ASSESSMENT OF HOT AND COOL EXECUTIVE FUNCTIONING FOLLOWING

TRAUMA USING THE TRADITIONAL STROOP TASK, EMOTIONAL

STROOP TASK, AND A NOVEL IMPLICIT ASSOCIATION TEST

Erin Sullivan, M.S.

Thesis Prepared for the Degree of Master of Science

Department of Psychology

UNIVERSITY OF NORTH TEXAS

December 2015

APPROVED: Craig Neumann, Major Professor Adriel Boals, Committee Member

Jennifer Callahan, Committee Member

Sullivan, Erin. Assessment of Hot and Cool Executive Functioning following Trauma

using the Traditional Stroop Task, Emotional Stroop Task, and a Novel Implicit Association

Test. Master of Science (Psychology), December 2015, 61 pp.,11 tables, 4 illustrations,

references, 74 titles.

Individuals who have experienced a traumatic event and develop Post-Traumatic Stress

Disorder (PTSD) frequently show deficits in both primarily “cool” and “hot” cognitive executive

functions (e.g., traditional & emotional Stroop tasks, respectively) that can be impacted by high

affective salience. Given the dimensional nature of psychopathology, questions remain about

individuals within the general population who have experienced trauma but do not meet full

criteria for PTSD and yet may manifest problems in these areas, especially areas of hot and cool

executive functioning (EF). Thus, the current project was designed to assess hot and cool EF in a

relatively large sample of individuals from the general population who have experienced trauma

and currently demonstrate sub-clinical levels of post-traumatic symptoms. The Stroop task,

Emotional Stroop task, and a novel modified Implicit Association Test were utilized to assess EF

across a spectrum of individuals with varying traumatic histories and level of post-traumatic

symptoms. Results suggest that a greater frequency of trauma experiences was moderately

associated with worse performance on both hot and cool executive functioning measures.

Specifically, females within the sample evidenced a close relationship between traumatic

experiences, post-trauma symptoms, and executive functioning. Clinical and theoretical

implications are discussed.

ii

Copyright 2015

by

Erin Sullivan

TABLE OF CONTENTS

Title Page………………………………………………………………………………..i

Copyright Notice………………………………………………………………………..ii

Chapters

1. INTRODUCTION…………………………………………………………………...1

Affect and Executive Functioning: “Hot” and “Cool” Functions…...…2

Hot and Cool Executive Functioning Following Trauma………….…..6

Implicit Association Tests for Cognitive Research…………………....12

The Current Study……………………………………………………..15

2. METHOD……………………………………………………………………….…..17

3. RESULTS…………………………………………………………………….……..26

4. DISCUSSION…………………………………………………………………….…34

Tables and Figures………………………………………………………………….….41

References…………………………………………………………………………...…51

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1

INTRODUCTION

The impact of traumatic experiences on subsequent psychological functioning can be

significantly distressing and affect a wide range of affective, neurocognitive, and social

processes. Specifically, trauma experiences have been demonstrated to impact frontal lobe

functioning, particularly higher order cognitive processes like attention and executive functions,

which then may contribute to poor emotion regulation and other unsuccessful coping strategies

(Aupperle, Melrose, Stein, & Paulus, 2011). The documentable effects of trauma on neural

circuitry and real-world functioning are most often studied in individuals who have been

diagnosed with Posttraumatic Stress Disorder (PTSD), as this population represents the most

severely affected. Within the population of PTSD victims, much research has been conducted

with veterans who suffer traumatic experiences during military deployments. In 2012 the

Department of Defense reported that more than 2,300 projects were being carried out using

veterans with PTSD, funded by over 1.9 billion dollars (Office of Public and Intergovernmental

Affairs, 2012). Though less prevalent, substantial research is also being conducted in civilian

samples with PTSD. Research in this area generally focuses on individuals who meet criteria for

PTSD and are undergoing psychological treatment following abuse, assault, and other violence

(Cisler et al, 2015; Jayawickreme et al, 2013; Ullman, Relyea, Peter-Hagene, & Vasquez, 2013;

Pagotto et al, 2015).

Research on PTSD in both veteran and civilian populations is enhancing understanding

about difficulties these individuals face in emotional regulation, executive processing, and

affective/executive functioning integration. For example, evidence from recent studies suggests

that those who have experienced trauma selectively attend to negative, and specifically trauma-

related, emotional information (Caparos & Blanchette, 2014; Cisler et al, 2011). This attention

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pattern may contribute to the perpetuation of emotions associated with trauma and prolong

symptoms of anxiety and depression. However, less is known about how these deficits compare

in individuals in the general population who have experienced a traumatic event, but do not meet

full criteria for PTSD. Nevertheless, it is reasonable to hold that trauma victims with sub-clinical

symptoms may also experience disturbances, if not outright deficits, in “cool,” purely cognitive

executive functions, and “hot” executive functions that require integration of affective and

cognitive processing. Though hot and cool executive functioning deficits in sub-clinical trauma

victims are likely less severe than those found in PTSD patients, they may still have significant

impact on these individuals’ daily functioning. The current study was conducted to utilize

traditional cognitive and affective neuropsychological tests, along with a novel implicit

association test, to provide a better understanding of executive functioning in trauma-impacted

individuals within the general population.

Affect and Executive Functioning: “Hot” and “Cool” Functions

Executive functions are broadly conceptualized as mental processes underlying problem solving,

planning, mental flexibility, divided attention, and inhibition. This expanse of executive

functions is integral to higher order cognitive processing and resulting task completion in daily

activities. Because of their centrality to task performance in a variety of settings, executive

functions have been described as “those capacities that enable a person to engage successfully in

independent, purposive, self-serving behavior” (Lezak, 1995). Common activities of daily living

such as driving, planning and cooking a meal, completing schoolwork, and shopping involve the

interplay of multiple executive functions to perform (e.g., Farias et al., 2003). Impairments in

one or more executive functioning capabilities can have significant impact on one’s ability to

perform daily tasks adequately (Jefferson, Paul, Ozonoff, & Cohen, 2006).

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While executive functions were traditionally thought of as purely cognitive processes, the

role of affect in executive processing has become evident with more modern research. While

“cool” executive functions operate independent of affect, “hot” executive functions (Zelazo &

Miller, 2002) require regulation of affective and motivational responses integrated with cognitive

processes. These cool and hot functions primarily recruit separate areas of the prefrontal cortex

(PFC), with cool executive functioning largely involving the dorsolateral prefrontal cortex and

hot functioning eliciting the ventromedial and orbitofrontal cortex (Iordan, Dolcos, & Dolcos,

2013).

In real-world situations, stimuli or problems that hold more affective significance recruit

neural systems underlying hot executive processes. For example, developing a plan of action

when confronted with rapids on a kayaking course would recruit the frontal subcortical circuit

comprised of the ventral, medial, or orbitofrontal cortex with projections to the thalamus and

amygdala (Chan, Shum, Toulopoulou, & Chen, 2008). Emotional processing would integrate

with the executive function of planning to develop a response to the high-affect inducing

situation. A process with more neutral affective salience, such as planning a route while walking

down an empty sidewalk, would be considered a cool executive function. This purely cool

cognitive problem solving would be more likely to recruit the dorsolateral prefrontal cortex, and

rely less on amygdala or basal ganglia projections (Stuss, Shallice, Alexander, & Picton, 1995).

In neuropsychological assessment, executive functioning measures consisting of stimuli

with neutral emotional salience are typically used. The traditional Stroop task is one such

commonly used measure of purely cool executive functions. Originally developed in 1935, the

Stroop task has historically been considered a gold standard in assessment of executive

functioning due to its ability to assess automatic processing and cognitive inhibition. The Stroop

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task consists of color naming, word reading, and an incongruent color-word reading test. While

color naming and word reading tasks involve mostly automatic processing, the incongruent

color-word reading test requires the examinee to inhibit a pre-potent response to read the words

and instead name the color of the ink in which the words are printed.

