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How to Improve Adolescent Stress Responses:
Insights from an Integration of Implicit Theories and Biopsychosocial Models
David S. Yeager
Hae Yeon Lee
University of Texas at Austin
Jeremy Jamieson
University of Rochester
April, 2016
In press at Psychological Science
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Abstract
This research integrated implicit theories and the biopsychosocial (BPS) model of challenge and
threat, hypothesizing that adolescents would be more likely to conclude that they have the
resources to meet the demands of an evaluative social situation when they were taught a belief
that people have the potential to change their socially-relevant traits. Study 1 (N=60) randomly
assigned high school adolescents to an incremental theory of personality or control condition,
and then administered a standardized social stress task. Relative to controls, incremental theory
participants exhibited improved stress appraisals, more adaptive neuroendocrine and
cardiovascular responses (lower salivary cortisol, reduced vascular resistance, higher stroke
volume, and more rapid return to homeostasis after stress offset), and better performance
outcomes. Study 2 (N=205) used a daily diary intervention study to test high school adolescents’
stress reactivity outside the laboratory. Threat appraisals (days 5-9 post-intervention) and
neuroendocrine responses (cortisol and DHEA-S; days 8-9 post-intervention only) were
untethered from the intensity of daily stressors when adolescents received the incremental theory
of personality intervention. The intervention also improved grades over freshman year. These
findings offer new avenues for improving theories of adolescent stress and coping.
Keywords: biopsychosocial model, implicit theories of personality, stress, biological
psychology, social-evaluative threat, adolescence.
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How to Improve Adolescent Stress Responses:
Insights from an Integration of Implicit Theories and Biopsychosocial Models
Negative social evaluations are ubiquitous during adolescence (Crosnoe, 2011). Such
stressors can contribute to dysregulations in neuroendocrine and autonomic reactivity that can
accumulate into mental and physical health problems, impaired cognitive performance, and even
academic underachievement (Crosnoe, 2011; Goodyer, 2001; Gunnar, Wewerka, Frenn, Long, &
Griggs, 2009; Lopez-Duran, Kovacs, & George, 2009; Marceau, Ruttle, Shirtcliff, Essex, &
Susman, 2015; Wolkowitz, Epel, & Reus, 2001).
Here we integrate two research traditions—each of which has proceeded independently in
the literature—to advance theory regarding the causes of and improvements to adolescents’
social stress responses. These are: (1) the biopsychosocial (BPS) model of challenge and threat,
which provides a mechanistic framework for understanding social stress responses (Blascovich,
2008; Blascovich & Mendes, 2010; Jamieson, Mendes, & Nock, 2013; Seery, 2013), and (2)
implicit theories of personality (Chiu, Hong, & Dweck, 1997; Dweck, Chiu, & Hong, 1995;
Yeager & Dweck, 2012), which are beliefs that shape individuals’ interpretations of the meaning
of social stressors they face. Specifically, we examined the effects of an intervention targeting
implicit theories of personality on the cognitive, physiological, and behavioral processes well-
studied in BPS models.
Theoretical Background
A fundamental principle of the BPS model of challenge and threat is the idea that
cognitive appraisals of situational demands and coping resources interact to determine stress
responses in motivated-performance contexts (Blascovich & Mendes, 2010; Gross, 2015;
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Jamieson, Mendes, et al., 2013; Mendes & Park, 2014; Seery, 2013). When individuals perceive
that they possess sufficient resources to cope with the situational demands posed by the
stressor(s), they experience challenge. However, when situational demands are seen as
exceeding resources, individuals experience threat.
Physiologically, both challenge and threat states create greater sympathetic nervous
system activation, but they differ in the quality of that activation. Challenge states prepare the
body for approach-oriented behaviors. Challenge states increase delivery of oxygenated blood to
the brain and peripheral sites by means of greater activation of the sympathetic-adrenal-
medullary (SAM) axis, which produces vasodilation and leads to increased cardiac efficiency
(Jamieson, Valdesolo, & Peters, 2014; Mendes, Blascovich, Lickel, & Hunter, 2002).
Threat states, by contrast, prepare the body for damage or social defeat, and more
strongly activate the hypothalamus-adrenal-pituitary (HPA) axis, producing reduced cardiac
efficiency and increased vascular resistance downstream. Thus, individuals experiencing threat
are likely to exhibit increased production of cortisol—a catabolic adrenal hormone that is the
end-product of HPA-axis activation (Dickerson & Kemeny, 2004; Stroud et al., 2009; Zijlmans,
Beijers, Mack, Pruessner, & de Weerth, 2013). Moreover, threatened individuals return to
homeostasis more slowly (for instance, they show sympathetic activation even after stress
offset), as stress reactions linger (Dickerson & Kemeny, 2004; Dienstbier, 1989). This failure to
return to homeostasis contributes to poorer long-term health and cognitive performance
outcomes of chronic threat-type activation (Blascovich, 2008; McEwen, 2006).
In the context of the BPS model of challenge and threat, changing appraisals of resources
and demands has the potential to change downstream physiology, cognitions, and behavior in
stressful situations (e.g., Jamieson, Mendes, Blackstock, & Schmader, 2010; Jamieson, Mendes,
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et al., 2013; Jamieson, Nock, & Mendes, 2013). Surprisingly, experimental research has not fully
demonstrated why adolescents might appraise everyday stressful social situations as events that
they do not have the resources to cope with.
In this vein, we hypothesized that research on implicit theories of personality—which are
general belief systems about the malleability of people’s socially-relevant traits (Chiu et al.,
1997; Molden & Dweck, 2006; Yeager & Dweck, 2012)—may be informative. Research has
shown that some individuals hold more of an entity theory of personality, the belief that traits are
fixed and cannot change. This belief leads to “fixed” trait attributions of social failures (“I’m not
likable”) and others’ harmful behaviors (“He’s a bad person”; Chiu et al., 1997; Erdley, Loomis,
Cain, & Dumas-Hines, 1997).
