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ORIGINAL INVESTIGATION
Acute intranasal oxytocin improves positive self-perceptions
of personality
Christopher Cardoso &Mark A. Ellenbogen &
Anne-Marie Linnen
Received: 22 June 2011 / Accepted: 26 September 2011 / Published online: 20 October 2011
#Springer-Verlag 2011
Abstract
Rationale Research suggests the experimental manipulation
of oxytocin facilitates positive interactions, cooperation,
and trust. The mechanism by which oxytocin influences
social behavior is not well understood.
Objective We explored the hypothesis that oxytocin alters
how people perceive themselves, which could be one
mechanism by which oxytocin promotes prosocial behavior.
Method In a between-subject, randomized, and double-
blind experiment, 100 university students received a 24 I.U.
dose of intranasal oxytocin or placebo, and then completed
the Revised NEO Personality Inventory (NEO-PI-R) and
other self-report measures 90 min later.
Results Intranasal oxytocin increased ratings of NEO-PI-R
extraversion and openness to experiences [F(1,98) = 4.910,
p=.025, partial η
2
=.05; F(1,98)=6.021, p=.016, partial
η
2
=.06], particularly for the following facets: positive
emotions (d=0.48, p<.05), warmth (d=0.47, p<.05),
openness to values (d=0.45, p<.05) and ideas (d= 0.40,
p<.05), trust (d=0.44, p<.05), and altruism (d=0.40,
p<.05). Oxytocin had no influence on ratings of negative
emotionality, conscientiousness, rejection sensitivity, depres-
sion, worry, self-esteem, and perceived social support.
Conclusion The administration of oxytocin improved par-
ticipants’self-perceptions of their personality, at least for
certain traits important for social affiliation. Increased
positive self-referential processing may be one mechanism
by which oxytocin promotes positive social behaviors.
Keywords Intranasal oxytocin .Personality .Trust .
Altruism .Openness .Extraversion .Positive emotion .
Self-perception
Introduction
The nonapeptide oxytocin is known for its role in
reproduction and maternal behavior (Gimpl and Fahrenholz
2001). In the last two decades, oxytocin has gained
recognition for its effects on social behavior in animals
(Carter 1998; Insel 2010). Since it was reported that the
intranasal administration of neuropeptides increases their
levels in cerebrospinal fluid (Born et al. 2002), there has
been an upsurge of interest in experimental manipulations
of central oxytocin in human populations (Bartz and
Hollander 2006; Campbell 2010; Heinrichs et al. 2009).
This body of research shows that oxytocin facilitates
positive interactions (Ditzen et al. 2009; Naber et al.
2010) and improves cooperation, altruism, and trust in a
variety of experimental contexts (Barraza et al. 2011;
Baumgartner et al. 2008; Declerck et al. 2010; Kosfeld et
al. 2005; Mikolajczak et al. 2010a,b).
While the mechanism by which oxytocin facilitates
prosocial behavior is unknown, a common view is that
oxytocin alters how social signals in the external environ-
ment are processed, encoded, and/or interpreted (Bartz et al.
2010a; Ellenbogen et al. 2011; Guastella et al. 2008; Marsh
et al. 2010; Theodoridou et al. 2009). More recently, a
hypothesis has been put forward that oxytocin alters
C. Cardoso :M. A. Ellenbogen (*):A.-M. Linnen
Centre for Research in Human Development,
Concordia University,
7141 Sherbrooke Street West,
Montreal, QC H4B 1R6, Canada
e-mail: mark.ellenbogen@concordia.ca
Psychopharmacology (2012) 220:741–749
DOI 10.1007/s00213-011-2527-6
cognition by increasing the salience of social cues in the
environment (Bartz et al. 2011). One advantage of this
proposal is that it can explain why there are putative
negative behavioral effects of oxytocin (Bartz et al. 2010b;
De Dreu et al. 2010,2011; Shamay-Tsoory et al. 2009).
