Emotional Stroop Task

INFANTS, INQUIRIES, AND PERCEPTUAL INCONSISTENCIES 1

Infants, Inquiries, and Perceptual Inconsistencies: An Emotional Stroop Task Analyzing

Stimuli Pairings of Congruent and Incongruent Visuals and Audio

Alex Dorman, Kelsey Schulman, Alex Stopka, Brittany Wilder

The College of Wooster


Abstract

A modified emotional Stroop test was presented to the participants in the form of

incongruent and congruent auditory and visual stimuli. Participants viewed happy babies paired

with crying audio, sad babies paired with laughing audio, happy babies paired with laughing

audio and sad babies paired with crying audio. They were asked to report the emotion shown in

the photo, and to ignore the audio. We hypothesized that the congruent image/audio paring

would elicit a faster response time and account for less error rate. Results indicated that

participants responded faster to congruent image/audio pairings and made fewer errors.


Infants, Inquiries, and Perceptual Inconsistencies: An Emotional Stroop Task Analyzing

Stimuli Pairings of Congruent and Incongruent Visuals and Audio

Attention is the mechanism by which we navigate our surroundings. Humans depend

upon their ability to attend to important stimuli in order to interpret information that will

correctly influence their actions (Fenske & Eastwood, 2003). Attention moderates many aspects

of functioning, such as development of skills, perceiving the world, immediate responses, and

memory recall (Parasuramen, 1998). But our ability to attend to the world around us is limited by

our cognitive capabilities (Parasuramen, 1998; Fenske & Eastwood, 2003; Buschman & Miller,

2010). Due to our limitations in perceiving our world, research in this field is crucial and has

been of interest dating back to the principals of psychology first published by William James in

1890 (MacLeod & Dunbar, 1988).

One common theory of how humans allocate attention is via one of two processes:

Automatic processing of information; Or controlled processing of information (Beall & Herbert,

2008; Macleod & Dunbar, 1988; Shiffrin & Schneider, 1977; Shiffrin & Shneider, 1984; Cohen,

Dunbar, McClelland, 1990). Automatic processing of information is often characterized as rapid

and unintentional, and uses little relative cognitive function. An example of automatic processing

would be reading a single presented word. This is automatic processing (for someone who is

literate) because the word is processed before it can be ignored (Beall & Herbert, 2008).

Controlled processing of information is somewhat the opposite, it is information that depends on

a “cognitive strategy, and requires cognitive resources” (Macleod & Dunbar, 1988). While these

two forms of processing seem to be inherently in opposition, a combination of the two processes


is used in all information processing (Shiffrin & Schneider, 1984), and can be manipulated, to an

extent, with training in learning how to automatically process (or ignore) stimuli not normally

automatically processed or ignored (MacLeod & Dunbar, 1988; Beall & Herbert, 2008; Cohen et

al., 1990). This would explain why reading is an automatic process for literate adults; they have

lots of practice processing words.

In an attempt to understand how humans utilize the finite amount of attention processing

capabilities they’ve been given, psychologists often turn to the Stroop Task. The Stroop Task,

created by John Ridley Stroop in 1935, was described as the “Gold Standard of Attentional

Measures” (Macleod, 1992). It allows researchers to test interferences among two stimuli, which

in turn reveals which process is more automatic between the two. Put in other words, if one

stimulus interferes with the processing of the other stimulus, it is because the interfering stimulus

is being processed more rapidly. In its original form, Stroop called it the “Naming Color Test”.

The focus was to identify the color of the word, ignoring what the word said. For example, the

word “red” could be printed in blue, and it was the participant’s job to identify the color blue.

(Stroop, 1935). What Stroop discovered was there was an apparent asymmetry between the

processing of these paired stimuli. The participants were only marginally hindered in identifying

the words themselves when they were printed in different colored ink, but response times in

identifying the color of the ink the words were printed in were significantly affected. Stroop

concluded that this meant that associations formed between words and their representations were

processed more automatically than color stimuli and their respective names (Stroop, 1935).

` Given the Stroop Task’s effectiveness in identifying interference effects, it has been used

hundreds of times in the testing of human attention (Macleod, 1992). It can be utilized across


many different fields using slight variations to the test design. In the field of clinical psychology,

one study changed the words being reported to have significant relevance to different

psychopathologies, and clients reporting on the colors of words had a harder time doing so when

the words were representative of an aspect of a psychopathology similar to said participant’s

clinical condition, opening the door to research focusing on attentional bias in clients with

psychopathologies (Williams, Mathews, MacLeod 1996). The Stroop Task has also been

reviewed as a valuable tool in identifying implicit attitudes in sexual offenders (Price, Beech,

Mitchell, Humphreys, 2012). Among other things, the Stroop task has also been used as a way of

identifying aspects of embodied cognition (Paelecke, Paelecke-Habermann, Borkenau, 2012).