For individuals with more of an entity theory, social threats or failures can be viewed as a
diagnosis of lasting social reality. From a BPS perspective, social evaluative situations might be
appraised as highly demanding (because one’s fixed status/reputation hang in the balance) and
judged as something that one does not have the resources to cope with (because no amount of
resources could overcome a fixed, deficient identity in the face of negative social evaluation).
Hence, we hypothesize that in an entity theory, appraisals of demands should exceed resources—
producing the experience of threat described by BPS models.
As initial support of this possibility, in past studies an entity theory of personality
predicted greater self-reported stress and anxiety following ostracism, as well as greater reports
of psychosocial stress (Yeager, Johnson, et al., 2014) and psychopathology (Miu & Yeager, 2015;
Schleider, Abel, & Weisz, 2015). Furthermore, implicit theories of personality relate to negative
self-conscious emotions such as shame (Yeager, Trzesniewski, Tirri, Nokelainen, & Dweck,
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2011), and these self-conscious emotions co-occur with threat-type physiological reactions to
social-evaluative stress (Dickerson & Kemeny, 2004).
Not all adolescents hold an entity theory, and those who do can be taught to adopt its
opposite, an incremental theory of personality. An incremental theory is the belief that people
have the potential to change. This belief prevents “fixed” trait attributions, so that negative
social-evaluative experiences (e.g., peer exclusion or victimization) are not seen as permanent.
Because in an incremental theory people are seen as malleable —both oneself and others—then
social adversity may be seen as improvable (Erdley & Dweck, 1993; Erdley et al., 1997; Yeager,
Trzesniewski, & Dweck, 2013; Yeager et al., 2011). That is, others’ negative social evaluations of
oneself may be viewed as problem to be solved, rather than a fixed part of one’s social reality.
Indeed, prior research has found that an incremental theory of personality intervention
reduced self-reported stress and anxiety following ostracism a day later (Yeager, Johnson, et al.,
2014). Furthermore, teaching adolescents about the possibility of personality change reduced
global self-reported stress (Yeager, Johnson, et al., 2014), behavioral aggression (Yeager et al.,
2013), and clinically-significant depressive symptoms (Miu & Yeager, 2015; Yeager, Johnson, et
al., 2014) at 9-month follow-up, while also improving academic performance in high school
(Yeager, Johnson, et al., 2014) (although the latter has only appeared in studies with small
sample sizes, or in small sub-groups, and therefore bears replication). However, no previous
research has examined whether implicit theories of personality relate to resource or demand
appraisals, or to threat-type cardiovascular or neuroendocrine responses to acute stressors, nor
has it shown the mechanisms for effects on performance in the midst of stress.
The Present Research
We test whether implicit theories of personality are global belief systems that create
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situation-specific appraisals that give rise to challenge versus threat responses to acute stressors,
and therefore provide a key to improving adolescent stress responses. We predicted that teaching
adolescents an incremental theory of personality—the belief that people’s personal
characteristics can be changed—would promote more challenge-type responses to social stress
(e.g. perceived resources > perceived demands; ↑ cardiac efficiency; ↓ vascular resistance; ↓
cortisol), resulting in improved cognitive functioning during stress (↑ task performance) and
more rapid recovery to homeostasis (↓ SNS activation during recovery epoch) relative to
threatened individuals. Two double-blind, randomized-controlled experiments—a laboratory
study and a daily diary field experiment—were used to investigate these predictions.
Study 1
Method
Participants. A power analysis based on an average effect size (d=.66) from similar
social-situational intervention research in laboratory settings using standardized social stress
induction paradigms led to a targeted sample of 30 participants per condition (Beltzer, Nock,
Peters, & Jamieson, 2014; Jamieson et al., 2010; Jamieson, Nock, & Mendes, 2012; Jamieson,
Nock, et al., 2013; John-Henderson, Rheinschmidt, & Mendoza-Denton, 2015). A total of N=60
high school students were recruited from the Rochester, NY area using posted flyers and study
information distributed by peers/teachers. Participants (55% female; 70% White/Caucasian, 15%
Black/African-American, 12% Asian/Asian-American, 3% other) were recruited from 9th, 10th,
and 11th grade classrooms (Mage = 15.61 years; range = 14-17). Participants were compensated
$50.
Participants were pre-screened and excluded for physician-diagnosed hypertension,
cardiac abnormalities, presence of a cardiac pacemaker, medications with hemodynamic side
8
effects, and pregnancy/nursing. Time since waking and start date of the previous menstrual cycle
(for females) were recorded and included as covariates in hormone analyses. All data exclusions
due to malfunction, lost data, or non-compliance are listed in the SOM-R (these varied across
measures, and so degrees of freedom varied).
Procedures. When adolescents arrived at the laboratory, the following noninvasive
sensors were affixed: electrocardiography (ECG), impedance cardiography (ICG), and blood
pressure (BP). Participants rested for a 5-min baseline recording and then provided a baseline
saliva sample. They were then randomly assigned to complete an incremental theory or an active
control reading and writing exercise. After the intervention, adolescents were told about the
social stress task and were given 3-min to prepare for their upcoming self-relevant speeches.
They then performed the social stress task (self-relevant speech followed by mental arithmetic).
This was followed by a recovery period (3-min) after which time participants provided a
reactivity saliva sample (timed to be ~20 min after stress onset)(Jamieson, Nock, et al., 2013).
Additional details regarding stress task instructions are provided in the SOM-R.
