Stress in undergrads

LOCUS OF CONTROL PREDICTS CORTISOL REACTIVITY
AND SPEECH PERFORMANCE IN RESPONSE TO ACUTE
STRESS IN UNDERGRADUATE STUDENTS
Yvette Z. Szabo
University ofLouisville
A ndrew C hang
California State University, Los Angeles
Cheryl Chancellor-Freeland
San Jose State University
Abstract
Previous studies have found that an individual’s perception of control
in a situation (Locus of Control; LOC) can serve as a protective factor
that has physiological and psychological benefits. The present study
examines LOC in an acute stress paradigm to examine the relationship
between LOC and hypothalamic-pituitary-adrenal axis functioning
as well as between LOC and performance. One hundred and thirteen
participants at a metropolitan university were randomly assigned to ei
ther a stress or control condition. The stress condition consisted of the
Trier Social Stress Test (TSST) while the control condition consisted
of viewing a neutral travel video. Salivary cortisol was measured at
four time points before and after exposure to the assigned condition. A
mockjob interview speech in the TSST was recorded and evaluated for
performance on eight dimensions. LOC significantly predicted cortisol
reactivity to the stressor in a multiple linear regression model. In addi
tion, LOC was a significant predictor of speech performance in a sim
ple regression model. Cortisol was not related to speech performance,
and LOC did not moderate this relationship, although LOC uniquely
predicted speech performance. This research adds to a growing body
of literature demonstrating physiological and functional influences of
LOC orientation.
Keywords: locus of control, acute stress, cortisol, undergraduate stu
dents, Trier Social Stress Test, speech performance
225
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226 / College Student Journal
Although usually assumed to be only del
eterious, stress has the potential to enhance,
hinder or show no impact on the performance
of an individual. How well individuals do in
stressful situations, such as workplace perfor
mance reviews, test-taking, and formal pre
sentations often depend on their perception
of control and mastery. Stressful situations
also activate the acute stress response, known
as the body’s “fight or flight” response, a
physiological and psychological response to
physical and social demands. Many factors
may influence the impact of stress, including
detrimental or beneficial outcomes. Although
perception of mastery seems to play an im
portant role in success, it is not the only factor
that is influential because the biological stress
system may be still present and active. Both
perception of control and mastery and the bi
ological response have the potential to inter
fere with cognition and performance. While
the literatures in both camps have developed
separately, there is a need for understanding
in their integration.
An individual can view a situation as a
result of external or internal forces, known as
one’s Locus of Control (LOC). LOC scores
fall on a continuum between internal and
external orientations. Lower LOC scores,
or an internal orientation, indicate that one
feels self-empowered and in control of his
or her environment. Higher LOC scores, or
a more external orientation, indicate that the
individual feels they have less control of their
environment and that outside forces shape
his or her experience (Rotter, 1966). The ex
tent of control individuals believe they have
over their environment (LOC) can influence
perceived stress levels, such that a greater
perception of control is related to lower per
ceived stress (Anderson, 1977; Hellhammer,
Wust, & Kudielka, 2009; Roddenberry &
Renk, 2010). While perceived stress and
physiological stress may be positively cor
related, they are not extensions of one another
per se (van Eck, Berkhof, Nicolson, & Su-
lon, 1996). Physiological stress is a result of
nearly automatic cognitive and emotional ap
praisals of stimuli and perceived stress incor
porates the individual’s perceptions of their
ability to handle the situation. This indicates
that LOC may not be associated with physio
logical stress in the same pattern as it is with
perceived stress. However, few studies have
looked at LOC following the direct manipu
lation of stress. Therefore, further research is
needed to determine whether perceptions of
control can moderate the physiological acute
stress response.
The acute stress response is located within
the body’s corticotrophin-releasing hormone
system. Responses to events deemed danger
ous or exciting begin with the activation of
paraventricular corticotropin-releasing factor
and arginine vasopressin neurons in the para
ventricular nucleus ofthe hypothalamus (Hell-
hammer, Wust, & Kudielka, 2009; O’Connor,
O’Halloran, & Shanahan, 2000). Corticotro
pin-releasing hormone then stimulates the
release of adrenocorticotrophic hormone
(ACTH; O’Connor et al., 2000). ACTH stim
ulates the release of cortisol, a glucocorticoid
from the adrenal glands, activating the fight-
or-flight response, which includes increased
heart rate, suppressed immune function, and
inhibited digestion. Under normal transient
stress conditions, cortisol helps to successfully
defend against a threat, and then is terminated
by initiating a negative feedback mechanism
to inhibit the hypothalamus’s corticotro
pin-releasing factor production (Sapolsky,
1994). Cortisol has been demonstrated to be
a reliable index of the hypothalamic pituitary
adrenal (HPA) chemical cascade, and it is a
common biomarker for stress (Hellhammer
et al., 2009). For this reason, the HPA axis
and cortisol have been a focal point of recent
stress research. Particular emphasis has been
on factors that may be associated with blunted
or heightened stress responses.