This is just a small sample of the diverse applications of the Stroop Task.

One common variation of the Stroop task utilizes faces as one of the two stimuli

presented (Beall & Herbert, 2008; Ovaysikia, Tahir, Chan, DeSouza, 2011; Avram, Baltes,

Miclea, Miu 2010). Faces are of particular interest because countless research has shown that

human’s process faces differently than non-facial objects (Rakover, 2013; Reed, Stone, Bozova,

Tanaka, 2003; Murray, Yong, Rhodes, 2000). There is much interest in where our attention is

allocated when it comes to processing faces paired with other stimuli, and why it is our attention

allocation behaves in the ways it does. In the current study, researchers developed a variation of

the Emotional Stroop Task, utilizing pairings of faces and vocalizations.

Research in the area of multisensory perception when it comes to recognizing the

expression of emotion is relatively scarce (Collignon et al., 2008). Previous research suggests

that congruent affect of visual and audio stimuli leads to faster processing of information, while

incongruent affect of visual and audio stimuli leads to slower processing of information


(Collignon et al., 2008; Dolan, Morris, Gelder, 2000; Massaro & Egan, 1996). Collignon et al.

(2008) reported that between audio and visual stimuli, the visual stimulus (the face) was

processed more automatically than audio stimulus, resulting in quicker identification of facial

expression even when the paired audio stimulus was incongruent in affect. However Collignon et

al. (2008) stressed that visual dominance in affect perception was not rigid, but instead very

flexible and situation-dependent. This is in partial agreement with Massaro & Egan (1996) who

stressed that both visual and audio stimulus cues were equally utilized in identifying affect of

stimuli.

Yet what is it that dictates our attention allocation to certain stimuli? There is current

research to support the theory that while both valence of the stimuli and arousal of the observer

upon observing said stimuli manipulate processing, it is the strength of arousal that is more

influential. Put in other words, it is the intensity of emotional response to certain stimuli, as

opposed to the stimuli’s inherent positive or negative affect, that affects our processing (Dresler

& Meriau, 2008).

The current study aims to expand off of previous research by making use of stimuli that

are very potent in eliciting emotional response. We will be utilizing black and white images of

thirty different babies, paired with ten different four second audio samples of babies. Half of the

thirty images of babies will be conveying clear positive emotions, while the other half will be

conveying clear sad emotions. Five of the audio samples will contain babies conveying positive

emotions (laughing), while the other five will convey negative emotions (crying). Faces are

established as being processed automatically (Rakover, 2013; Reed et al., 2003; Murray et al.,

2000), and are commonly used in the Emotional Stroop Task (Beall & Herbert, 2008; Ovaysikia


et al., 2011, Avram et al., 2010). However, no researcher has utilized infant vocalizations as far

as the researchers are aware. Reasons for the decision to use infant vocalizations stem from the

importance of infant vocalizations on human attention, in particular the effect of infantile crying

on human arousal responses (Parsons, Young, Parsons, Stein, Kringelbach, 2011; Boukydis &

Burgees, 1982; Zeskind & Collins, 1987). Such effects include the activation of the autonomic

nervous system (Parsons et al., 2011) and the urgency to soothe the infant (Boukydis & Burgees,

1982). While there is little to no research on the response of infantile laughter on human arousal,

research on laughing itself shows such physiological responses like changes in heart rate, skin

temperature, and brain activity, which may be linked with overall improved well being (Bennet,

Zeller, Rosenberg, McCann, 2003). So it seems feasible that observers would also elicit as strong

an arousal to infantile laughter as they would to infantile crying. This is particularly feasible

because these audio stimuli (infantile laughing and crying) will inherently be emotionally

arousing and of clear positive/negative valence, the discrepancy between what specifically

moderates the Stroop Effect, arousal or valence, will not be of issue to our research.

The current study will expose participants to one of four situations in rapid succession: A

visual of a baby with positive valence (smiling) and audio of a baby with negative valence

(laughing); A visual of a baby with positive valence and audio of a baby with negative valence

(crying); A visual of a baby with negative valence (frowning) and audio of a baby with positive

valence; A visual of a baby with negative valence and audio of a baby with negative valence.

Two of these scenarios are congruent pairings, and the other two are incongruent pairings. The

participant will be asked to identify the valence of the images in our first experiment, and the

valence of the audio in the second experiment, their response time in doing so will be further

analyzed.