Intervention. An incremental theory of personality was taught using materials shown to
be effective in prior research (Miu & Yeager, 2015; Yeager, Johnson, et al., 2014; Yeager et al.,
2011; Yeager & Dweck, 2012). In past research the manipulation reliably led to changes in self-
reported implicit theories (Yeager, Johnson, et al., 2014; Yeager et al., 2011); self-reported
theories were not measured here).
The incremental theory intervention uses insights from research on persuasion and
internalization. It includes a 25-minute reading and writing exercise that teaches the idea that a)
if a person is excluded or victimized, it is not due to a fixed, personal deficiency, and b) people
who exclude or victimize you are not fixed, bad people, but instead have complicated
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motivations subject to change. The exercise presents true scientific evidence showing that people
can change, and also presents stories from older peers who endorsed this message. At the end of
the activity, participants summarize and endorse messages through a “saying is believing”
writing exercise, in which they attempt to persuade future students to hold an incremental theory
(Walton & Cohen, 2011; Wilson & Linville, 1982). Quotes from the intervention and sample
student responses are presented in the SOM-R.
The control condition paralleled the experimental condition, except it focused on a
domain unrelated to social-evaluative threat: adjusting to the physical environment of high
school (lockers, hallways, smells). It summarizes neuroscience research related to different
sensory experiences and includes stories from upperclassmen. Hence, it conveyed a positive
message and included advice from older peers, but was unrelated to beliefs about people’s traits.
Note that an entity theory manipulation was not used due to the ethical concern with teaching a
fixed belief; hence effect sizes correspond to a more conservative estimate.
Social stress task. Students performed a controlled social-evaluative stress task: a Trier
Social Stress Test (TSST, Kirschbaum, Pirke, & Hellhammer, 1993) that was age-modified for
adolescents. This included a 3-min anticipatory period (“preparation”), a 5-minute videotaped
speech about the attributes that make teens popular, delivered to two same-race, peer evaluators
(one male; one female)(“speech delivery”), and a 5-minute mental arithmetic task: Counting
backwards from 996 in steps of 7 (“mental math”). After the TSST, adolescents rested alone for
3-min to provide a measure of autonomic recovery from stress (“recovery”). Throughout the
speech and math tasks, evaluators provided neutral-negative nonverbal feedback (crossing arms,
frowning, sighing, etc.). Evaluators were very recent high school graduates working in the
researchers’ lab who were pretested to ensure they appeared to be within the age range of
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participants (14-17 years) (for similar procedures with teenagers see Jamieson & Mendes, in
press). The topic of the speech—a commentary on popular trends among teens—was selected
because the non-supportive, non-verbal feedback on one’s views about popularity can plausibly
be construed as a threat to social status.
Measures.
Appraisals. A stress appraisal questionnaire, developed to differentiate between
challenge and threat states, was administered immediately before and after the TSST. As is
common practice with research using this scale (see Beltzer et al., 2014), composites of
situational demands (e.g., “this situation is demanding”) and personal resources (e.g., “I have the
abilities to perform well”) were computed at each time point (αs > .80; see SOM-R for additional
details).
In the context of the BPS model threat states stem from a ratio of appraisals of coping
resources relative to perceived task demands. Consistent with this conceptualization, we created
a threat appraisal score by subtracting resources from demands, such that values greater than 0
corresponded to threat appraisals (demands > resources) and values less than 0 corresponded to
challenge (perceived resources meet or exceed demands). Threat appraisals were computed and
analyzed separately for pre- and post-TSST measures.
Neuroendocrine. To measure HPA activation, we assessed cortisol levels using two 1-ml
saliva samples. Baseline samples (T1) were collected upon arrival after autonomic baseline. A
post-task sample (T2) was taken following the TSST and timed to occur ~20 minutes after the
initial description of the speech/math task (i.e. stress onset). All study sessions were conducted
during the afternoon between noon and 6:00 pm when cortisol levels are at their waking nadir.
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Raw cortisol values demonstrated non-normality (Baseline skew p<.001; Post-test skew
p=.030). A ladder of powers analysis showed that the joint test of skew and kurtosis was reduced
to non-significance when a log transformation was carried out. There were no biologically
impossible values in this sample. Thus, no outliers were trimmed. For ease of interpretation, the
resulting metric was re-scaled to have the same mean and standard deviation as the raw data at
each time point.
Cardiovascular. As is standard in laboratory paradigms examining autonomic responses
to stressful social situations, physiological reactivity were computed by subtracting scores taken
during baseline from those collected during target tasks (see, Llabre, Spitzer, Saab, Ironson, &
Schneiderman, 1991); see Jamieson, Mendes, et al., 2013; Jamieson et al., 2012; Mendes et al.,
2002) for examples of this approach in social stress paradigms). Raw baseline scores were also
tested for condition differences that could interfere with reactivity analyses, and none were
found.
Analyses focused on pre-ejection period (PEP) – a measure of sympathetic activation –
and two measures that, in conjunction, allow distinction between approach-motivated challenge
and avoidance-motivated threat states: Stroke Volume (SV) and total peripheral resistance (TPR).
PEP indexes the contractile force of the heart by measuring the time from the initiation of
left ventricle contraction to aortic valve opening. Greater sympathetic activation is indicated by
shorter PEP intervals – that is, the stronger the force of the left ventricle contraction, the more
quickly blood will be ejected from the heart via the aorta. All participants regardless of condition
were expected to exhibit SNS activation in anticipation of and during the TSST, because the
social evaluative tasks presented acute demands that must be addressed. However, we
hypothesized that condition differences in PEP should manifest after stress offset. Recall that
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challenge responses to acute stress are associated with a more rapid return to homeostasis
relative to threat responses (Dienstbier, 1989). Thus, if the incremental theory intervention
promoted more challenge-type patterns of responding, individuals should exhibit less
sympathetic activation (higher PEP intervals) during the recovery epoch after the TSST. We
specifically included the recovery epoch in order to examine this arousal after stress offset.