Cortisol Reactivity and Speech Performance in Response to Acute Stress / 227
Few studies have examined LOC and cor
tisol reactivity in acute stress contexts. The
scant available literature on LOC and phys
iological responses to stress is both limited
and mixed. For example, some studies have
demonstrated that a more internal LOC is
associated with reduced physiological activa
tion (Pruessner, Hellhammer, & Kirschbaum,
1999; Pruessner et al., 2005), and yet others
found no association between LOC and phys
iological activation (Bollini, Walkter, Ha-
mann, & Kestler, 2004; Pruessner et al., 1997).
Flowever, varying methodologies seem to be
confusing the state of the literature. For exam
ple, one study employed a cold-water stressor
(Viena, Banks, Barbu, Schulman, & Tartar,
2012); another used computer tasks thought
to induce a stress response (Pruessneret al.,
1999) and still others used a combined speech
and mental arithmetic psychosocial task
(Pruessner et al., 1997). While the first two
are well controlled laboratory measures, they
lack generalizability outside of the lab envi
ronment. For applicability, a psychosocial
stressor may have more ecological validity.
Measures of cortisol have also been variable,
one study used area under the curve cortisol
over the length of the session (Pruessner
et al., 1997; Pruessner et al., 2005), others
correlated LOC with absolute cortisol output
post-stressor (Viena et al., 2012) and others
used change scores for the difference pre- and
post-task (Bollini et al., 2004). Use of post
task values could be a large limitation due
to individual differences in baselines. Delta
cortisol values (i.e., post-talk minus baseline)
may prove to be more informative to make
comparisons across individuals or groups.
While most studies used undergraduate stu
dent samples, another variation has been the
gender representation, with a subsample of
studies focusing on male participants (Pruess
ner et al., 1997). Importantly, measures of
LOC have also differed. Across six studies
of LOC and acute stress, four measures of
LOC were utilized. Differences in the con
struct measure may influence outcomes and
conclusions. For example, some studies used
the Questionnaire of Competence and Con
trol, a combined measure of self-esteem and
LOC (Pruessner et al., 1997; Pruessner et
al., 1999; Pruessner et al., 2005). However,
when studies have looked at the constructs of
perceived control separate from self-esteem
(e.g. Scarpa & Luscher, 2002), greater base
line perceptions of control, or less helpless
ness, predicted post-task change in cortisol,
but this was not a validated measure of LOC.
Variations in the construct measured may
contribute to the diverse findings. Finally,
some of these studies examined performance
independently in the context of acute stress,
but few have examined the moderating role
LOC may play. Overall, regardless of condi
tion, greater self-esteem and a more internal
LOC on the LOC/self-esteem measure were
associated with better performance (e.g.
Pruessner et al., 1999). Still, the relationship
between LOC and cortisol is mixed. This
may be due to the breadth of stressors that
have been employed. In sum, the general
izability of the results may be a function of
the way in which the research questions have
been assessed.
Past research has suggested a relationship
between LOC and performance in a wide
range of disciplines, such that a more inter
nal LOC is associated with better workplace
and public speaking performance (Bemardi,
2011; Judge & Bono, 2001; Spector, 1986).
For example, in a meta-analysis on four
self-evaluation characteristics, job satisfac
tion, and performance, a more internal LOC
was associated with higher job performance
(Judge & Bono, 2001). In college students
with new jobs, a more internal LOC was
associated with perceiving stress as positive
and resulted in higher achievement in their
work role (Bemardi, 2011). A meta-analysis
on employee perceptions of control found

that greater perceived control, comparable
to an internal LOC, was related to greater
motivation and performance, as well as lower
self-reported physical and emotional distress
(Spector, 1986). In terms of public speaking,
a more internal LOC is associated with less
self-reported anxiety about communicating
with others, and a more external LOC is as
sociated with less goal-directed speech and
less motivation in communicating (Rubin,
1993). An internal LOC appears to provide
a benefit for performance in a variety of set
tings; however, this body of research has not
examined the role of physiological stress in
these relationships.
One study examined the relationship be
tween LOC and performance under varying
levels ofstress to determine ifboth internals and
externals follow the Yerkes-Dodson hypoth
esis of performance, where arousal increases
performance for low levels of arousal and
then negatively impacts performance at high
levels of arousal (Guar & Upadhyay, 1988).
Overall, performance increased over the stress
levels, peaking at moderate stress, consistent
with the Yerkes-Dodson hypothesis. There was
a significant interaction between stress and
LOC, divided into external and internal using
a median split, such that under severe stress,
internals maintained the high performance but
externals performed significantly worse. While
this article is dated, it is one of the first that
looked at the three factors (LOC, stress and
performance) in an a priori design to examine
respective relationships.