The view that oxytocin increases attention to social cues is
consistent with recent evidence showing that oxytocin
influences the allocation of attentional resources to
biological motion (Perry et al. 2010) and strengthens the
orienting response to the eye region of the face—an effect
that is associated with increased functional coupling of the
basal amygdaloid nucleus and the superior colliculi
(Gamer et al. 2010).
Past research on intranasal oxytocin has focused
primarily on how information in the external world is
processed or interpreted (i.e., emotional faces, laboratory
games, etc.). As an alternate or complimentary mecha-
nism explaining the effect of oxytocin on social
behavior, oxytocin may alter self-perceptions. That is,
oxytocin may elicit changes in a person’s self-perceived
altruistic, accepting, and socially oriented traits, which
in turn could promote affiliative behavior. There is
some, albeit sparse, evidence consistent with this
proposal. For example, acute intranasal oxytocin improves
self-perceived coping style in humans (Cardoso et al. 2011)
and attachment security in adult males (Buchheim et al.
2009). To further explore this hypothesis, we examined
whether intranasal oxytocin influenced self-reported person-
alityontheRevisedNEOPersonalityInventory(NEO-
PI-R), an instrument with excellent psychometric prop-
erties (Costa and McCrae 1992) and temporal stability
across 6–9 years (Costa et al. 2000). Considering that
personality traits are deemed to be stable and enduring
(Caspi et al. 2005), this study represents an opportunity to
determine whether oxytocin alters core perceptions of the
self. In the context of personality, the tendency to
experience frequent positive emotions and to evoke and
enjoy social interactions characterizes extraversion, while
agreeableness is characterized by prosocial tendencies like
being empathetic, considerate, and helpful. Extraverted
and agreeable children are more socially competent in
their youth and later in adulthood, and these personality
traits are associated with more positive responses from
social partners (Asendorpf and van Aken 2003; Caspi et
al. 2005;Shiner2000). Thus, consistent with the prosocial
literature on oxytocin, oxytocin-induced changes in self-
perception would likely target extraversion and agreeable-
ness, rather than the other core personality factors such as
neuroticism.
We predicted that, relative to placebo, oxytocin would
elicit higher self-report ratings of extraversion and agree-
ableness because these traits are deemed to promote social
affiliation. Because there are no studies in this area, we
included all five factors of the NEO-PI-R in the data
analyses. We also conducted exploratory analyses on the
NEO-PI-R facets (subscales) to follow up significant
findings and to examine a priori predictions based on the
literature (i.e., oxytocin influences trust). To determine
whether oxytocin alters core perceptions of the “social”
self, via the assessment of personality traits, or whether it
alters self-perceptions, in general, we examined the influ-
ence of oxytocin and placebo on participants’self-report of
current depressive symptoms, trait worry, perceived social
support, rejection sensitivity, goal adjustment style, and
global self-esteem.
Method
Participants
A number of 100 healthy university students (50
women) between the age of 18 and 35 were recruited
to participate in this study. Exclusion criteria included
current medication use, presence of a medical illness or
of a current or past mental disorder, lifetime recrea-
tional drug use (with the exception of cannabis, which
required 1-year abstinence and no history of use more
than once every 6 months), smoking, pregnancy, and
poor English language fluency. Exclusion criteria were
assessed using an in-house structured interview proto-
col prior to participation. Participants were queried
about current or past substance use, mental disorders,
use of anti-depressants, anxiolytics, or any psychotropic
medications and psychological treatments. For female
participants, information regarding the menstrual cycle
(date of last menses, average length of cycle) was
collected.