SV is the amount of blood ejected from the heart during each beat and was calculated
using the Kubicek method. Combined with increased SNS activation, increased SV indicates
improved cardiac efficiency and is typically observed in challenge states, whereas a decrease (or
little change) in SV is suggestive of threat. Differences in SV reactivity were predicted at every
task epoch.
Note, we assessed cardiac efficiency SV rather than using the more common metric of
cardiac output (CO) [CO = SV * HR] because we predicted a Condition x Time interaction for
PEP (decreases in PEP correlate with increases in HR). If incremental theory participants exhibit
longer PEP intervals (i.e. less SNS activation) at recovery compared to controls, this can
manifest as reduced HR and impact the interpretation of CO in overall analyses. Thus, when
differences may exist in HR, it is more valid to assess cardiac efficiency with SV. In fact, SV
may be considered a more direct indicator of challenge/threat than CO because 1) HR contributes
little to the differentiation of challenge and threat, and 2) HR is affected by a complex interaction
of neural, sympathetic, parasympathetic, and endocrine processes (e.g., Blascovich, Berry
Mendes, Hunter, Lickel, & Kowai-Bell, 2001)
TPR is a measure of overall resistance in the peripheral vasculature. When threatened,
vascular resistance increases, limiting blood flow to the periphery and producing high TPR
scores. On the other hand, vasodilation (i.e., reduced TPR) accompanies challenge states so as to
13
facilitate delivery of oxygenated blood to the brain and periphery. TPR was calculated with the
following validated formula: TPR = (mean arterial pressure / CO) * 80 (Sherwood et al., 1990).
Differences in TPR were predicted at every post-baseline epoch. See the SOM-R for more detail
on all of these cardiovascular measures.
Performance. Two independent coders blind to condition assignment and hypotheses
coded video recordings of speech and mental math tasks using a coding scheme implemented
previously in the BPS literature to index affective responses and speech performance (see Beltzer
et al., 2014) Inter-rater reliability was good (r = .91). Raters provided a joint score when
necessary.
Speech performance was quantified as a composite of ratings of participants’ confidence,
use of non-verbal cues, eye contact, and subjective rating of speech quality (α = .867).
Performance on the mental math tasks was indexed using on two measures derived from the
video recordings: total number of errors made, and the lowest correct answer achieved.
Results
Appraisals. Students assigned to the incremental theory manipulation reported lower
threat appraisals compared to controls before (M=1.07, SD=1.88; Incremental M=−0.19,
SD=1.92), t(58)=2.57, P=0.012, d=0.63, 95%CI [.14, 1.18] and after, (Control M=1.47, SD=1.73;
Incremental M=−0.10, SD=1.64) the socially evaluative task, t(57)=3.55, P<0.001, d=0.84,
95%CI [.38, 1.45].
Figure 1A shows that control condition participants reported a value > 0 both before and
after the task, indicating the ratio of perceived demands exceeded perceived resources,
t(29)s>2.57, Ps<0.01. Alternatively, incremental theory participants exhibit a ratio no different
from zero, t(29)s<0.51, Ps>0.59. Here and throughout the paper, all reported means and standard
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deviations are from the raw data, all statistical tests are from covariate-adjusted models, and all
effect sizes are calculated from those statistical tests. Grade level and gender did not interact with
these or any other results and so they are not considered further.
We also analyzed the demand and resource sub-scales separately. The incremental theory
manipulation affected both: demand, t(57)=2.35, p=.022, d=0.62, 95%CI [0.09, 1.15], resources,
t(57)=3.93, p<.001, d=1.04, 95%CI [0.48, 1.59]. Although the condition effects on resources
were estimated to be nearly twice as large as the effects on demands, a Wald test from a
multivariate regression could not reject the null hypothesis that they were different, F(1,
58)=2.23, p=.14.
Fig. 1. Effects of incremental theory of personality intervention on self-reported threat
appraisals (perceived demands > perceived resources; 1A) and neuroendocrine responses
(salivary cortisol; 1B) before and after the Trier Social Stress Test in Study 1. N=60. Bars
correspond to ± 1 standard error of the mean.
-1
-0.5
0
0.5
1
1.5
2
Anticipation Post-task
Demands - Resources
Threat Appraisals
Control
Incremental theory of personality
0
5
10
15
20
25
Baseline Post-task
Nmol/l
Cortisol
Control
Incremental Theory of Personality
1A 1B
Neuroendocrine responses. Salivary cortisol showed no significant condition difference
at baseline, t < 1. We then analyzed acute cortisol reactivity (T2-T1). This analysis produced the
15
hypothesized condition effect, t(57) = 3.18, p = .002, d = .84 (95% CI for mean difference = 1.96
to 8.62). Incremental theory participants exhibited lower acute cortisol reactivity scores (M =
−.48 nmol/liter, SD = 4.45) than controls (M = 4.81 nmol/liter, SD = 7.82). See Figure 1B.
Cardiovascular responses. There were no differences between incremental theory and
control conditions in raw baseline measures, Fs < 1. Reactivity scores were then analyzed in 4
(Time: preparation vs. speech vs. mental math vs. recovery) x 2 (Condition: incremental theory
vs. control) mixed ANOVAs.
Analysis of PEP yielded the expected main effect for time, F(1,49) = 57.03, p < .001, d =
2.16, and the predicted Time × Condition interaction, F(1,49) = 6.62, p = .013, d = .74. See
Figure 2A. Simple contrasts were used to decompose the interaction based on a priori
predictions. Incremental theory participants exhibited less SNS activation (higher PEP intervals)
at recovery, after stress offset, than controls, F(1,49) = 10.41, p = .002, d = .92 (95% CI for mean
difference = -7.37 to -.93). At recovery, those in the incremental condition did not differ from
their pre-task PEP levels, F(1, 49)=0.10, p>.75, showing a more rapid return to homeostasis.