Present Study
In order to better understand the relation
ship between LOC, performance and cortisol,
the present study evaluated these associations
following an experimentally-induced, acute
stress paradigm. In this process, we observed
the relationship of perceived control with the
biological stress response and performance
on a public speaking task. This builds on
past research by addressing several of the
methodological limitations identified above.
Specifically, this study used Rotter’s LOC
scale, a frequently employed measure of in
ternal or external LOC across a wide range of
domains, including psychotherapy outcomes
and academic or occupational achievement
(Baker, 1979; Parker, 2003). We also used
an empirically-supported paradigm to induce
psychosocial stress, the Trier Social Stress
Test (TSST; Kirschbaum, Pirke, & Hellham-
mer, 1993). The TSST includes both a public
speaking and mental arithmetic component
and has been demonstrated to induce a robust
physiological response (Kirschbaum et al.,
1993). Past research has examined perceived
stress, which is not always representative of
physiological activation (van Eck et al., 1996).
Other research examined students during
mid-term examination time, which introduces
variables of preparedness and additional in
dividual differences that may confound find
ings (Viena et al., 2012). Manipulating stress
experimentally allows for the examination of
factors that may influence the HPA response
to acute stress. Another benefit of using the
TSST is that every participant is introduced
to the same stimulus, an acute stressor, in a
controlled environment.
While both the public speaking and math
portion have a synergistic effect in making the
TSST a reliable stressor, public speaking has
a more ecologically-valid role. Public speak
ing is widely reported to be one of the biggest
fears, one that causes tremendous amounts of
stress for people (Richmond & McCroskey,
1995). Conversely, verbal communication
skills are also ranked as the most desirable
characteristic for employers (National As
sociation of College and Employers, 2011),
indicating a need to better understand the fac
tors influencing effective communication and
what may mediate apprehension and anxiety.
One such factor may be LOC. Furthermore,
to our knowledge, no previous study has

experimentally manipulated stress and exam
ined the role LOC has on speech performance
under stress. Therefore, the present study
considered potential associations between
LOC and performance following stress with
the purpose of examining potential interplay
between this perception and the biological
stress system. Another goal is to establish the
relationship between perceptions of control
and actual performance under demanding and
unexpected circumstances. In sum, the pres
ent study seeks to further clarify relationships
of LOC on HPA functioning and speech per
formance in response to acute stress.
Hypotheses
The present study examines the relation
ships between LOC and both cortisol reac
tivity and speech performance in response to
acute stress. The primary hypothesis is that
there would be an inverse relationship with an
internal LOC and cortisol reactivity, whereby
a more internal LOC would predict a lesser
degree of reactivity to the laboratory stressor.
Our secondary hypothesis is that there will be
a negative linear relationship between LOC
and speech performance, such that a more
internal LOC would predict better speech per
formance. Third, we examined whether stress
differentially affects speech performance
based on one’s LOC. We hypothesize that
those with a more internal LOC will perform
better on the public speaking task despite the
relative increase in cortisol.
Methods
Participants
One-hundred thirteen undergraduate stu
dents were recruited from psychology courses
at a metropolitan university. To be eligible
for the study, participants had to be at least
18 years of age and currently enrolled in an
undergraduate psychology course. Exclusion
criteria included presence of a neuroendo
crine disorder, history of a psychological
disorder in the six months prior to the study,
and currently taking psychoactive medica
tions. The sample was 75.2% female and ages
ranged from 18-41 (M= 19.79,50 = 3.05). In
addition, participants were ethnically diverse
(22% Caucasian, 4.4% African American,
22% Latino/Latina, 31% Asian, 17% other
and 1.8% N/A).
All participants provided informed con
sent and received course credit for participa
tion. The study protocol was approved by the
local Institutional Review Board.
Measures
Screening and Demographics. Prior to
the start of each research session, participants
completed a briefscreening questionnaire that
asked about activities in the last hour. This
was to ensure compliance with the pre-visit
restrictions of not eating, drinking, smoking
or exercising. It also evaluated whether the
participant met eligibility criteria of not hav
ing a neuroendocrine disorder, not currently
taking psychoactive medications, and not
presenting with a psychological disorder in
the past six months. Participants who did not
meet eligibility criteria were not allowed to
participate and those that violated pre-visit
restrictions were rescheduled. Participants
also completed a basic demographic form that
inquired about age, gender, ethnicity, major,
year in school, GPA, and English proficiency.
Locus of Control. To assess LOC, par
ticipants completed a 29-item self-report
questionnaire, of which only 23 were scored
(Rotter, 1966). The other six questions are
filler questions. For each item, the participant
was presented with two statements, one rep
resenting internal LOC and one representing
external LOC. Instructions stated there was no
right or wrong answer but to choose the state
ment that the individual agrees with most. En
dorsing the external statement earned a score
of a 1. Responses were summed to create a
total score that ranged from 0-23, where lower

scores indicate an internal LOC and higher
scores indicate a more external LOC. The
range for this sample was 5-19. Cronbach’s al
pha for Rotter’s LOC scale has been reported
to be between .65 and .80 (Lange & Tiggle-
man, 1981; Rotter, 1966). Test-retest reliabili
ty over a two-year period has been reported to
be .61 in a sample ofAustralian undergraduate
students (Lange & Tiggleman, 1981).