Accuracy and response times across the three sections of the Stroop are the primary

diagnostic measures. While significantly slowed or inaccurate responses on the two more

automatic sections of the Stroop are meaningful in forming diagnostic impressions, most

individuals are able to adequately perform on these sections. The “Stroop Interference Effect”

describes the slowed response time observed in the incongruent color-word condition, and this

effect typically reveals the most important information about an individual’s inhibition and

attentional processing abilities (Uttl & Graff, 1997).

As the importance of affective activation and regulation in executive functioning is

becoming a more widely studied concept in neuropsychology, novel assessments of hot

executive functioning have been and continue to be developed. The modified Stroop task, also

called the Emotional Stroop task, combines psychometric properties central to the traditional

Stroop task with emotionally salient stimuli to examine affective regulation and its relationship

with inhibition and attentional processing (Watts, McKenna, Sharrock, & Trezise, 1986). While

color words comprising the traditional Stroop task have neutral emotional salience, word stimuli

on the Emotional Stroop task are emotionally charged in order to elicit an affective response.

The primary measures of the Emotional Stroop task are response time and accuracy in

naming the ink color in which emotionally charged words are written. As with the traditional

Stroop task where poorer performance reflects impaired inhibition of neutral words, slower

response times and lower accuracy scores on the Emotional Stroop task suggest attentional bias

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toward the emotional word, and poor inhibition to override this bias. Results from Stroop and

Emotional Stroop tasks suggest words containing any emotional salience cause more interference

than neutral words (McKenna & Sharma, 2004). In clinical samples, level of negative salience of

the emotion-related word and how the particular word relates to the assessed patient’s schemata

significantly affect this interference (Williams, Matthews, & MacLeod, 1996).

The traditional Stroop task can provide important diagnostic information pertinent to cool

executive functioning and the Emotional Stroop task may demonstrate how well affect and

executive functions are meaningfully integrated in hot cognitive processing. Yet, while the

names of these two assessments imply similar mechanisms underlying the two tasks, the hot

nature of the interference in the Emotional Stroop task appears to be more complex than the cool

executive functioning underlying the traditional Stroop task. In a traditional Stroop task an

individual is faced with incongruent color and word information, but there is no particular

incongruence between emotionally charged words and ink color information (Algom, Chajut, &

Lev, 2004). Therefore, while both tasks require the participant to intentionally inhibit intrusions,

the mechanism behind this inhibition is different depending on the nature of the word.

In the Emotional Stroop task, interference appears to be produced by a two-fold

mechanism of fast and slow components (McKenna & Sharma, 2004). The fast interference

component is elicited within a single trial, where an individual must inhibit their response to an

emotional word in order to respond to the color. A slow component consists of a carry-over

effect of emotional activation, and appears to span trials. Both the fast interference and slow

interference effects within the Emotional Stroop may provide useful information for

interpretation. The fast effect may reveal how an individual automatically responds to emotional

activation, and be more pronounced in clinical populations with high reactivity to certain words.

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The slow effect may be more relevant to interpretation in a wide range of clinical

disorders, as it demonstrates how efficiently the participant is able to disengage and down-

regulate emotion following initial activation (Phaf & Kan, 2007). Comparisons between response

times to blocks of words presented early and later in the Emotional Stroop task may reveal

differences between fast and slow effects of the task, with persisting slow response times

throughout the task suggesting a greater difficulty with down-regulation of emotion. Both the

fast effect of high reactivity and this broader difficulty with disengagement from affective

stimuli in the task may be especially prevalent in those who have experienced trauma and are

struggling to down-regulate attention to negative, trauma-related stimuli. Therefore, a study of

individual stimulus performance and a broader examination of response time throughout the task

are imperative within an examination of trauma impact in the general population, such as the

present study.

Hot and Cool Executive Functioning Following Trauma

It is estimated that 50 to 60 percent of people experience a significant traumatic event in their

lifetime (Aupperle, Melrose, Stein, & Paulus, 2011). The lifetime prevalence of PTSD is

approximately 7 percent for those in the general population, which is nearly two times higher for

veterans and other high-risk groups (Otis, McGlinchey, Vasterling, & Kerns, 2011). Additionally,

5 to 10 percent of the population will experience sub-threshold symptoms following a traumatic

event (Marshall et al, 2001). Effects of this traumatic event can be widespread and impact social

relationships, psychological adjustment, and/or cognitive functioning. Interpersonal social and

romantic relationships may be affected by lasting effects of the trauma, including social anxiety

and difficulties with trust, guilt, anger, and impulsive behavior (Frueh, Turner, Beidel, & Cahill,

2001). People who have experienced traumatic events may also be at an increased risk of mood

7

disorders like depression (O’Donnell, Creamer, & Pattison, 2004) and substance use disorders

(Back et al, 2000).

Biological effects of trauma within the brain include changes in catecholamine levels and

differential activation of various brain regions. Catecholamine research suggests low levels of

GABA (Vaiva et al, 2006) and increased norepinephrine (Geracioti et al, 2001) may contribute to

hyperarousal following trauma. Additionally, areas in the amygdala, prefrontal cortex, and

limbic system may demonstrate a change in functioning resulting in deficits in memory,

processing speed, emotional responses, and higher order functioning (Insel, 2010). With regard

to executive functioning, the experience of a traumatic event can affect how neural circuitry,

such as cortical and subcortical circuits underlying executive functioning, contribute to

processing of meaningful stimuli. Most research on executive functioning following trauma has

been performed on samples with post-traumatic stress disorder. This research reveals individuals

who have experienced trauma and continue to exhibit high post-traumatic symptoms may show

mild deficits in purely cognitive, cool executive functions (Leskin & White, 2007), and have

more pronounced impairment in regulating affect while performing hot executive functions

(Buckley, 2000).

Functional imaging (e.g., fMRI) assessments of individuals diagnosed with PTSD

performing cool executive functioning tasks reveals processing deficits in a number of prefrontal

brain regions. On inhibition tasks, individuals with persisting post-trauma symptoms tend to

demonstrate reduced activation of the inferior frontal, ventral, and dorsal lateral PFC (Falconer et

al, 2008). Updating tasks requiring working memory capacity when presented emotionally-

neutral information show similar patterns of decreased activation in several prefrontal cortex

areas, including the dorsal lateral prefrontal cortex, anterior cingulate cortex, and inferior frontal

8

cortex (Moores et al, 2008). It is worth nothing, though, that in each of these tasks trauma-neutral

information was presented. Negative valence trauma information may provide a more relevant

source of study for executive functioning tasks within this population, since it would have a more

direct link to functioning in daily life.

In an assessment setting, deficits in cool executive functioning present as impaired

performance on a range of standard neuropsychological tests. Individuals experiencing post-

traumatic symptoms have shown impairment on the Trail-Making Test and Verbal Fluency-

Switching task (Bechkam et al, 1998) suggesting difficulty with timed attentional shifting. These

results continued to hold after comorbid diagnoses, medication, and compensation seeking were

accounted for, suggesting validity and generalizability of performance. Impairment on the Go-no

Go, Stop Signal, and Attention Network Task (Shucard et al, 2008) is linked to decreased

activation in areas of the prefrontal cortex leading to poor behavioral inhibition. Research based

on the Stroop task has also revealed differences between individuals with high post-trauma

symptoms and those who have not experienced significant trauma in terms of reduced PFC

activation during attentional control and inhibition tasks (Stein, Kennedy, & Twamley, 2002;

Aupperle). Results from these tasks suggest that in daily life, trauma victims may have

impairment in cool executive functioning that presents as difficulty performing tasks requiring

planning, inhibition, and attentional control in the presence of neutral affective stimuli or

problems. Though they may range in severity, particularly for individuals who have experienced

trauma but do not meet criteria for PTSD, these difficulties could have an impact on everyday

activities such as planning to run errands, directing attention while driving, and inhibiting

impulses to over-spend while shopping.