Figure 2A furthermore shows that it was not the case that those in the incremental theory
group were disengaged during the stressful task: No condition differences in sympathetic
activation were observed in anticipation of and during the stress task.
Next, analysis of SV reactivity produced the predicted main effect for condition, F(1,48)
= 11.17, p = .002, d = .95 (95% CI for the mean difference = -11.09 to -2.76). As shown in
Figure 2B, across all reactivity epochs incremental theory participants ejected more blood per
beat compared to controls.
Finally, for TPR, there emerged the hypothesized main effect such that incremental
theory participants exhibited less vascular resistance (lower TPR reactivity scores) across all
16
reactivity epochs compared to controls, F(1,46) = 12.65, p = .001, d = 1.02 (95% CI for mean
difference = 72.65 to 262.04). See Figure 2C.
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Figure 2. Effects of incremental theory of personality continuously-monitored autonomic
responses (PEP, TPR and SV) before, during and after the Trier Social Stress Test (TSST)
in Study 1. Bars correspond to ± 1 standard error of the mean.
1500
1600
1700
1800
1900
2000
2100
Baseline
Anticipation
Speech
Math
Recovery
dyne-sec x cm-5
Total Peripheral Resistance (TPR)
Control Incremental Theory of Personality
40
50
60
70
Baseline Anticipation Speech Math Recovery
ml
Stroke Volume (SV)
80
85
90
95
100
105
110
Baseline
Anticipation
Speech
Math
Recovery
ms
Pre-Ejection Period (PEP)
Control Incremental Theory of Personality
2A
2B
2C
Performance. Speech performance and lowest number achieved in the mental math task
were significantly correlated (r = -.360, p = .008), as were mental math errors and lowest number
achieved (r = .638, p < .001). To account for family-wise error, effects of condition on
performance variables were analyzed in a multivariate analysis of variance (MANOVA) model
(no covariates were included). As hypothesized, this analysis yielded a multivariate main effect
for condition, Willks’ λ = .828, F(3,49) = 3.39, p = .025, ηp2 = .172, such that, overall,
incremental theory participants performed better than controls.
In separate exploratory analyses, each individual performance metric varied in their
significance but not direction: speech task, p=.061, mental math errors, p=.019, mental math
lowest number, p=.44 (see SOM-R for more detail).
Exploratory analyses of mechanism. To conduct exploratory mediation analyses for
effects on performance, we computed a composite for pre-task appraisals (demands minus
resources), and two cardiovascular reactivity composites (TPR reactivity scores during the
speech and math epochs, and SV reactivity scores during the speech and math epochs), and a
composite of the three performance metrics (see Table S4 in the SOM-R for all zero-order
correlations).
Anticipatory threat appraisals were correlated with subsequent TPR and SV reactivity
during the speech and math epochs, r=.34, p=.014 and r=.38, p=.004, for TPR and SV
respectively. Next, TPR reactivity strongly predicted performance, r=-.37, p=.009, but SV
reactivity did not, r=.11, p=.440. Mediational analysis computed via the Imai et al. (2010)
method found a significant indirect effect of condition on speech and math performance via TPR
reactivity during the speech and math epochs, b=-.13, 95%CI [.02, .32], p=.02, but not via SV
reactivity, b=-.01, 95%CI [-.18, .15], p=.79, (also see Table S3 and Figure S1 in the SOM-R).
Hence this mediation analysis is consistent with the theory that the incremental theory of
personality promoted more adaptive appraisals for an upcoming evaluative task, this reduced
threat-type stress reactivity (TPR) and that allowed individuals to demonstrate improved
cognitive performance.
However, we emphasize caution when interpreting these exploratory mediation results.
Cardiovascular measures have rarely proven useful for definitive mediational tests for effects of
social stress on performance and behavior (see Mendes & Jamieson, 2011). Critically, the
temporal activation of stress responses differs between approach-motivated challenge and
avoidance-motivated threat states. Thus, using the cardiovascular signals from the same temporal
epoch in a regression analysis for both treatment and control can be misleading. Moreover, the
relationship between physiological response and behavioral outcomes are not typically
monotonic as is assumed in most mediation analyses. Furthermore, a key assumption of causal
mediation analysis—temporal precedence—is violated here because physiology and behavior are
measured concurrently. Finally, power calculations for this study were conducted for main
effects, not indirect effects. Nevertheless, these exploratory analyses provide initial evidence in
line with our theoretical expectations and warrant examination in future confirmatory research.
In sum, Study 1 found support for hypotheses: the incremental theory of personality
manipulation improved cognitive, cardiovascular, neuroendocrine, and behavioral reactions to
social stress delineated by the BPS model of challenge and threat. Despite this encouraging
evidence, Study 1 did not examine longer-term stress processes (appraisals or physiological
responses) or accumulated behavioral outcomes (e.g. academic achievement). Nor did Study 1
explore processes in a naturalistic setting; hence conclusions were limited to a controlled
laboratory environment and to a single acute stressor.
Study 2
Study 2 implemented an incremental theory of personality manipulation in 9th grade
classrooms, and collected saliva samples and daily diary reports of social-evaluative stressors.
The focal and pre-registered hypothesis (https://osf.io/e87sn/) was a Daily Stress × Condition
interaction, such that the incremental theory would sever the effect of daily social stressors on
threat appraisals and neuroendocrine responses (similar to Sherman, Bunyan, Creswell, &
Jaremka, 2009; Stephens, Townsend, Hamedani, Destin, & Manzo, 2015; Walton & Cohen,
2011). While a naturalistic daily diary study sacrifices clarity about the nature or timing of the
stressor(s) and makes it more difficult to measure task-specific appraisals, the diary affords a
real-world assessment of a variety of daily social stressors that can contribute undermine health
(Almeida, 2005). As a secondary matter, Study 2 sought to replicate the effect of the incremental
theory of personality on grades observed in previous research (Yeager, Johnson, et al., 2014).