Acute Stress Manipulation. The TSST
takes approximately 15 minutes and involves
both a speech and math task (Kirschbaum et
al., 1993). First, experimenters led partici
pants into a room with a table that had a video
camera and two judges. The room was kept
regulated (e.g. temperature and light) and was
free of decor. Participants prepared for the
speech for three minutes in a different room
and were instmcted that they would not be
able to use their notes during the speech. At
the end of three minutes, participants were
asked to stand behind a line placed between
the wall and the camera and gave a five min
ute speech in which they were instructed to
“state your ideal job and convince the com
mittee why you are the best candidate for the
job.” If participants paused for longer than
20 seconds, they were prompted by the main
judge with “You still have more time, please
continue.” Following the speech, participants
completed a five minute mental arithmetic
task counting aloud backwards from 2083
subtracting by 13 each time. These tasks were
completed in the presence of two judges that
were instmcted to maintain emotionless and
only speak using scripted statements.
Speech Performance. As part of the
TSST, each speech was recorded and evaluat
ed by a team of two judges on a scale of 8-40.
A 5 point Likert Scale (1 = Poor, 5 = Great)
was used for each of eight characteristics of
performance (Organization, Persuasiveness,
Content, Clarity, Volume, Speed, Profes
sionalism, and Friendliness). Examples of
criteria assessed are maintaining eye contact,
consistently making friendly expressions
such as smiles or gestures (friendliness), and
keeping a constant pace of speech (speed).
These characteristics were based on criteria
suggested in studies of job interview perfor
mance and forms for evaluating interview
performance (Hollandsworth, Kazelskis, Ste
vens & Dressel, 1979; McCarthy & Goffin,
2004). Inter-rater reliability was computed to
be Cohen’s k = >.90.
Cortisol Reactivity. Participants gave
four saliva samples during the study to assess
salivary cortisol. The experimenter instmcted
the participant to chew for one minute on cot
ton swabs that were placed inside Salivette®
tubes with cotton swabs (Sarstedt AG & Co.,
Numbrecht, Germany). To ensure compli
ance, the experimenter remained in the room
during the minute but turned away as the
participant returned the cotton cylinder to the
tube without using their hands. The samples
were kept at 5 °C until analysis with ELISA
assays with Expanded Range High Sensitiv
ity Salivary Cortisol Enzyme Immunoassay
Kit (Salimeterics LLC, State College, PA).
All samples were analyzed in duplicate for
reliability purposes. The first sample was con
sidered the baseline sample and peak cortisol
was the larger of the two samples given at 10
and 20 minutes post-task.
Procedure
Participants completed the experiment
individually. All experiments were conducted
between 12 and 6 pm to account for circadian
rhythm cycles of cortisol (Kudielka, Schom-
mer, Hellhammer, & Kirschbaum, 2004). The
study began with informed consent and with
an introduction phase where the experiment
ers clarified any questions about procedure
and anonymity. Participants then gave their
first baseline saliva sample and completed
an eight minute neutral task which was part
of a larger study, the results of which are not
discussed in this paper.

All participants were then randomly as
signed at a 2:1 ratio to either the stress or con
trol condition, respectively. Those in the stress
condition completed the TSST. Participants in
the control condition watched a neutral travel
video for 15 minutes in lieu of the TSST. All
other procedures were identical for each con
dition. After completing their assigned task,
participants completed another neutral task
that took approximately ten minutes. Saliva
samples were collected before and after the
task at ten minute intervals. Participants then
had a 20 minute resting phase where they
completed several questionnaires, including
Rotter’s LOC scale and demographic informa
tion. Other questionnaires collected were part
of a larger study and included a questionnaire
on fitness and exercise, sleep habits and coping
skills. After the resting phase, participants gave
a final saliva sample and were debriefed.
Results
This study examined the relationships be
tween LOC, speech performance and cortisol
reactivity in a sample of undergraduate stu
dents at a metropolitan university. Of the 113
participants, 7 participants were removed for
missing cortisol values, 4 were removed for
having cortisol responses greater than 3 stan
dard deviations from than the mean and 3 were
removed for not completing the LOC ques
tionnaire. This left a sample of 99 participants
for data analyses: 65 in the stress condition
and 34 in the control condition. Subjects who
were removed from analyses did not differ in
age (t —.649, p > .05) or ethnicity (j2 = 5.63,
p > .05). They were, however, more likely to
be in the experimental condition compared to
the control condition (yl = 4.3,p = .04).
Gender has been shown to have a signifi
cant main effect on cortisol responses to the
TSST (Kirschbaum et al., 1993), so gender
was added as covariate predictor to models
with cortisol variables a priori.
