioral solutions

Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Drives & Homeostasis

• Thirst as a homeostatic process– Two kinds of fluid reservoirs in the body – intracellular

reservoir & extracellular reservoir– Loss of extracellular fluid detected by blood-pressure

sensors, neurons in major veins & organs that respond to drop in pressure = thirst

– Loss of intracellular fluid detected by osmotic sensors, neurons in the hypothalamus that respond to dehydration = thirst

Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Incentive Motivation & Reward

• Incentive motivation– Wanting something associated with affect (full range

of consciously experienced pleasure & displeasure)– Most incentives need to be learned – incentive

salience (objects/events been linked to anticipated pleasurable affect)

– Wanting – anticipation of pleasure whereas liking – pleasure experienced in the moment

– Dopamine system in the brain appears to underlie experience of “wanting”

Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Hunger, Eating, & Eating Disorders

• Hunger– More complex than thirst – as we need to eat a balance of foods

to be healthy– We have both basic taste preferences that we are born with &

mechanisms for learning preferences & aversions

• Interactions between homeostasis & incentives– Homeostasis is the dominant operating principle in control of

hunger but incentive factors are important too• Oral stimulation & learning are both important parts of the

interaction between physiological hunger signals & incentive stimuli of eating

Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Hunger, Eating, & Eating Disorders

• Physiological hunger cues– Related to glucose levels & other nutrients in the body– Neurons in the brain (especially brain stem &

hypothalamus) sensitive to glucose levels– Peripheral signals – nutrient signals in the liver,

stomach & intestines trigger satiety to the brain

• Integration of hunger cues– Signals from hunger receptors in the brain & satiety

signals from liver & stomach integrated in brain stem to detect overall need

Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Hunger, Eating, & Eating Disorders

• ...Integration of hunger cues– Hypothalamus - two key areas related to hunger

• Lateral hypothalamus – destruction leads to undereating• Ventromedial hypothalamus – destruction leads to

overeating

– The idea that the two parts of the hypothalamus “hunger centre” too simplistic

• Research on lesions in the lateral and ventromedial hypothalamus suggests this more complex

Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Hunger, Eating, & Eating Disorders

Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Hunger, Eating, & Eating Disorders

Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Hunger, Eating, & Eating Disorders

• Obesity– Definition – 30% or more above ideal body weight. – People become obese mainly due to genetic

predisposition or they overeat (psychological reasons)– Genetic factors – obesity more likely in families where

one or more parents obese– Twin studies – research suggests identical twins gain

weight in same way– Research suggests that genes affect number & size

of fat cells, metabolic rate & set points

Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Hunger, Eating, & Eating Disorders

• ...Obesity– Overeating – psychological factors include breakdown

of conscious restraints (e.g. end of diet) & emotional arousal (e.g. when tense or anxious)

– Dieting & weight control• Limitations of dieting – extreme diets not successful because

deprivation leads to binge eating & decreases metabolic rate• Weight control programs – to succeed people need to

establish new set of permanent eating habits & exercise

Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Hunger, Eating, & Eating Disorders

Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Hunger, Eating, & Eating Disorders

• Anorexia & bulimia– Both these disorders involve pathological desire not to

gain weight & mostly affect women– Anorexia nervosa – characterized by extreme, self-

imposed weight loss– Bulimia – characterized by recurrent binge eating

followed by purging excess through vomiting/laxatives– Variety of causes for these disorders, including social,

biological or family factors with some combination of these probably necessary

Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Hunger, Eating, & Eating Disorders

• ...Anorexia & bulimia– Socio-cultural causes

• Emphasis on thinness in women in Western culture• Objectification theory – claims that self-objectification

(concerned more with how others see us than how we feel) causes range of psychological & emotional reactions – self-consciousness, increased anxiety & shame, & diminished positive emotions & sexual pleasure

Use with Atkinson & Hilgard’s Introduction to Psychology 15th editionNolen-Hoeksema, Fredrickson, Loftus, Wagenaar ISBN 9781844807284 © 2009 Cengage Learning

Hunger, Eating, & Eating Disorders

• ...Anorexia & bulimia– Biological causes

• Biological vulnerabilities may increase tendency to develop eating disorder, e.g. malfunction of hypothalamus (anorexia) or deficiency in neurotransmitter serotonin or executive functioning (bulimia)

– Familial causes• Many young women with eating disorders come from families

that demand “perfection” & extreme self-control but do not allow expressions of warmth & conflict