The current hypothesis is that a Stroop effect will occur, meaning stimuli that are

incongruent with one another when paired together will result in extended latency periods. The

second hypothesis is that that there will be a Stroop asymmetry effect between visual and audio

stimuli, which will expose an attentional bias towards processing infant vocalizations more

rapidly. This is hypothesized in light of Massaro and Egan’s (1996) conclusion that humans

utilize auditory and visual information in an optimal manner for perception, in accordance with

the idea presented by Collignon et al. (2008) of perception being flexible and situation

dependent, and keeping in mind the research stating that infant vocalizations can be of intrinsic

importance to humans (Parsons et al., 2011; Boukydis & Burgees, 1982; Zeskind & Collins,

1987). Finally, the hypothesis falls in line with Beall and Herbert’s (2008) findings that “while

all information can be processed automatically, not all information is of equal importance”.

Method

Participants

The participants consisted of 30 College of Wooster undergraduate students, ages 18-22.

There were 15 students (females=6, males= 9) who completed experiment one and 15 students

(females= 5, males=10) who completed experiment two. Students were recruited through an

online subject pool for another study and volunteered to additionally participate in the current

study. Participants had normal hearing.

Materials

Baby Photos and Audio. To measure the emotional stroop effect, baby photos and baby audio

clips were used. To test the congruency of the emotional content of audio and visual stimuli, ten

happy baby photos, ten sad baby photos, ten happy baby audio clips and ten sad baby audio clips

were presented to participants. The baby photos were randomly paired with the audio clips and


presented to participants in two experiments. The baby photos were in color and 500 x 500

pixels. The audio clips were four seconds long (see Appendix A).

Direct RT. The participants were presented with the stimuli using the Direct RT program. There

were 40 possible combinations of baby images and audio. Each participant randomly viewed 20

pairs of baby images and audio per experiment. There were ten happy photos randomly paired

with sad audio clips and ten sad photos paired with happy audio clips that made up the

incongruent stimuli; ten happy photos paired with happy audio and ten sad photos paired with

sad audio made up the congruent stimuli. The audio played for two seconds before the image

appeared on the screen, and there were two seconds where the participant simultaneously viewed

the image and heard the audio. Direct RT recorded the reaction time of each participant.

Procedure

In the first experiment participants who volunteered for the experiment met in the

designated room and signed the consent form. After signing the form, the participant was

instructed to follow the experimenter into the audio room and asked to take a seat at the chair in

front of the computer. The experimenter explained that the participant would place the

headphones on and view a series of photos and hear an audio clip. Each participant was asked to

ignore the voice and respond to the image as quickly and accurately as possible and say if the

photo was happy or sad; using their dominant index finger participants pressed the left arrow key

for happy or the right arrow key for sad. Once the participant completed the experiment a black

screen appeared indicting the experiment was over. In the second experiment the procedure was

the same except the participant was now told to ignore the face and indicate if the voice was

happy or sad using the same arrow keys. Once the participant completed the experiment they


received a debriefing form explaining the experiment and thanking the participant for

volunteering to do the experiment.


Appendix A: Example Baby Photos

Audio clips available upon request

Results


The present study expanded off of previous research by making use of stimuli that are

very potent in eliciting emotional response. The researchers hypothesized that a Stroop effect

would occur, meaning stimuli that are incongruent with one another when paired together will

result in extended latency periods. The researchers also hypothesized that there would be a

Stroop asymmetry effect between visual and audio stimuli, which will expose an attentional bias

towards processing infant vocalizations more rapidly. The first experiment had the participants

ignore the happy or sad voice and determine if the baby face was happy or sad. A paired samples

t-test was conducted to test for differences between congruent and incongruent conditions in

Experiment 1. The congruent group had a mean of 1021.19 (SD = 510.27) and the incongruent

group had a mean of 1005.14 (SD = 457.69). There was no significant difference between the

congruent and incongruent groups t (12) =.61, p > .05. The second experiment had the

participants ignore the baby face and determine if the baby voice was happy or sad. A paired

sample t-test was conducted. The congruent group had a mean of 1523.53 (SD = 501.12) and the

incongruent group had a mean of 1589.22 (SD = 573.71). There was also no significant

difference between the congruent and incongruent groups in this experiment t (12) = .13, p > .05.

Discussion

The overall findings of the current study suggest that there is no difference in processing

information when stimuli are congruent or incongruent, specifically for infant faces and laughing

and crying audio. While previous research has been effective in using the Stroop Task in various

studies, the Stroop Task in this study proved to be ineffective. There was no Stroop effect found

for either experiment 1 or experiment 2.