Delta cortisol was log transformed to re
duce positive skewness, all other variables
met assumptions for normality. All means and
standard deviations presented are untrans
formed. The criterion of significance was .05.
Manipulation Check
To assess the effectiveness of the TSST
at inducing psychosocial stress, a univar
iate analysis of covariance (ANCOVA)
was conducted comparing delta cortisol in
nmol/L (Peak-Baseline) between the stress
(M= 2.26, SD = 3.82) and control (A^-.19,
«S!D=1.00) conditions. Gender was added as a
covariate. This analysis showed a significant
main effect of manipulation, F (1,98) = 7.37,
p < .01, partial eta-squared = .071. Gender
as a covariate did not reach significance, F
(1, 98) = 2.51,/? =.12. This demonstrates the
TSST was successful in producing a physi
ological response in those who completed it
compared to those in the control group.
Hypothesis 1: LOC and Cortisol Reactivity to
Acute Stress
To test the hypothesis that LOC would
significantly predict cortisol reactivity to an
acute stressor, a multiple hierarchal regres
sion was performed for the experimental
condition. In the first step, gender accounted
for 7.8% of the variance in delta cortisol, F
(1, 63) = 5.29, p = .025. Gender was a sta
tistically significant individual predictor of
delta cortisol, b = -2.51,/? = 025. When LOC
was included in the second step, the model ac
counted for 16.4% of the variance in cortisol
reactivity, F (2, 62) = 6.06,/? = .004. LOC was
a significant individual predictor, b = .340,/? =
.014, such that a more external LOC predicted
higher increases in cortisol to the acute stress
or. Gender remained a statistically significant
individual predictor, b = -2.521, p = .019,
such that males demonstrated higher cortisol
reactivity. Table 1 shows the full multiple re
gression model.

Table 1 Hierarchical Multiple Regression
Predicting Cortisolfrom LOC
b SEB P
Step 1(R2= . 078)
Gender -2.51 1.09 -.278*
Step 2 (AR2= .086)
Gender -2.52 1.05 -.280*
LOC .340 .135 .293*
Note: Total Model R^.164, *■=p < .05
Hypothesis 2: LOC predicting Speech
Performance
To test the hypothesis that LOC would
significantly predict performance on the
speech of the TSST, a simple regression was
performed. The model was significant and ex
plained 6.1% of the variance in speech perfor
mance, F (1, 62) = 4.04, p = .049. LOC was
a significant individual predictor of speech
performance, b = -.434, p = .049, such that
a more internal LOC predicted better perfor
mance on the speech portion of the TSST.
Hypothesis 3: Moderation o fLOC in predict
ing speech performance
Due to LOC’s association with both delta
cortisol and speech performance, a moder
ation model was used to test whether LOC
moderated the effect of cortisol responses on
performance. LOC and delta cortisol reactiv
ity were added in the together into the first
step of a multiple regression model. The over
all model predicted 9.0% of the variance in
speech performance, but was marginally sig
nificant, F (2, 61) = 3.021,/? = .056. LOC was
a significant individual predictor, b = -.51, p
=.02, but cortisol reactivity was not, b =.28,
p= .l. In the second step, a LOC and cortisol
interaction term was added to the model. The
overall model predicted 12% of the variance
in speech performance but was only marginal
ly significant, F (3, 60) = 2.74, p = .051. LOC
remained a statistically significant predictor,
b= -.65, p = .009. Neither delta cortisol nor
the LOC by cortisol interaction term predicted
speech performance. This regression model is
shown in Table 2.
Table 2 Hierarchical Multiple Regression
Predicting Speech Performance
b SEB P
Step 1(R2= .090)
Delta Cortisol .275 .197 .176
LOC -.511 .221 -.291*
Step 2 (AR2= .03)
Delta Cortisol -.902 .842 -.577
LOC -.650 .240 -.370**
Delta Cortisol X LOC .090 .063 .795
Note: Total Model R ^ . 120, *=p < .05, ** =p<.01
Discussion
This research sought to determine how
perceptions of control affected biological
reactions to acute stress and how those per
ceptions affected subsequent speech perfor
mance. Several key findings emerged from
our investigations. First, LOC predicted
cortisol reactivity to a laboratory stressor.
Participants with a more external LOC re
sponded with higher cortisol responses to the
TSST, supporting our first hypothesis. This
indicates that if subjects view themselves as
not having control over their environment,
they are more likely to demonstrate a greater
physiological response to an experimental
paradigm. Our findings are in contrast with
some prior research. For example, Bollini
and colleagues (2004) concluded that corti
sol did not differ based on LOC orientation
after using a noise stressor. This inconsistent
finding may be due to differences in reactions
to stressors utilized, the evaluative piece
present in the TSST or the measure of LOC
used. Conversely, our findings are consistent
with research by Lundberg and Frankenhae-
user (1978), who concluded that individual

differences in subjective and physiological
responses to stress (e.g. cardiovascular, adre
nal medullary, and adrenocortical reactions)
are influenced by the extent to which the in
dividual feels events are outside their ability
to control them.