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While there is evidence to support the notion that individuals with high levels of post-

traumatic symptoms may be at risk for problems in cool executive functioning, difficulties with

hot executive functioning in the presence of high affective salient stimuli appear to be much

more prevalent in this population. Functional imaging results suggest elevated post-traumatic

symptoms are associated with hyperactivity of the amygdala and insular cortex, which leads to

enhanced priming for threat cues (Hayes, VanElzakker, & Shin, 2012). Areas of the anterior

cingulate cortex (ACC) may be differentially activated and impaired in trauma victims, with less

activation of the rostral ACC and greater activation in the dorsal ACC when faced with

inhibition tasks that include negative stimuli (Shin et al, 2001).

Within the prefrontal cortex, changes resulting from experiencing traumatic events may

include hyperactivity in emotional processing frontal-subcortical circuits, which include

projections to the ventrolateral PFC and medial PFC, and decreased activity in the dorsal lateral

PFC, which is associated with executive functioning capabilities (Dolcos & McCarthy, 2006). In

the daily lives of those who have experienced trauma, these changes to affective-cognitive

processing circuits may present as difficulty effectively making decisions, problem solving, and

gauging risk and reward in situations with high-perceived emotional valence. Those who have

experienced trauma may use an avoidance strategy to attempt to circumvent high affective cues

that may cause emotional activation resulting in inhibition of cognitive processes. However, this

avoidance may result in both missing out on rewarding and positive aspects of one’s life and

gaining new experiences to help them relearn how to effectively process affective-cognitive

information (Aupperle, Melrose, Stein, & Paulus, 2011).

As suggested previously, hot executive functioning in trauma victims is typically

assessed using tests that require the participant to perform executive functioning tasks that

10

incorporate negative emotional stimuli. These stimuli may either consist of imagery or words

directly associated with trauma, or non-trauma specific negative emotion-laden cues. The most

commonly used task in hot executive functioning research and assessment with this population is

the Emotional Stroop task. Results from trauma-based Emotional Stroop testing demonstrate that

individuals who have experienced trauma focus more attention on trauma-related words than do

those with no trauma history (Williams, Mathews, & MacLeod, 1996; Moradi, Taghavi, Neshat

Doost, Yule, & Dalgleish, 1999; Ashley, Honzel, Larsen, Justus, & Swick, 2013; Caparos &

Blanchette, 2014). This failure of inhibition on the Emotional Stroop task suggests past traumatic

experiences have an effect on cognitive-affective processing in such a way that strong emotional

reactions down-regulate the ability to direct supervisory attention and effectively perform

inhibition, which is a major component of executive functioning (Ben-Haim, Mama, Icht, &

Algom, 2013). It is important to note, however, that most studies focus on individuals who are

seeking treatment for PTSD, and less is known about hot executive functioning and Emotional

Stroop results in those with sub-clinical trauma symptom manifestations.

The Emotional Stroop task can provide information on how an individual who has

experienced trauma is able to functionally inhibit an emotional reaction and divert attention away

from a negative valence cue and to an executive functioning task. It can be especially beneficial

in testing trauma victims because of its ability to present words specific to a certain person or

group’s trauma experience. For example, the Emotional Stroop may present words related to

sexual-assault for victims of rape or other sexual crimes (Caparos & Blanchette, 2014), while it

can show veterans words related to war and combat (Ashley, Honzel, Larsen, Justus, & Swick,

2013). While this individualized approach decreases generalizability of responses to specific

items, it allows for the induction of a heightened emotional impact and therefore the testing of

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person-specific trauma content. This approach may provide vital information on how those who

have experienced trauma react when confronted with specific emotion-triggering words, and the

overall reaction across groups of individuals, rather than specific content, can be generalized to

larger populations.

Its simple administration, adaptability, and precise response time outcome measures

make the Emotional Stroop task a useful tool in assessing how cognitive functions operate in the

presence of high emotional salience within a population that has experienced trauma. However,

the task also has areas in need of improvement. The words presented provide a fairly simple

representation of emotion-laden information. This simplicity detracts from the Emotional Stroop

task’s ability to measure responses to a broad range of levels of emotional salience, and affective

information that is more present in the general population. For example, individuals in real-world

environments may be faced with complex affectively-salient situations while planning walking

routes home in unfamiliar areas, when interacting in business or casual situations with others

who have reminiscent features of one’s trauma perpetrator, or when driving following a

traumatic crash. Though the Emotional Stroop task is able to present negative and trauma-related

words, traumatic situations contain more complex information than can be provided by word

presentation within this task.

The present study utilized the Emotional Stroop task to assess a sample with trauma

history in the general population in order to add to the already expansive literature on those with

PTSD. Additionally, it sought to augment the complexity of stimulus presentation in the

Emotional Stroop task by modifying an Implicit Trauma Association Test for hot cognitive

processing assessment.

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Implicit Association Tests for Cognitive Research

Implicit Association Tests (IAT) were originally developed within social psychology to

assess people’s biases using an automaticity-based functional task (Greenwald, McGhee, &

Schwartz, 1998). Since most attitudes or biases are typically evaluated using face valid self-

reports that can be manipulated by participants to show themselves in a good light, the IAT

offers a novel avenue of assessment to avoid such invalid responding. Within the task,

participants use a left or right response key to sort stimuli into categories. The outcome measure

of response time is used to examine how quickly individuals are able to assign a category to a

stimulus. The theory behind an IAT is that higher response times suggest a less automatic, more

controlled response that contradicts one’s natural inclination and attitude.

A strength of implicit tests is that a wide range of stimuli can be employed to assess

various attitudes over a large number of groups, objects, and feelings. By manipulating the

stimuli of the IAT to reflect the construct being studied, this test has been useful in performing

research on racial attitudes (McConnell, Allen, & Leibold, 2001; Xu, Nosek, & Greenwald,

2014), alcohol associations (Thush et al, 2008), views on both illicit (Ames et al, 2013) and

performance-enhancing (Brand, Heck, & Zieglar, 2014) drugs, disability perceptions (Coleman,

Ingram, Bays, Joy-Gaba, & Boone, 2015), alliance with rape myths (Widman & Olson, 2013),

shame (Rusch et al, 2007), and hundreds of other concepts.

While originally developed for social psychology research, inherent executive

functioning demands of the Implicit Association Test make it a potentially useful tool in

neurocognitive research. As in the Stroop task, participants completing an IAT must exert

executive control when performing the categorization task consisting of stimuli with varying

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levels of incongruence. Also as in the Stroop task, executive functioning capability is measured

by a response time variable. Comparisons between a race bias IAT and traditional executive

functioning tasks suggest IAT control may not only be a function of inhibition, but may also

require updating and set-shifting specific executive functions (Ito et al, 2015). In this way,

executive functioning demands may in fact be higher in for an IAT than the traditional Stroop

task, as task-set switching between trials on the IAT adds another layer of executive functioning

demands on top of the preexisting demands of inhibition and attentional control (Klauer, Schmitz,

Teige-Mocigemba, & Voss, 2010). In this way, the IAT may more closely resemble what have

been referred to as advanced Stroop tasks that include a measure of task-switching, generally

represented as instructions to switch between reading the color of the word (inhibition/controlled

processing) and reading the letters of the word (a more automatic process). However, since

reliable norms and validity measures within each executive function domain assessed by the IAT

have not yet been established, these executive processes can only be observed and described

together in terms of response time, without parsing out effects of specific executive actions as the

Stroop task does.