In experiment one; there was no difference between the processing of incongruent stimuli

and congruent stimuli, where audio precluded the photo. This suggests that there were was no

difference in difficulty in indicating the emotion in, for example, a happy photo when there is a

baby cry simultaneously playing and when there is a laugh simultaneously playing. Previous

research demonstrated that there are discrepancies in how two stimuli are processed, where one

may be processed faster (more automatically) than the other, and the stroop test examines

interferences among two stimuli, which in turn reveals which process is more automatic between

the two (Macleod, 1992, Stroop, 1935). The audio appearing before the photo did not change the

processing of the photo, which is supported by the finding that visual dominance in affect

perception was not rigid, but instead very flexible and situation-dependent (Collignon et al.

2008).

The emotional stroop test we implemented showed that neither the infant vocalizations

nor the baby photo is processed more automatically than the other. Parasuramen (1998) states the

importance of attention in navigating one’s surroundings and in mediating immediate responses.

There is also evidence that suggests that human’s process faces differently than non-facial

objects (Rakover, 2013; Reed, Stone, Bozova, Tanaka, 2003; Murray, Yong, Rhodes, 2000).

Considering our findings, there may be something different about infant photos and vocalizations

that are easier to identify even when there is incongruent audio and visual information. The

emotional valence and intensity of both laughter and crying seemed to create no differences in

how the participant responded to the photo. Overall, the participant’s attention was not thwarted

by the incongruent audio presented with the photo, which is an interesting finding considering

past successes of the stroop test. This also highlights the way our experience with human faces

and emotions differs from everyday object perception.


The second experiment tested the Stroop effect of audio recordings while having

participants ignore a picture. Our hypothesis was not supported and there was no significant

difference found between the congruent and incongruent groups. These results are intriguing

because literature states that humans allocate attention via automatic processing, or controlled

processing (Beall & Herbert, 2008). If information had been processed via automatic processing,

then the expected result would be that of inconsistency between incongruent and congruent

stimuli. Instead, we found consistencies even between congruent and incongruent stimuli.

Literature also discusses how all information processing could be manipulated with training on

how to automatically process or ignore stimuli that was not normally processed or ignored

(Macleod & Dunbar, 1988). Humans are naturally inclined to devote major attention to human

faces as well as voices. Results may have differed had the participants been trained to ignore the

faces. Evolutionarily, humans are attuned to baby faces and vocalizations; because infants are

defenseless and these emotional cues are pertinent in identifying if a baby is in need. Previous

research has also suggested that congruent affect of visual and audio stimuli leads to faster

processing of information, while incongruent affect of visual and audio stimuli leads to slower

processing of information (Collignon et al., 2008; Dolan, Morris, Gelder, 2000; Massaro &

Egan, 1996). However, neither of our experiments supported this previous finding and further

research would be beneficial for investigating why no effect was found.

There are various factors that may have influenced the results. The limited sample of 30

participants, most of which were psychology students at the College of Wooster, may have

contributed to the insignificant findings. Testing a broader, larger sample may have increased the

statistical power of the results. It may have been interesting to analyze the participant’s exposure

to infants as this may influence the results. Future research should take into account these


variables. This study is beneficial to research in this field because this is one of the few studies

conducted on incongruent and congruent emotional valence. This is a good base for examining

the way we interact with our environment and how we process dual modalities and multisensory

perception.

Some key strategies to move this literature forward include (a) larger sample sizes, (b) a

more controlled environment with more detailed instructions, and (c) more elaborate background

information on the participants. While we used a sample of 30 participants; a sample size capable

of producing statistical significance, testing a larger sample may have allowed our results to

support our hypotheses. Prior to the study, we instructed participants of how to complete the

experiment as well as providing them with instructions on the computer screen in which they

used. However, we left out the minor detail of making sure they clicked the arrows as fast as they

could. We also could have been more specific, informing the participants to leave their eyes open

while they were ignoring the visual stimuli, and to keep the head phones on while ignoring the

audio stimuli. While this minor detail most likely was not the resulting factor of our insignificant

results, it may have influenced the outcome. One last key strategy that could help to move this

literature forward is that of having more information on our participants. Participants with

previous exposure to infants may have had an advantage when completing our study, while

participants with less exposure to infants may have been at a disadvantage. Avenues in which

this study could take could possibly be that of sex differences in analyzing incongruent and

congruent identification, research dealing with infant vocalizations. Psychological fields that

could benefit greatly by research in this area include developmental psych, social psych as well

as behavioral and neuro psych.



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Emotional Stroop Task