Second, LOC negatively predicted speech
performance, such that a more internal LOC
predicted better performance on a public
speaking task, supporting our second hypoth
esis. While, to the best of our knowledge, this
is the first study to examine speech perfor
mance and LOC, this is consistent with some
what similar studies done with introductory
college students. One study demonstrated
those with an internal LOC were more likely
to use facilitating anxiety and this relation
ship decreased as LOC became more exter
nal (Butterfield, 1964). The author described
facilitating anxiety as highly adaptive and
motivating in a stressful situation compared
to debilitative anxiety, which is more mal
adaptive in that it limits success in a stressful
situation, consistent with the Yerkes Dodson
hypothesis of arousal. Similarly, students
with a more external LOC showed higher test
anxiety compared to those with an internal
LOC, however, exam performance was not
measured (Choi, 1998). In a study that used
a mental arithmetic stressor (Walsh, Wilding
& Eysenck, 1994), those with an internal
LOC had a higher probability of giving a
correct answer than those with an external
LOC. Rotter (1966) also hypothesized that
those with a more internal LOC would have a
greater ability to control how they performed
in certain environments, while those with an
external LOC would exhibit greater difficulty
maintaining performance.
Third, to confirm that LOC’s relation
ship to cortisol did not drive the subsequent
relationship between LOC and speech per
formance, a multiple regression was run
predicting speech performance from both
LOC and cortisol. The overall model was
only marginally significant; this may be
due to low power (post hoc power analysis
= .66) from three predictors or, perhaps,
shared variance between delta cortisol and
LOC. However, despite this, LOC predict
ed speech performance and this was not
attenuated by cortisol. This demonstrates
that LOC predicts speech performance in
dependent of increased cortisol and should
be investigated in larger samples.
Limitations
There were a few limitations that should
be addressed. First, this was a convenience
sample taken from college students enrolled
in an introductory psychology course. Addi
tionally, this sample was primarily female,
which is representative of the ratio of males
to females in the psychology department at
the university. Both factors limit our ability
to generalize the findings outside of this pop
ulation. Future research should recruit more
male participants in order to better examine
these relationships and examine community
populations. Males had significantly higher
reactivity to the laboratory stressor in the
final model. While some research has shown
gender differences are due to estrus cycle
variations (e.g. Kirschbaum et al., 1999),
our lab has not replicated menstrual cycle or
oral contraceptive gender differences, so our
analyses controlled for gender and did not
stratify by gender.
Additionally, our measure of speech
performance, while formatted on empirical
work, was created within our lab. Future
research could be done assessing these
criteria and could explore other areas of
performance. It is worthy to note that the
criteria assessed are consistent with recent
descriptions highlighting the importance of
examining variables such as content, and
voice quality as well as eye contact and fa
cial expressions (Scherer & Volk, 2011).

Broader Implications & Future Directions
To our knowledge, this research was the
first to examine LOC, speech performance
and cortisol reactivity using a laboratory
stressor paradigm. We were able to demon
strate that cortisol did not account for the
relationship between LOC and speech per
formance, indicating that LOC is an inde
pendent predictor for both cortisol reactivity
and speech performance. In summary, this
body of research demonstrates that LOC
predicts both cortisol reactivity to an experi
mental stressor and performance on a public
speaking task in a racially diverse sample of
undergraduate participants.
This research adds to a growing body of
literature that demonstrates functional dif
ferences between those with an internal LOC
and those with a more external LOC. In terms
of mental health, some research has shown a
more internal locus of control to be associat
ed with lower depression (e.g. Gray-Stanley
et al., 2010), though unrelated to anxiety
(Wamecke, Baum, Peer, & Goreczny, 2014).
While LOC’s stability as a personality
characteristic is largely accepted, Legerski,
Cornwall, and O’Neil (2006) determined that
LOC is not stable, such that an internal LOC
can become more external. In this study, the
authors concluded this happened in reac
tion to layoffs in a steel working plant and
were a reflection of the real constraints and
opportunities an individual experiences in
chronic unemployment or underemployment
situations. Further, psychotherapy research
has shown that LOC can be malleable and
changes toward a more internal LOC over
the course of therapy (Baker, 1979). Future
research should examine whether one can
manipulate perceptions of control, perhaps
by priming an internal LOC to determine
whether this develops resistance to mood
and physiological reactivity. Further, chron
ic and acute stress often interact to predict
disease (e.g. McEwen & Stellar, 1993) so the
impact of LOC on chronic stress may also be
an important area to consider.
Further, performance in a public speaking
paradigm is ecologically valid, but this is not
the sole area of performance that could be
experimentally examined. Tasks that focus
on executive functioning, the ability to apply
past experience to future activity, or working
memory may provide additional insight into
areas of performance influenced by LOC.