Functional MRI data from the original IAT paradigm supports its ability to assess higher-

order functioning in the prefrontal cortex and associated circuits. When performing a basic IAT

with low emotional salience (with words like flower and insect), the dorsolateral prefrontal

cortex, and to a lesser extent the anterior cingulate cortex, are activated, reflecting the occurrence

of executive processing (Chee, Sriram, Soon, & Lee, 2000). These fMRI findings are consistent

with activation seen in more traditional cool executive functioning tasks, including the traditional

Stroop task.

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In addition to its increased requirement of executive control, stimuli in the IAT may be

enhanced to be highly emotionally salient, adding a task demand of affective control and

enabling the task to measure how individuals perform executive functions with high emotional

load. These stimuli may include graphic images that are more complex than those found in other

tasks examining emotion and cognition, and able to exert more influence on the emotional part of

the affect-cognition link in hot executive functioning. For example, scenes depicting sexual

assault have been incorporated into an IAT examining attitudes toward rape (Widman & Olson,

2013), building on the Emotional Stroop task, which would traditionally present only words

related to assault. This more graphic depiction not only causes higher levels of affective arousal,

but also allows for study of how one may act when faced with a life-like situation, thus

increasing ecological validity of the task.

Functional imaging research suggests brain regions used while performing IATs with

high emotional salience are the same activated during other tasks requiring hot executive

functioning. Specifically, the orbitofrontal cortex and amygdala are activated in IATs with high

intensity stimuli, but not in those with low intensity stimuli (Luo et al, 2006). These fMRI

results, when looked at with data from the original low emotionally salient task, demonstrate

differences in brain regions associated with executive functioning paired with high emotion

versus purely cognitive executive functioning, and is consistent with findings from traditional

measures of hot and cool executive functioning.

Since trauma victims often show poor attentional control when presented with

emotionally salient stimuli and negative effects of emotional arousal on cognitive abilities, this

population is one that can be profitably assessed to help provide potential insights on the nature

of hot and cold EF tasks using IATs. However, thus far few studies have used the IAT to study

15

individuals who have experienced trauma. Those that have used this measure with samples who

have experienced trauma have tended to limit their sample to a specific type of trauma. Further,

these studies have examined such concepts as self esteem (Roth, Steffens, Morina, & Stangier,

2012) and emotional vulnerability (Engelhard, Huijding, van den Hout, & de Jong, 2007), with

scant research based on IATs as a measure of executive functioning in traumatized samples.

Research that has examined aspects of trauma using an IAT include a study looking at the

impact of sexual trauma history on the association between sexual and aggressive concepts

(Reed, McGrath, & Arlemi, 2011), which utilized an IAT consisting of aggressive and sexual

stimuli. While this research was useful in understanding how some trauma victims cognitively

associate concepts, its sample was limited to only victims of sexual trauma, and it did not

examine the inhibition, updating, and set-shifting executive task demands of the IAT. An

examination of the link between childhood trauma and depressive cognitions also used an IAT as

a primary outcome measure (Johnson, Benas, & Gibb, 2011). This study too, though, limited its

sample to a specific subset of trauma victims, and primarily studied mood cognitions instead of

executive functions. Negative self-appraisal biases in individuals with PTSD were examined

using a Traumatized Self Implicit Association Task (Lindgren, Kaysen, Werntz, Gasser, &

Teachman, 2013), but again executive functioning demands of the task were not investigated or

discussed within this study. The present study sought to add to the limited literature on IAT

performance in those who have experienced trauma within the general population, and

specifically modify an Implicit Association Test to examine executive functioning capabilities.

The Current Study

The current study was designed to investigate executive functioning in individuals within

the general population who have experienced traumatic events. Research on PTSD patients

16

reveals those who have experienced trauma may be susceptible to deficits in two types of

executive functioning: cool, purely higher order cognition, and hot processes that integrate

highly salient affective information and motivation into planning, organization, inhibition and

other executive tasks. While this research provides insight into trauma’s potential effects on hot

and cool executive functions, PTSD patients represent only a small subset of the approximately

60 percent of the population who have experienced trauma. Moreover, little research has

examined a broader range of trauma victims who do not manifest the full set of symptoms

required for a diagnosis of PTSD. This study sought to expand on the current trauma literature by

investigating how problems in hot and cold EF may present in those with sub-clinical trauma

symptoms.

To assess for EF deficits, the traditional Stroop task and modified Emotional Stroop task

were utilized. While the classic Stroop task assesses inhibition in neutral situations free of

emotional content, the Emotional Stroop test measures how well a person with a trauma history

is able to manage their attentional focus and move it away from highly emotional words and to

the task at hand.

Additionally, the present study used a modified Implicit Association Test as a novel

measure aimed to supplement the Stroop and Emotional Stroop tests of executive functioning.

While the Stroop and Emotional Stroop tasks are able to provide important assessment

information, they each consist of simple stimuli and measure only a limited range of executive

functions. The Implicit Association Test is becoming more prevalent in neuropsychology

research due to its ability to assess inhibition, updating, and set-shifting either with or without

the impact of emotional stimuli. The IAT has potential in the area of executive assessment

following trauma, but thus far has been used only in narrow trauma samples and primarily in

17

studies of mood symptoms, cognitive associations with violence, and self-esteem. When used

within a neuropsychology framework, it is possible that individuals who have experienced

trauma executive difficulties with inhibition may be especially prevalent in the IAT, consistent

with literature from the traditional Stroop and Emotional Stroop tasks.

By using a novel Implicit Association test for Trauma along with the Stroop Color and

Word test and Emotional Stroop test in the assessment of individuals with varying degrees of

trauma history and acute trauma symptom presentation, the current study sought to add to

literature on executive functioning following trauma.

It was hypothesized that:

1) Participants who have experienced trauma will perform significantly worse on both a

traditional and an Emotional Stroop task than a trauma-naïve group.

2) The trauma group will also perform worse on a novel modified Implicit Trauma Association

Test than a control group.

3) More traumatic events reported on the Trauma History Questionnaire and higher reports of

trauma symptoms on the PTSD Checklist will correlate with poorer performance on the

traditional measures of executive functioning (Stroop task and Emotional Stroop task) and a

novel measure of hot executive functioning (Implicit Trauma Association Test).

4) Performance on the Implicit Association Test will correlate with both cool and hot measures

of executive functioning in the total sample of individuals either with or without trauma

experiences.

METHOD

This study utilized the Stroop Color and Word test, Emotional Stroop test, and a novel modified

Implicit Association Test to assess executive functioning in individuals who have experienced

18

trauma. Performance on the three tasks as well as self-reports of trauma history and trauma

symptoms were analyzed to examine how individuals who have experienced trauma differ from

those who have not in the executive processing of neutral and emotionally salient stimuli.

Additionally, the Implicit Association Task was compared to self-reports of trauma experience

and results on the two Stroop tasks to assess its utility as a measure of executive functioning in

this population.

Online Platform: MTurk

To gather data from the general population, the online survey website Amazon Mechanical Turk

(MTurk) was utilized. On this website, individuals respond to pre-selected surveys and tasks, and

are compensated with a nominal fee. The primary aim in using MTurk was to assess a relatively

large and diverse general community sample, thus increasing generalizability to the larger

population. The MTurk platform has been shown to provide reliable and valid survey data while

also offering the opportunity to examine individuals from the general population (Buhrmester,

Kwang, & Gosling, 2011). Additionally, preliminary use of this platform for cognitive testing

has revealed validity comparable to in-person testing (Crump, McDonnell, & Gureckis, 2013).

Payment for participation was determined based on approximate task completion time, and was

set at $3 per participant.

Participants

Data was collected from 120 participants on the survey website MTurk. Participants were

residents of the United States who were certified as “Master Workers” on the MTurk platform.