Method
Participants. Study 2 was conducted with 9th grade Algebra 1 students (55.2% female;
56.7% White, 39.7% Hispanic, 3.1% African American) in the first semester of high school,
when threats to social status and academic rank are known to be substantial, pervasive, and
unpredictable (Crosnoe, 2011). Sample size was determined by the maximum number of
participants who were willing to provide consent. There were two analytic samples due to
independent consent processes: one for the intervention and self-reports, and a second for
salivary hormone analysis.
A total of 303 participants consented to complete the intervention and self-report
questions and have their school records analyzed; a sub-sample of these (N = 205) also consented
to provide saliva samples. An attrition analysis found that treatment and control groups did not
differ in terms of the characteristics of those who did not consent to have saliva samples taken
(see SOM-R).
Procedures.
Intervention. Adolescents were randomly assigned—at the individual level (i.e. within
classrooms)— to complete the incremental theory intervention or control materials in their
Algebra 1 classes (see Study 1 for manipulation). Materials were contained in individualized
envelopes, a procedure analogous to affirmation studies (Cohen, Garcia, Purdie-Vaughns, Apfel,
& Brzustoski, 2009). After completing materials, students placed them back in the envelopes and
handed them to experimenters. Materials took 20-30 minutes to complete. Teachers and research
assistants were unaware of hypotheses or intervention content (and were thus blind to condition),
and the messages were never discussed with students after this experience.1
Salivary sampling and self-reports. Saliva samples were collected at baseline (1 or 2
days pre-intervention) and each day 5-9 days post-intervention. All saliva samples were collected
at the same time of day (e.g., students in 2nd period Algebra 1 always provided samples in 2nd
period) to control for diurnal rhythm within individuals. After participants provided a saliva
sample, they completed survey questions assessing daily stressors and appraisals. Samples were
frozen and shipped offsite to be assayed for adrenal hormones: cortisol and DHEA-S (see SOM-
R).
Past research with adults has linked dehydroepiandrosterone sulfate (DHEA-S) to more
adaptive social stress outcomes (Epel, McEwen, & Ickovics, 2010). However, adolescence is a
1 At the request of our funder, fully crossed with the incremental theory of personality
intervention was a brief expressive writing manipulation or control, delivered two days later.
This was not expected to have effects on the outcomes investigated here and was included only
for exploratory purposes; this expectation of a null effect was pre-registered before we received
any data (https://osf.io/6axwy/). Indeed, none of the findings reported here interacted with this
second manipulation nor were they affected by inclusion of that variable in statistical models.
developmental period marked by somewhat different hormonal function than adulthood (Gunnar
et al., 2009; Marceau et al., 2015). In adolescent samples cortisol and DHEA-S are positively
correlated in response to “real world” social stressors, as opposed to laboratory stressors when
they may be negatively correlated (Marceau et al., 2015). Thus, to more fully capture
neuroendocrine effects of the intervention, we assayed both cortisol and DHEA-S and expected
the same patterns for both.
Measures.
Grades. Students’ grades in 9th grade in core subjects (math, English, science, and social
studies) in the fall and spring semesters, and their pre-treatment grades and test scores in the
same subjects, were collected from the school registrar. Ninth grade achievement was a
composite of post-treatment performance in the core subjects and ranged from 0 to 4, and prior
achievement was a composite of the z-scored values for prior grades and test scores.
Daily stressors. Immediately after adolescents provided saliva samples they free-wrote
up to three negative, stressful events in response to an open-ended prompt and then rated the
intensity of the negative event (1 = Not at all negative, 4=Extremely negative). Two independent
coders blind to hypotheses and condition categorized events. In an effort to mirror the TSST
from Study 1—a socially and intellectually evaluative task—participants’ social and/or academic
evaluative stressors were analyzed. Ratings across the three potential stressors were averaged
into a composite for each day.
Threat appraisals. Immediately after listing daily stressors, individuals were asked a
single secondary appraisal item “Overall, how confident are you that you can handle the stresses
you experienced today in school so far?” (10 = I can’t handle the stress at all, 1 = I can handle
the stress really well). Higher values corresponded to saying that they did not have the resources
to meet environmental demands, or a threat appraisal.
Neuroendocrine measures. Cortisol and DHEA-S levels showed highly non-normal
distributions (joint tests of skew and kurtosis, p<.001) and biologically implausible high and low
values. Values were trimmed (top and bottom 1.5% of the distribution). Therefore, our inferences
are limited to the 97% of adolescents in the normal range. A ladder of powers analysis showed
that the optimal transformation of the trimmed data was a square root transformation (see
histograms in the SOM-R for untransformed and transformed data). To facilitate interpretation,
the resulting values were linearly transformed to have the same mean and standard deviation as
the raw data. The same procedure was followed for DHEA-S.
As expected, cortisol and DHEA-S were positively correlated, r=.395, p<.001 (this
correlation was half as strong before trimming and transforming, testifying to the validity of the
method), and so were analyzed both individually and in combination as a single adrenal hormone
variable.
Results
Test of baseline differences. Incremental theory and control condition participants did
not differ across a number of demographic/self-report variables, including gender, ethnicity, prior
achievement, global stress, and depressive symptoms (see SOM-R Table S5). Furthermore, at
baseline, as expected, there was no Daily Stress × Condition interaction predicting threat
appraisals, cortisol, or DHEA-S (ps>.20, see Fig. 2). Moreover, no condition differences in daily
diary reports of social-evaluative stressors were observed at baseline (P=0.29) or post-
intervention (P=0.89). Thus, there were no differences in exposure to social stressors, allowing
for a test of differences in reactivity (see Almeida, 2005).