Both of these domains (memory and execu
tive functioning) have been shown to be in
fluenced by stress (e.g. Holmes & Wellman,
2009) and may be a promising area of future
research. The present study focused on corti
sol due to associations with memory, mental
health vulnerability and hippocampal volume
(e.g. Dickelmann, Wilhelm, Wagner, & Bom,
2011; Frodl & O’Keane, 2013; Stetler & Mill
er, 2011). However, other markers of stress
physiological may also be examined.
LOC is an orientation that primes how in
dividuals view the environment and their role
in situations. LOC may have diverse implica
tions for success in clinical, occupational and
academic settings and merits future research
for the extent that they can be explored and
manipulated.
Acknowledgements
This research was conducted within the
Psychology department of San Jose State
University as a part of the work of the Inter
national Neuroeconomics Institute (INI) lab.
This was partially made possible through a
grant from the National Institute of General
Medical Sciences (#5T34GM008253-23) to
the MARC program at San Jose State Univer
sity. Additionally, we wish to acknowledge
the members of the INI lab at San Jose State
University for their help in data collection.

References
Anderson, C. R. (1977). Locus of control, coping behav
iors, and performance in a stress setting: a longitu
dinal study. Journal o f Applied Psychology, 62(4),
446^151.
Baker, E. K. (1979). The relationship between locus of
control and psychotherapy: Areview ofthe literature.
Psychotherapy: Theory, Research & Practice, 16(3),
351-362.
Bcmardi, R. A. (2011). The relationships among locus of
control, perceptions of stress and performance. Jour
nal ofAppliedBusiness Research, 13(4), 1-8.
Bollini, A. M., Walker, E. F., Hamann, S., & Kestlcr, L.
(2004). The influence of perceived control and locus
of control on the cortisol and subjective responses to
stress. Biological Psychology, 67(3), 245-260.
Butterfield, E.C (1964). Locus of control, test anxiety,
reactions to frustration and achievement attitudes.
Journal o fPersonality, 32(3), 355-370.
Choi, N. (1998). The effects of test format and locus of
control on test anxiety, Journal of College Student
Development, 39(6), 616-620.
Diekelmann, S., Wilhelm, L, Wagner, U., & Bom, J.
(2011). Elevated cortisol at retrieval suppresses false
memories in parallel with correct memories. Journal
ofCognitive Neuroscience, 23(4), 772-781.
Frodl, T., & O’Keanc, V. (2013). How does the brain
deal with cumulative stress? A review with focus
on developmental stress, FIPA axis function and
hippocampal structure in humans. Neurobiology of
Disease, 52, 24-31.
Gray-Stanley, J. A., Muramatsu, N., Heller, T., Hughes,
S., Johnson, T. P., & Ramirez-Valles, J. (2010). Work
stress and depression among direct support profes
sionals: the role ofwork support and locus ofcontrol.
Journal of Intellectual Disability Research, 54(8),
749-761.
Guar, S.D. & Upadhyay, H.S. (1988). Performance as
a function of stress and locus of control, Journal of
Personality <6 Clinical Studies, 4(1), 85-88.
Hellhammer, D. K., Wust, S. & Kudielka, B.M. (2009).
Salivary cortisol as a biomarker in stress research,
Psychoneuroendocrinology, 34, 163-171.
Hollandsworth, J.G., Kazclskis, R., Stevens, J. & Dressel,
M.E. (1979). Relative contributions ofverbal, articu-
lative, and nonverbal communication to employment
decisions in the job interview setting, Personnel
Psychology, 32(2), 359-367.
Holmes, A., & Wellman, C. L. (2009). Stress-induced
prefrontal reorganization and executive dysfunction
in rodents. Neuroscience & Biobehavioral Reviews,
33(6), 773-783.
Judge, T. A., & Bono, J. E. (2001). Relationship of core
self-evaluations traits—self-esteem, generalized
self-efficacy, locus of control, and emotional stabil
ity—with job satisfaction and job performance: A
meta-analysis. Journal ofAppliedPsychology, 56(1),
80-92.
Kirschbaum, C., Kudielka, B. M., Gaab, J., Schommer,
N. C., & Hellhammer, D. H. (1999). Impact of gen
der, menstrual cycle phase, and oral contraceptives
on the activity ofthe hypothalamus-pituitary-adrenal
axis. Psychosomatic Medicine, 61(2), 154-162.
Kirschbaum, C., Pirke, K., & Hellhammer, D. H. (1993).
The ‘trier social stress test’:A tool for investigating
psychobiological stress responses in a laboratory set
ting. Neuropsychobiology,28(1-2), 76-81.