This title reflects both a large number of prior tasks completed and a history of positive approval

ratings. Since this study aimed to assess trauma within the general population, no further

parameters were set for participant recruitment.

19

Of the 120 participants who completed the study, 16 were excluded from data analysis

due to incomplete data, ineligibility due to age or neurological condition, or poor effort on

cognitive tasks. Therefore, the final sample size consisted of 104 participants. Of the 104

participants, 46 (44.2%) were male and 58 (55.8%) were female. Age of participants ranged from

21 to 64 years old, with a mean age of 37.5 years (SD=10.58). In terms of ethnicity, the sample

was 88.5% White, 4.8% Black, 2.9% Pacific Islander, 1.9% Hispanic, 1.0% Asian, and 1.0%

Other. All participants had obtained a high school diploma or GED, and 47.1% had a bachelor or

graduate degree.

Measures

Demographic and Health Questionnaires

Participants completed a demographics questionnaire with the following information: age,

sex, years of education, race/ethnicity, and native language. Additionally, they completed a

medical/neurological condition question indicating history or presence of the following

conditions: seizure, head injury, loss of consciousness, other neurological disorders, and vision

problems including colorblindness.

Trauma History Questionnaire (THQ)

To assess trauma history, the Trauma History Questionnaire (THQ; Green, 1996) was

used. This self-report assessment of trauma experience asks participants to indicate whether a

series of specific events have occurred in their lifetime. The THQ utilizes a yes/no response

format to examine history of crime-related events, general disasters and trauma, and physical and

sexual experiences. It also assesses frequency of trauma and ages at which the trauma(s)

occurred with a free-response format. Test-retest reliability of items on the THQ suggests

stability is high for specific events such as being attacked by a weapon (.90) and being robbed

20

(.91). This reliability is lower, but still in a fair to adequate range, for more general categories

such as those assessing witnessing a trauma inflicted on another person. Content validity is also

high on the THQ, established by agreement by instrument developers on appropriate items,

basing the THQ on previous measures, and the instruments’ consistency with the DSM’s

criterion A stressors (Hooper, Stockton, Krupnick, & Green, 2011).

The THQ provided criteria for participants to be separated into “trauma” and “no trauma”

groups based on their endorsement of any past traumatic events. Additionally, it provided

information on the number of events experienced, allowing for correlation analysis between

frequency of trauma events and cognitive abilities. The range of items assessed through this

measure provided information leading to categorization, which divided participants into groups

based on their specific type of traumatic history, allowing for analysis of the relationship

between trauma type and affective/cognitive processing.

PTSD Checklist – Civilian Version (PCL-C)

The present study sought to examine individuals with traumatic history and post-trauma

symptoms within the general population. To assess presence and severity of current post-

traumatic symptoms, the PTSD Checklist – Civilian Version (Weathers, Huska, & Keane, 1991)

was given. This 17-item self-report inventory asks participants to respond to questions regarding

how much they have experienced post-traumatic symptoms in the last month. Items on the PCL-

C are answered on a scale ranging from (1) Not at All to (5) Extremely. The PCL-C has

demonstrated adequate test-retest reliability in the .75 to .88 range, internal consistency

above .90 when used with varying traumatized populations, and high convergent validity with

other measures of PTSD symptoms, including the Clinician-Administered PTSD Scale (CAPS)

and Mississippi PTSD Scale (MS) (Wilkins, Lang, & Norman, 2011). A total symptom severity

21

score was derived by summing the scores from each of the 17 questionnaire items. This score

was then used in analyses to determine the relationship between post-traumatic symptoms and

cognitive functioning.

Eysenck Personality Questionnaire Revised Abbreviated (EPQR-A)

Neuroticism often varies in relation to trauma exposure (Ogle, Rubin, & Siegler, 2014).

The present study aimed to assess the relationship between traumatic experiences and executive

functioning, while also accounting for the potential negative effects of neuroticism of PTSD

symptoms and/or cognitive processing. In order to assess for neurotic traits, the Eysenck

Personality Questionnaire was administered. This 6-question assessment asks participants to

endorse how much they agree with statements related to their mood, nerves, and personality.

Total score from the assessment ranges from 6 to 24, with higher scores indicating more

neuroticism symptoms.

Stroop Color and Word Test

To assess executive functioning, a computerized version of the Stroop Color and Word

Test was administered. The Stroop task has been repeatedly validated over the past century and

found to be psychometrically sound in multiple-item presentations and single-item presentations

such as that was used in the present study (MacLeod, 1991). Additionally, computerized and

web-based Stroop tasks such as the one used in this study have maintained the strong

psychometric properties of the original task, with various studies citing validity estimates of .65

and above (Reeves et al, 2007; Silverstein et al, 2007). This task presents stimuli in a single-item

format across three subtests: color recognition, word reading, and color-word interference. On

the color recognition task, neutral stimuli were presented in red, green, and blue colors. The

participant responded to each stimulus according to what color it was by pressing a pre-assigned

22

key. The word reading task presents the words “red,” “green,” and “blue” written in congruent

ink. The participant is asked to respond to what each stimulus says by pressing a pre-assigned

key.

The color-word interference task presents the words “red,” “green,” and “blue,” written

in incongruent colors of ink. The participant must respond to the ink color, while ignoring word

meaning. Key assignments for red, green, and blue responses are stable throughout the three

tasks, and participants are instructed to respond to each stimulus as quickly and accurately as

possible. Response time was examined as the primary measure of the task.

Emotional Stroop Test

In order to assess attentional control and inhibition under conditions of emotional arousal,

an Emotional Stroop Test was administered. Computerized and Emotional Stroop paradigms like

the one used in this study have shown to reliably measure interference in various populations,

including those with anxiety, PTSD, panic disorder, and depression (Williams, Mathews, &

Macleod, 1996). The Emotional Stroop task will present four blocks of colored words: (1)

neutral words with no emotional valence (i.e. ceiling, lettuce, Indiana), (2) positive words (i.e.

happy, smile, award), (3) negative non-trauma related words (stupid, tragedy, disappointment),

and (4) negative trauma related words (rape, attack, abuse). To slightly alter task demands in

order to reduce practice effects, words were presented in a different combination of colors from

the traditional Stroop task. The colors yellow, pink, and blue were used, and participants were

asked to respond as quickly as possible to the color of the ink. Response time and accuracy was

examined as the primary measure of the task, and was compared both within-task (between

blocks) and between-tasks with the traditional Stroop task.

23

Implicit Association Test of Trauma

A novel Implicit Association Test of Trauma was developed and administered to assess

attentional bias, inhibition, and task switching under conditions of emotional arousal. This task

incorporated sequencing features of the traditional Implicit Association Test while adding

additional congruent and incongruent response demands derived from Stroop paradigms. The

novel IAT was developed based on the following schematic illustration (Greenwald, McGhee, &

Schwartz, 1998), and adjusted to represent emotionally salient situations and more closely tap

into executive processes:

Figure 1. An illustration of the 5 sequences of the Implicit Association Test

For each of the five sequences of the modified IAT, four types of stimuli were used.

These stimuli replicated the four categories of stimuli used in the Emotional Stroop task, but

were represented by pictures instead of words: (1) Neutral pictures (i.e. furniture, food items), (2)

Pleasant pictures (i.e. a person smiling, a rainbow), (3) Trauma-related unpleasant pictures (i.e.

car accidents, explosions, assaults), and (4) Unpleasant pictures not related to trauma (i.e. poison,

a “Danger” sign, a storm cloud). Stimuli from each category were represented in an equal

24

number of black-and-white and color images, and were equally distributed across the five

sequences of the IAT.