Replication of treatment effect on grades. Replicating Yeager et al. (2014),
participants assigned to the incremental theory of personality intervention exhibited higher core
course GPA in the fall semester of ninth grade (raw M=2.70, SD=.61) compared to controls (raw
M=2.62, SD=.61), t(298)=2.41, p=.016, d=.279, 95%CI [.05, .49]. The same effect of
intervention on GPA emerged in the spring semester (Control M=2.66, SD=.63, Incremental
M=2.76, SD=.61), t(299)=2.33, p=.020, d=.269, 95%CI [.04, .48]. Analyses of GPA included
prior achievement, AP course enrollment (which can affect grading scales) and gender (a highly
significant predictor of grades) as covariates. Statistical significance was no different when only
controlling for prior achievement. Interestingly, the size of the effect of this social intervention
was analogous to the size of the effect of growth mindset of intelligence and sense of purpose
interventions on grades (Paunesku et al., 2015; Yeager, Henderson, et al., 2014), which explicitly
discussed academic motivation, unlike the present intervention.
Threat appraisals. Appraisals were analyzed using multi-group structural equation
modeling in which a latent daily stress variable—indicated by the five post-intervention daily
stressor reports—predicted a latent threat appraisal variable—indicated by the five daily
appraisal reports, analyzed across treatment and control groups. We used Mplus v 7.11 software
to conduct this analysis (Muthén & Muthén, 2012).
As expected, in the control condition there was a significant effect of daily social-
evaluative stressors on threat appraisals, standardized β = .33, p=.003, 95%CI [.11, .55]. Yet, as
predicted, this relation was severed in the treatment condition, β = .034, p=.738, 95%CI [.24, .
17]. A test of nested models showed a significant reduction in model fit with these paths
constrained to be equal across treatment and control, showing a significant Daily Stress ×
Condition interaction, χ2(1)= 6.577, p=.01. See row 1 in Table 1. These analyses confirm our
first pre-registered hypothesis.
There was no main effect of condition on threat appraisals (see Table S5, SOM-R),
although none was predicted. In a simple effects analysis in a mixed-effects regression model,
the predicted reduction in threat appraisals on high-stress (+1SD) days did not reach significance,
b= 0.275, t(463)= 1.30, p= .194, d=.12, 95% CI [-.02, .30].2
Neuroendocrine responses. Using the same structural equation modeling approach, we
found that, within the control group, there was no relation between reports of daily social-
evaluative stressors and levels of either cortisol or DHEA-S from days 5 to 9 post-intervention
(see rows 2 and 3, column 2, in Table 1; for the full model see Figure S2 in the SOM-R). This
finding represented a failure to find the pattern within the control group, which we then expected
the incremental theory treatment to reduce. This precluded the possibility of carrying out our pre-
registered analysis exactly as planned.
Therefore, we examined the days on which this theoretically expected relation was
present in the control group, and on which we could conduct our pre-registered analysis. Figure 2
shows that the final two days—days 8 and 9 post-intervention—showed a relation between
reports of daily social-evaluative stressors and both cortisol and DHEA-S within the control
group, β = .59, p=.028, 95%CI [.06, 1.12] and β = .58, p=.036, 95%CI [.04, 1.13], respectively.
In a latent variable model that combined cortisol and DHEA-S into a single measure of adrenal
hormones we found an even stronger relation, β = .68, p=.003, 95%CI [.22, 1.13]. Therefore, we
were able to carry out our pre-registered analysis on data from days 8 and 9 post-intervention.
2 Here and throughout, degrees of freedom for mixed effects models were estimated using the
lmerTest package in R (Kuznetsova, Brockhoff, & Christensen, 2015).
As expected, the relation of daily stressors with all neuroendocrine measures became
non-significant among treated individuals: cortisol β = .42, p=.165, 95%CI[1.00, .17], DHEA-S
β = .20, p=.243, 95%CI[.68, .28], HPA-axis latent variable β = .33, p=.243, 95%CI [.80, .15].
A multi-group analysis showed that the relation of daily social-evaluative stressors with cortisol,
DHEA-S, and HPA-axis activation on day 8-9 significantly differed across conditions: cortisol
χ2(1)= 6.54, p=.011, DHEA-S χ2(1)= 4.39, p=.036, HPA-axis χ2(1)= 8.69, p=.003, (see Table 1
and Figure S3 in the SOM-R). In a mixed-effects regression model, there was also a simple
effect for both cortisol and DHEA-S on high-stress (+1SD) days in day 8 and 9, for cortisol, b=
5.53 nmol/l, t(233)= 2.802, p=.006, d=.31 [.09, .52]; for DHEA-S, b= 156.85 pg/ml, t(249)=
3.275, p= .001, d=.36 [.14, .58]. Therefore, this analysis showed support for the hypothesized
Daily Stress × Condition interaction on the final two of the five post-treatment days—the two on
which the expected associations of daily stress and HPA-axis activation were present within the
control group.
Finally, on days 8/9, there was a main effect of the incremental theory intervention on
reduced cortisol, (Control M=10.21, SD=5.38, Incremental M=9.22, SD=5.02), t(233)=2.10,
P=0.037, d=.19, 95%CI [.01, .41], and DHEA-S: (Control M=381.65, SD=287.12,
Incremental M=348.78, SD=289.44), t(249)=2.17, P=0.032, d=.11, 95%CI [.02, .42], but no
main effect for all days (5 through 9), ts<1. See the SOM-R and Fig 3.
Table 1. Association of daily stressors with threat appraisals and HPA-axis hormones, by condition and measurement period,
in Study 2. Notes: Covariates include gender, baseline daily stressor, prior academic performance, baseline hormone levels, day of the
week, and time of day. *** p<.001, ** p<.01, * p<.05, + p<.10.