Kudielka, B.M., Schommer, N.C., Hellhammer, D.H., &
Kirschbaum, C. (2004) Acute HPA axis responses,
heart rate, and mood changes to psychosocial stress
(TSST) in humans at different times of day, Psycho
neuroendocrinology,29, 983-992
Lange, R.V. & Tiggleman, M. (1981). Dimensionality
and reliability ofthe Rotter I-E locus of control scale.
Journal ofPersonality Assessment, 45(4), 398^406.
Legerski, E. M., Cornwall, M., & O’Neil, B. (2006).
Changing locus of control: Steelworkers adjusting
to forced unemployment. Social Forces, 84(3),
1521-1537.
Lundberg, U. & Frankcnhacuscr, M. (1978). Psychophys-
iological reactions to noise as modified by personal
control over noise intensity, Biological Psychology,
6, 51-59.
McCarthy, J. & Goffin, R. (2004). Measuring job inter
view anxiety: Beyond weak knees and sweaty palms,
Personnel Psychology, 57(3), 607-637.
McEwen, B. S., & Stellar, E. (1993). Stress and the indi
vidual: mechanisms leading to disease. Archives of
Internal Medicine, 753(18), 2093-2101.
National Association of Colleges and Employers. Job
Outlook Survey 2011, retrieved from http://www.
naceweb.org/Research/Job Outlook/Job Outlook,
aspx
O’Connor, T.M., O’Halloran, D.J., & Shanahan, F.
(2000). The stress response and the hypothalamic-pi
tuitary-adrenal axis: from molecule to melancholia,
Quarterly Journal o fMedicine, 93, 323-333.
Parker, A. (2003). Identifying predictors of academic
persistence in distance education. Usdla Journal,
77(1), 55-62.
Pruessner, J. C., Baldwin, M. W., Dedovic, K., Renwick,
R-, Mahani, N. K., Lord, C., Meaney, M. & Lupien,
S. (2005). Self-esteem, locus of control, hippocam
pal volume, and cortisol regulation in young and old
adulthood. Neuroimage, 28(4), 815-826.

Pruessner, J.C., Gaab, J., Hellhammer, D.H., Lintz, D.,
Schommer, N., & Kirschbaum, C. (1997), Psycho-
neuroendocinology, 22(8), 615-625.
Pruessner, J.C., Hellhammer, D.H., & Kirschbaum, C.
(1999). Low self-esteem, induced failure, and the
adrenocortical stress response. Personality and Indi
vidualDifferences, 27,477-489.
Richmond, V.P., & McCroskey, J.C. (1995). Communi
cation: Apprehension, avoidance, and effectiveness
(4th ed.). Scottsdale, AZ: Gorsuch Scarisbrick.
Roddenberry, A., & Rcnk, K. (2010). Locus of control
and self-efficacy: potential mediators of stress,
illness, and utilization of health services in college
students. Child Psychiatry & Human Development,
41(4), 353-370.
Rotter, J. B. (1966). Generalized expectancies for internal
versus external control of reinforcement. Psycholog
ical monographs: General and applied, 50(1), 1-27.
Rubin, A. M. (1993). The effect of locus of control on
communication motivation, anxiety, and satisfaction.
Communication Quarterly, 41(2), 161-171.
Sapolsky RM. 1994. Why Zebras Don't Get Ulcers: A
Guide to Stress, Stress-Related Diseases, and Cop
ing. New York: W.H. Freeman.
Scarpa, A., & Luscher, K. A. (2002). Self-esteem, cor
tisol reactivity, and depressed mood mediated by
perceptions ofcontrol. Biological Psychology, 59(2),
93-103.
Scherer, R. C., & Volk, M. (2011). Research on public
speaking. Voice and Speech Review, 7(1), 287-291.
Spcctor, P.E. (1986). Perceived control by Employees:
A Meta-Analysis of Studies concerning Autonomy
and Participation at Work, Human Relations, 39(11),
1005-1016.
Stetler, C., & Miller, G. E. (2011). Depression and hypo-
thalamic-pituitary-adrenal activation: a quantitative
summary offour decades ofresearch. Psychosomatic
Medicine, 73(2), 114-126.
Viena, T.D., Banks, J.B., Barbu, I.M, Schulman, A.H.,
& Tartar, J.L (2012), Differential effects of a mild
chronic stress on cortisol and S-IgA responses to
an acute stressor, Biological Psychology, 91(2),
307-311.
Van Eck, M., Berkhof, H., Nicolson, N., & Sulon, J.
(1996). The effects of perceived stress, traits, mood
states, and stressful daily events on salivary cortisol,
Psychosomatic Medicine, 58, 447-458.
Walsh, J.J., Wilding, J.M., & Eysenck, M.W. (1994).
Stress responsivity: The role of individual differ
ences. Personality Individual Differences, 16(3),
385-394.
Wamcckc, A. J., Baum, C. A., Peer, J. R., & Goreczny,
A. J. (2014). Intercorrelations between Individual
Personality Factors and Anxiety. College Student
Journal, 45(1), 23-33.

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