During the first sequence of the Implicit Association Test, participants were instructed to

label stimuli into two categories according to their color attributes. These categories were each

assigned to an arrow key and displayed at the top of the screen: (Left) Black-and-White and

(Right) Color. In the second sequence, participants sorted stimuli into categories according to

their adverse properties in the following manner: (Left) Unpleasant and (Right) Neutral/Pleasant.

The third sequence represented a congruent task. In this sequence, participants were instructed to

sort stimuli into categories based on their color features, with response options displayed at the

top of the screen. These options replicated the previous key response options: (Left) Black-and-

White & Unpleasant and (Right) Color & Neutral/Pleasant. Since this is a congruent task,

options displayed at the top of the screen paired attribute responses (unpleasant or

neutral/pleasant) with color responses (black-and-white or color) consistent with the stimulus

presented. In other words, Black-and-White photos were unpleasant and color photos were

neutral or pleasant.

In the fourth sequence, the response keys for pleasant and neutral/unpleasant stimuli were

reversed: (Left) Neutral/Pleasant and (Right) Unpleasant. The fifth task again asked participants

to sort pictures according to their color, but had reversed pairings from the third sequence: (Left)

Black-and-White & Neutral/Pleasant and (Right) Color & Unpleasant. This task was incongruent

in its presentation of response options. Specifically, unpleasant photos were presented in black-

and-white, and neutral or pleasant photos were in color. Response time in sorting each type of

picture across each of the five sequences was examined as the primary measure of this modified

IAT task.

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Referrals

Tasks within the current study presented trauma-related words and images to participants.

Due to the potential for strong emotional responses from participants, referrals to support

hotlines were made available following the completion of the study if participants found that

helpful. These referrals included phone numbers and websites for the National Sexual Assault

Online Hotline, the Veterans Crisis Line, the Safe Online Helpline, and the National Suicide

Prevention Lifeline.

Procedure

Internal Review Board (IRB) approval was received from the University of North Texas

prior to the start of the study. Once the study was published to the MTurk website, Master

Workers were able to review the informed consent notice to determine whether to accept or

decline to participate. Upon placing an electronic signature on the informed consent form,

participants were given instructions to complete the questionnaires. Questionnaires were

presented in the following order: demographic and health questionnaires, THQ, PCL-C, and

EPQR-A.

Following completion of the questionnaires, participants were provided a link to

complete the cognitive tasks. This link was directed to the Inquisit Millisecond website, where

participants were able to access the three cognitive tasks. The Stroop Task was presented first,

followed by the Emotional Stroop Task, and the IAT. Upon completion of the IAT, participants

were instructed to return to the MTurk study page, where they were provided with a list of

referrals and were able to submit the task in order to receive compensation.

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RESULTS

Analytic Approach

The aim of data analysis was to delineate the effect of traumatic experiences on executive

functioning, specifically cool cognitive processing and hot emotional/cognitive processing. To

evaluate this hypothesis, participants were divided into 2 groups based on their responses to the

Trauma History Questionnaire. Participants who did not endorse any traumatic events comprised

the “no trauma” group, while those who endorsed one or more traumatic events were placed in

the “trauma” group. The “no trauma” group consisted of 23 participants (mean age = 33.47 years,

SD = 10.56), while the “trauma” group had 81 participants (mean age = 38.64; SD = 10.37). A

Chi-Square analysis indicated that there was no significant difference (X2(1) = .755 p > .05) in

the proportions males and females in the no trauma group (48% females) versus the trauma

group (58% females). However, an ANOVA revealed there was a significant age difference

between groups, F=4.406, p<.05. Table 1 shows the demographic variables for the total sample,

and also the trauma versus non-trauma groups.

Initial analyses were performed on these groups in order to examine the relationship

between trauma and cognitive task performance. Since accuracy scores were consistently high

within the sample, response time provided the greatest source of information for analysis. Due to

the difference in age between the groups, age was controlled for in analyses of group differences.

Since education level did not significantly differ between the two groups, and because further

analyses revealed no significant relationship between education and performance, education

level was not controlled for in analyses.

To further investigate the complex relationship between trauma and cognition, as well as

the potential compounding effect between multiple traumatic experiences and cognitive

27

processing, a dimensional approach was also employed. This approach initially utilized Pearson

correlations to examine the relationship between number of traumatic items endorsed on the

THQ and both hot and cool executive functioning task performance. Table 2 outlines the

descriptive statistics, along with the skewness and kurtosis, for trauma and non-trauma groups, as

well as the total sample on traditional EF measures. Because skewness and kurtosis values

represented significant departures from normality, nonparametric analyses were additionally

employed to provide more robust estimates of variable associations. However, in dimensional

analyses where age was predicted to have a significant impact on data, nonparametric

correlations were replaced with age-controlled partial correlations.

Finally, males and females may be differentially affected by trauma. To examine the

unique relationship between trauma experience and executive functioning within each sex,

further non-parametric correlations were employed. Table 3 provides demographic information

separately for male and females. Descriptive statistics, including skewness and kurtosis, for each

sex are provided in Table 4.

Addressing Data Issues

Of the 120 participants who completed the study, data was excluded for 16. Of these 16 excluded

participants, 4 were repeat participants who attempted to complete the study twice. 1 participant

was over the 65-year-old age limit. Three participants declined to enter their age, and considering

the close relationship between age and cognitive ability, were excluded from the final sample.

An additional 2 excluded participants had low accuracy scores, reflecting poor effort on

executive functioning tasks. The 6 remaining participants who were excluded from the final

sample had missing cognitive data.

Regarding the missing cognitive data, computerized testing like that used in the present

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study results in a large number of variables being recorded. Additionally, participants in the

current study used various browsers and operating systems that added to the complexity of data

recording. These factors likely contributed to the missing cognitive data from 6 participants.

Because any missing response data likely resulted from computerized error or saving error,

missing data was hypothesized to be unbiased toward a certain demographic or performance

level.

This hypothesis was largely supported by t-tests performed between included participants

and those excluded due to missing cognitive data, which revealed no significant differences in

sex (t = -.216), age (t = .625), education (t = -.487), or score on THQ (t = -.384), PCL-C (t

= .583), or EPQR-A (t = -.644) measures. However, there was a moderate difference in ethnicity

representation between included and excluded participants (t = 1.991, p < .05). When those

excluded due to missing age responses where included in missing data t-tests, there were no

significant differences in these demographic or survey variables. To account for missing data, a

list-wise deletion approach was used in data analysis, excluding all data for participants with

incomplete measures.

Analysis of Hypotheses

Hypothesis 1: Participants who have experienced trauma will perform significantly worse on

both a traditional and an Emotional Stroop task than a trauma-naïve group

The first hypothesis predicted that participants who endorse a history of traumatic experiences

would perform worse on both traditional cool and hot measures of executive functioning. An

ANOVA was performed to assess differences between the trauma and no trauma groups on

executive task performance. Due to group differences in age, and because age can have a

significant impact on cognitive task performance, the analysis was performed with age as a

29

control variable. The ANOVA revealed no significant differences between the two groups in

terms of response time on Stroop or Emotional Stroop interference tasks.

Hypothesis 2: The trauma group will also perform worse on a novel modified Implicit Trauma

Association Test than a control group

The novel Implicit Trauma Association Test aimed to utilize elements from the traditional IAT

and Stroop task in order to assess executive functioning. However, an ANOVA revealed no

significant differences between groups on this novel task.

Hypothesis 3: More traumatic events reported on the Trauma History Questionnaire and

higher reports of trauma symptoms on the PTSD Checklist will correlate with poorer

performance on the traditional measures of executive functioning (Stroop task and Emotional

Stroop task) and novel measure of hot executive functioning (Implicit Trauma Association

Test)

The third hypothesis predicted correlations between raw scores on the PCL-C and THQ and the

response time performance indicator on the traditional Stroop task, Emotional Stroop task, and

Implicit Trauma Association Test. This hypothesis suggested that as raw scores on the

questionnaires increase, response times on the primary interference conditions of the executive

functioning tasks should also increase. Pearson and nonparametric (Spearman’s Rho)

correlations between the cognitive and trauma-related variables were initially performed.