DV(s)
Control Intervention
Model fit
difference test
NβSE p-values βSE p-values χ2(df) p-values
Threat
Appraisal
(Day 5 – 9) 319 .329 .110 .003** −.034 .103 .738, ns 6.577 (1) .010**
Cortisol
(Day 5 – 9) 192 −.078 .198 .694, ns −.274 .204 .178, ns 0.390 (1) .532, ns
DHEA-S
(Day 5 – 9) 192 .104 .229 .649, ns −.124 .190 .514, ns 0.591 (1) .442, ns
HPA-axis
(Day 5 – 9) 192 .093 .201 .643, ns −.190 .189 .313, ns 1.038 (1) .308, ns
Threat
Appraisal
(Day 8 – 9) 319 .394 .135 .003** −.271 −.141 .054+ 11.941 (1) .0005***
Cortisol
(Day 8 – 9) 181 .591 .269 .028* −.415 .298 .165, ns 6.542 (1) .011*
DHEA-S
(Day 8 – 9) 184 .584 .279 .036* −.199 .243 .412, ns 4.390 (1) .036*
HPA-axis
(Day 8 – 9) 184 .675 .231 .003** −.326 .243 .180, ns 8.688 (1) .003**
Fig. 3. Effects of incremental theory of personality on threat appraisals, salivary cortisol, and salivary DHEAs one week post-
intervention, by level of social/academic evaluative stress reported on a daily diary in Study 2 (figure continued on next page).
Note : Low stress = Low stress day (-1SD), High stress = High stress day (+1SD). Main = main effect of condition. Int = Daily Stress
× Condition interaction. P-value below each plot corresponds to the simple effect of condition estimated at +1SD for daily stress. Point
estimates and p-values estimated in separate linear regression models. Bars correspond to ± 1 standard error of the mean. Day number
corresponds to number of days post-intervention (e.g. Day 5 = the Monday 5 days post-intervention).
Fig. 3. Continued.
Discussion
The present research integrated the biopsychosocial (BPS) model of challenge and threat
with implicit theories of personality to show how beliefs can impact situation-specific appraisals
and regulate responses to social stressors. Adolescents taught an incremental theory of
personality—the belief that people have the potential to change—exhibited improved cognitive,
physiological (neuroendocrine and cardiovascular), and behavioral (task performance) responses
to acute social stress compared to controls (Study 1). Study 2 extended findings by
demonstrating an incremental theory of personality intervention, delivered once in 9th grade
classrooms, reduced HPA-axis activation a week later (cortisol, DHEA-S), especially on high-
stress days, while improving grades 7 months later. Now that these two formal models have been
empirically integrated, this provides a basis for novel predictions and a more holistic picture of
adolescent stress processes.
The present research also helped disambiguate why the socially-oriented implicit theories
of personality intervention—which never mentioned motivation to learn in school—could have
effects on academic performance many months later. Previous research tested for, but did not
consistently find, mediation of implicit theories of personality effects on grades via self-reported
responses to Cyberball ostracism (Yeager, Johnson, et al., 2014). Yet we found that an
incremental theory of personality reduced threat-type reactions known to compromise cognitive
performance, both in the short term (Study 1) and chronically (Study 2), and these mediated
effects on performance (Study 1). In the real-world contexts of high school, adolescents may
struggle making friends, feel excluded or left out by peers, encounter direct victimization, or face
myriad other normal evaluative experiences. Yet coming to view one’s social difficulties as
events that can be overcome, adolescents may appraise them as challenges. Such appraisals
could cause them to exhibit more adaptive coping and perhaps even come to develop closer
relationships—thus setting in motion a positive recursive process that gains strength through its
repetition (Aronson, Fried, & Good, 2002; Blackwell, Trzesniewski, & Dweck, 2007; Jamieson,
Nock, et al., 2013; Walton & Cohen, 2011; Wilson & Linville, 1982; Yeager & Dweck, 2012;
Yeager & Walton, 2011).
A potential limitation of this research involves the unpredicted finding that, in the control
condition in Study 2, daily stressors did not predict adrenal hormone responses until days 8 and 9
post-treatment. However, the data observed in Study 2—combined with the strong evidence in
Study 1—suggest HPA-axis effects were not spurious. First, treatment effects for self-reported
appraisals were found for all post-treatment days. Second, the incremental theory manipulation
improved grades up to 7-months post-treatment. Third, the two different adrenal hormones
showed highly parallel findings on days 8 and 9.
What accounted for this unexpected finding? Negative affect exhibits lagged effects on
consequences of threat-typed stress responses, such as academic achievement (Flook & Fuligni,
2008), or pain and gastrointestinal symptoms (Charles & Almeida, 2006). A failure to return to
homeostasis from prior threat reactions has the potential to accumulate to more maladaptive
responses to subsequent stressors (e.g., Juster, McEwen, & Lupien, 2010; McEwen, 2006).
Indeed, in our study, the first post-manipulation day exhibiting an independently significant
intervention effect on threat appraisals was day 7 (see Figure 3). Neuroendocrine effects on days
8-9 may well be indicative of controls’ failure to return to homeostasis.
Finally, the present experiments may have public health implications, and contribute to
improving adolescents’ stress responses with efficiency at scale, because the incremental theory
intervention can be delivered directly to students with no specialized staff training. At the same
time it will be important to avoid platitudes such as simply telling adolescents that “people can
change” (Yeager & Dweck, 2012). A high priority is to develop more comprehensive methods to
help instantiate an incremental theory. A related priority is to reduce the prevalence of negative
evaluative experiences (such as bullying) so that adolescents have fewer stressors to contend
with in the first place.
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