However, in light of the impact of between-group differences of age on ANOVA results from

Hypothesis 1, additional correlations were performed as partial correlations controlling for age.

Since results from a nonparametric approach did not demonstrate large deviations from Pearson

correlations, partial Pearson correlations appeared to be the most-sound approach to analyzing

30

this hypothesis. Table 5 outlines results from Pearson, non-parametric, and partial Pearson

correlations for traditional Stroop and Emotional Stroop tasks.

Initial non-parametric correlations revealed that the number of unique trauma events

endorsed on the Trauma History Questionnaire was significantly correlated with Stroop

interference response time, rS = .31, p < .01, and Emotional Stroop interference response time,

rS= .29, p < .01. With regard to post-trauma symptoms, results revealed a significant correlation

between PCL-C score and traditional Stroop interference response time, rS = .23, p < .05. When

age was controlled for, both the number of trauma experiences and PCL-C score were

significantly correlated with interference response time on the Stroop task (r = .22, p < .05 & r

= .41, p< .001). However, there was no significant correlation between either trauma experiences

or post-trauma symptoms and Emotional Stroop interference.

Overall, there appeared to be significant relationships between EF variables and trauma

experience for the sample, as evidenced by initial analysis results. To further examine this

relationship, a path model was developed. This model analyzed the relationship between trauma

measures (number of traumas endorsed on the THQ and symptoms described in the PCL-C) and

executive functioning performance. This model is represented in Figure 2. This model

demonstrated that, when age and non-normal data are controlled for, there is a relationship

between PCL-C scores and traditional Stroop interference. Additionally, the number of unique

traumas experienced by the sample is related to performance on the Emotional Stroop in

response to negative words.

With regard to the novel IAT task, non-parametric and age-controlled partial correlations

revealed no significant correlation between any of the 5 IAT sequences and THQ or PCL-C

scores.

31

Hypothesis 4: Performance on the Implicit Association Test will correlate with both cool and

hot measures of executive functioning, regardless of trauma experience

Hypothesis 4 addresses predicted convergent validity between the novel Implicit Association

Test and the traditional measures of executive function used in this study. This correlation was

hypothesized to present in those with trauma experience and those within the non-trauma group.

To test this hypothesis, a series of non-parametric correlations were performed examining

the relationship between response time on tasks within the IAT and those within the traditional

and Emotional Stroop tasks. Table 6 demonstrates the results from these analyses. The

widespread correlation between IAT tasks and different tasks of traditional EF measures display

no discernable pattern to support the convergent validity between different IAT tasks and

traditional executive functioning tasks.

Additional Analyses

In addition to exploring the initial hypotheses, subsequent analyses were performed in

order to better understand the relationship between sex, trauma history, and executive task

performance. Furthermore, the relationship between type of traumatic experience and executive

functioning performance was investigated.

The Relationship between Trauma History and Performance on Executive Functioning Tasks,

Examined Independently for Males and Females

Males and females may be differentially affected by trauma, in terms of frequency of

traumatic events, type of trauma experienced, and both emotional and cognitive reaction to

trauma. Therefore, additional analyses were performed in order to separately examine effects of

trauma on executive functioning in the female group (n = 58; mean age = 38.81, SD = 10.96) and

32

male group (n = 46; mean age = 35.85 years, SD = 9.95). Notably, a t-test revealed no significant

age difference between the female and male groups, t(102) = 1.425, p >.05.

To understand the dimensional nature of trauma effects within each sex, both

nonparametric and partial correlations were performed for both males and females. Results are

outlined in Tables 7 and 8. Spearman’s rho values demonstrate that the number of traumatic

experiences was correlated with Emotional Stroop interference response time, rS = .321, p < .05.

This finding was consistent in partial correlation results where age was controlled, r = .266, p

< .05. Additionally, the correlation between the number of traumas experienced and Stroop

interference response time was significant in partial correlation results, r = .279, p < .05, and

approached significance in nonparametric analysis, rS = .251, p = .058,

In terms of specific categories of emotional stimuli, higher number of traumatic

experiences was significantly correlated with increased response time to both traumatic, rS = .300,

p < .05, and negative, rS = .398, p< .01, Emotional Stroop stimuli, though when age was

controlled for only negative stimuli held significance, r = .273, p < .05. With regard to post-

trauma symptoms, PCL-C score was significantly correlated with both measures of executive

functioning in partial correlations (Stroop interference: r = .588, p < .001; Emotional Stroop

interference: r = .315, p < .05) and with interference response time to traumatic Emotional

Stroop stimuli in nonparametric analysis, rS = .269, p<.05.

A path model was employed to further examine the relationship between trauma and

executive functioning in females. Figure 3 demonstrates this model. When neuroticism scores,

age, and non-normal data are accounted for, there continues to be a significant relationship

between PCL-C scores and both traditional and Emotional Stroop interference response times.

33

Additionally, the number of traumas endorsed is correlated with response time to negative words

on the Emotional Stroop task.

Results from the male sample revealed a significant nonparametric correlation between

the number of traumatic experiences and traditional Stroop interference, rS = .364, p < .05, but

not Emotional Stroop interference. PCL-C score analyses also revealed a significant correlation

between post-trauma symptoms and Stroop interference response time, rS = .316, p<.05.

However, these results appeared to be largely attributed to age, as they did not hold significance

in partial correlations or path modeling (Figure 4).

The Relationship between Type of Traumatic Experience and Executive Functioning

Performance

Four categories of traumatic experiences were derived from questions on the THQ. The

categories were classified as “Assault, Injury, and Illness,” “Theft and Crime,” “Natural Disaster

and Motor Vehicle Accident (MVA),” and “Witness,” a category which incorporated traumatic

events in which the person observed a traumatizing sight or learned of a traumatic loss. Items

associated with each category are outlined in Table 9.

Due to the sex differences in correlations between trauma and executive functioning

measures apparent in the previous set of analyses, the relationship between each of these

categories and EF measures was analyzed separately for males and females. Again, both non-

parametric and partial correlations were performed in order to best analyze the data while

accounting for non-normality and age effects. Results from these correlations are outlined in

Tables 10 and 11.

For females, those who had experienced traumatic events within the “witness” category

had the most significant correlation between trauma experience and measures of executive

34

functioning. Partial correlations revealed significant relationships between the number of

traumatic experiences in this category and interference measures of both the traditional, r = .288,

p < 05, and Emotional Stroop task, r = .319, p < .05. Additionally, for women, the number of

experiences within the witness category was significantly correlated with response time to

negative stimuli on the Emotional Stroop task, r = .294, p < .05. Non-parametric correlations,

which did not account for age, largely supported these results, specifically in terms of Emotional

Stroop performance.

Males again showed fewer significant interactions between trauma and executive

functioning measures when individual trauma categories were examined. However, both partial

and non-parametric correlations suggest a relationship between the Assault/Injury/Illness

category of trauma experiences and increased response time to the interference category of the

traditional Stroop task (r = .332, p < .05; rS = .417, p < .01).

DISCUSSION

The present study investigated the relationship between traumatic experiences and

executive functioning. While much trauma research is performed on special populations with

diagnosed posttraumatic stress disorder, the present study sought to advance understanding of the

dimensional nature of trauma by collecting data from individuals within the general population.

Specifically, “cool,” purely cognitive executive functions and hot executive functions combining

high affective salience with cognitive demands were examined within the population. The

platform Amazon Mechanical Turk was utilized to sample from a diverse group of individuals

with varying demographic features and histories of traumatic experiences. Use of this survey

domain added additional novelty to the current study, as cognitive research is only recently

gaining widespread use on this medium.

35

Primary Findings

Trauma Experience and Post-Trauma Symptoms may Impact both Cool and Hot Executive

Functioning

The number of traumas endorsed, as well as the post-trauma symptoms reported, varied

throughout the sample. To examine the relationship between multiple traumas, post-trauma

symptom presentation, and executive functioning, dimensional analyses were performed. Results

from these analyses suggest multiple traumas may have a compounding effect, with those who

have experienced more traumatic events showing greater difficulty with both hot and cool

executive functioning tasks. This result is consistent with current research on the severity of

cumulative and complex traumas (Karam et al, 2014), and suggests individuals who have

experienced a large number of traumatic events may be most at-risk for cognitive deficits

affecting daily functioning.

A similar relationship may exist between post-trauma symptoms and executive

functioning. Reports of more pervasive post-trauma symptoms appeared to be related to

difficulty with cool and hot executive functioning tasks. This was true for those across the vast

spectrum of post-trauma symptoms. These results are significant when viewed in the context of

the study of post-trauma cognition, which typically focuses heavily on those with diagnosed

PTSD. The present results suggest that while those who do not meet criteria for PTSD may have

less pronounced deficits, their executive functioning may still be meaningfully impacted.

Notably, trauma experiences and trauma symptoms were found to exhibit a more

significant relationship with cool executive functioning than hot executive functioning. While

affective, “hot,” cognitive functioning is more frequently studied in a trauma-impacted

36

population, the current results suggest that the impact on cool cognitive processes, such as

interference and task switching, warrants further investigation.

The Overall Cognitive Effect of Trauma may vary by Sex

Women are more at-risk for traumatic experiences than men, and literature suggests the

two sexes may also demonstrate different reactions and effects in response to trauma (Maguen,

Luxton, Skopp, & Madden, 2012). To examine potential differences in executive functioning

following trauma, further analyses were performed on questionnaire responses and cognitive data

from each of the sexes. Overall, women’s executive functioning was closely correlated with both

the number of traumatic experiences and post-trauma symptoms. This was the case for both hot

and cool executive functioning measures.

For the male sample, neither cool nor hot executive functioning varied in accordance with

traumatic events as it did for women. Additionally, post-trauma symptoms demonstrated no

significant relationship with executive functioning in males. These results suggest that, just as

women are more likely to develop PTSD following traumatic experiences, they may also be

more at-risk for executive deficits in the aftermath of traumatic events. These effects may be

widespread throughout areas of hot and cool executive functioning.

Executive Functioning in Men and Women may be Differentially Impacted by Types of Trauma

Further analyses were performed within each sex to examine the relationship between

specific types of trauma and executive functioning. Items within the Trauma History

Questionnaire were divided according to trauma type in order to better examine the effects of

different traumatic events. Results revealed that, for men and women, different types of trauma

were evidencing significant relationships with executive functioning performance.

37

Specifically, women who had experienced traumatic events involving witnessing

violence or death, or receiving news of the illness or death of a loved one, demonstrated the

greatest relationship between trauma experience and executive functioning performance. This

relationship was present in both cool and hot measures of functioning. Executive functioning

performance by males in the sample was less impacted overall by trauma. However, for males,

there was a significant relationship between experiences of assault, injury, or illness and

performance on the Stroop task.

These findings, when viewed along with preliminary dimensional analyses previously

discussed, suggest that not only may broadly defined trauma impact men and women differently,

but specific types of trauma may also differentially impact each sex. In the context of trauma

research, assessment, and treatment avenues, knowledge of what types of traumatic events may

be most influential to each sex could provide invaluable information for the management and

treatment of post-trauma difficulties. Therefore, this avenue of study warrants further

investigation and understanding.

The MTurk Platform Paired with Certain Executive Functioning Tasks May Provide a New

Avenue for Cognitive Research

While MTurk has traditionally been used to perform survey research, it is gaining

popularity within the study of cognition and neuropsychology. The present study paired the

MTurk survey platform with 3 cognitive tests. On the cognitive tasks, participants displayed high

percentages of correct responses, which would be expected from a general population sample

without neurological dysfunction. Though response time output from the novel IAT did not

support hypotheses about its use in assessing executive functioning, response times within the

38

traditional Stroop and Emotional Stroop tasks were within an expected range, and were able to

provide support consistent with literature on the effects of trauma on interference response times.

Further validation studies are needed to provide increased support for the utility of

MTurk in executive functioning research. However, preliminary results from the current study

provide supporting evidence for its use as a viable source of cognitive data from the general

population.

Future Directions

The present study suggests trauma may impact both cool and hot executive functioning

whether or not an individual meets full criteria for PTSD. With more than half the population

expected to experience a traumatic event within their lifetime, these results emphasize the need

for more research into the cognitive impact of trauma, both in clinical and non-clinical

populations. An increase in sample size within a general population study could build on the

current study’s results by increasing statistical power. Online sampling, such as that available

through MTurk, could provide an avenue to study a larger sample quickly and reliably. Though

potentially less time efficient, in-person survey and cognitive test administration within a diverse

general population sample could also provide further information on executive functioning in

those with a variety of trauma levels and post-trauma symptoms. Validity tests between in-

person study administration and that performed online could provide more support for the

validity of MTurk for cognitive research within a trauma-impacted population.

While a widespread approach to researching post-trauma executive functioning may

effectively reach a diverse population, certain risk factors may expose individuals to potentially

more significant cognitive impact. These risk factors include female gender and multiple trauma

experiences. Therefore, further research into the differential impact of trauma on men and

39

women, and specifically the risk factors associated with females, is needed. The relationship

between types of trauma (assault, death of a loved one, natural disaster, etc.) and executive

functioning in males and females may also be specifically examined within future research to

address initial findings that these types of traumas may impact the sexes differently. Furthermore,

the potential compounding effect of multiple traumas on both cool and hot executive functioning

warrants further investigation in both sexes.

Finally, the novel IAT used within this study aimed to increase ecological validity of

traditional measures of executive functioning. While preliminary results do not support this

specific test’s use in trauma-related cognitive research, the need for new, more ecologically valid

tests within the realm of neuropsychology remains. In the present study, performance on

interference conditions within the Stroop Task and Emotional Stroop Task was impacted by past

traumatic experiences. Supplementing this research with the use of more ecologically valid

measures may further delineate the specific areas of difficulty those who have a trauma history

experience, and increase understanding of how these difficulties translate into daily life.

Conclusions

In summary, results from a sample of individuals from the general population suggest

that as the number of traumatic experiences increases, the impact of trauma on both hot and cool

executive functioning may become more pronounced. Executive functioning in men and women

may be differentially impacted by trauma, with women’s trauma experiences and symptoms

demonstrating a stronger relationship with both cool and hot executive functioning. Additionally,

the specific type of traumatic experience may have an effect on cognitive functioning, and this

relationship may differ between the sexes.

40

The Amazon Mechanical Turk website provides a novel forum for survey and cognitive

research. The current study provides support for the ease of use of this medium, and also the

high-quality results it can provide. Future research validating its use compared to traditional in-

person paper-and-pencil and computerized assessment could provide greater evidence for its

utility. Further research could also build on the present study by increasing sample size, targeting

individuals with multiple traumas or specific traumas, providing more information on sex

differences in trauma impact, and generating more ecologically valid measures of executive

functioning.

41

TABLES AND FIGURES

42

43

44

45

46

47

48

49

Figure 2. Path Model Representing Relationship between Trauma and EF Measures

Figure 3. Path Model Representing Relationship between Trauma and EF Measures, Females

50

Figure 4. Path Model Representing Relationship between Trauma and EF Measures, Males

51

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