We then randomized 48 (24 women) and 52 (26 women)
participants to an intranasal oxytocin and placebo condi-
tion, respectively. Participants randomized to the oxytocin
and placebo condition were 22.4 ± 3.47 and 21.7 ± 3.35
(mean±SD) years old, respectively. While 4 of 13 women
in the follicular phase and 5 of 13 women in the luteal
phase of their menstrual cycle were taking oral contra-
ceptives in the placebo condition, 5 of 13 women in the
follicular phase and 2 of 11 women in the luteal phase of
their menstrual cycle were taking oral contraceptives in the
oxytocin condition. Statistical tests revealed that the
following variables were balanced across drug condition:
sex [t(98)=0, p>.05], age [t(98)=−0.924, p>.05], menstru-
al phase [t(48)=0.289, p>.05], and oral contraceptive use
[t(48)=1.230, p>.05]. The project was approved by the
Human Research Ethics Committee at Concordia University
(Montréal, Canada), and informed written consent was
obtained from all participants.
742 Psychopharmacology (2012) 220:741–749
Measures
The NEO-PI-R (Costa and McCrae 1992) consists of 240
items that define five factors of personality. High internal
consistency has been reported for the NEO-PI-R, with
coefficients ranging from .89 to .95 (Costa and McCrae
1992), and temporal stability over 6 years (Costa et al.
2000;Herbstetal.2000). In the current sample, internal
consistencies for the neuroticism (α=.93), extraversion
(α=.90), openness to experiences (α=.89), agreeableness
(α=.90), and conscientiousness (α=.91) scales of the
NEO-PI-R ranged from good to excellent.
The Interpersonal support evaluation list—college version
(ISEL; Cohen and Hoberman 1983) is a 48-item inventory
used to evaluate an individual’s perceived social support.
The appraisal scale measures how comfortable an individual
feels discussing their problems with people they know. The
belonging scale measures an individual’saccesstopartners
for social activities (e.g., people to go to the movies with).
The self-esteem scale measures how positively an individual
compares themselves to people they know. The tangible
scale measures an individual’s access to material resources
(e.g., people who can loan them money). Scores range from
0to12oneachscale,withhigherscoresreflectingstronger
endorsement of each category. The internal consistency for
the ISEL (α=.84) in the current sample was good.
The Rejection Sensitivity Questionnaire (RSQ; Downey
and Feldman 1996) is an 18-item inventory that measures
an individual’s sensitivity to rejection during social
exchanges. Scores on this inventory range from 0 to 36,
with higher scores reflecting greater sensitivity to social
rejection. The internal consistency for the RSQ (α= .86) in
the current sample was good.
The Beck Depression Inventory-II (BDI; Beck et al.
1996) is a 21-item inventory that measures depressive
symptoms. Scores on this inventory range from 0 to 63,
with higher scores reflecting more depressive symptoms.
The internal consistency for the BDI (α=.89) in the current
sample was good.
The Rosenberg Self-Esteem Scale (RSE; Rosenberg 1965)is
a 10-item inventory that measures global self-esteem. Scores
on this inventory range from 10 to 40, with greater scores
reflecting higher global self-esteem. The internal consistency
for the RSE (α=.90) in the current sample was excellent.
The Penn-State Worry Questionnaire (PSWQ; Meyer et
al. 1990) is a 16-item inventory that measures trait worry.
Scores on this inventory range from 16 to 80, with greater
scores reflecting higher trait worry. The internal consistency
for the PSWQ (α=.94) in the current sample was excellent.
The Goal Adjustment Questionnaire (GAQ; Wrosch et al.
2003) is a 10-item inventory that measures ability to disengage
and reengage goals. Scores on goal disengagement range from
4 to 20, with higher scores reflecting a greater ability to
disengage from goal attainment. Scores on the goal
reengagement scale range from 6 to 30, with higher scores
reflecting a greater ability to reengage goals. Internal
consistencies for the goal disengagement (α=.86) and goal
reengagement scales (α=.84) were good in the current sample.
Procedure
Participants self-administered a 24 I.U. dose of intrana-
sal oxytocin (Syntocinon, Novartis, Basel, Switzerland)
or a placebo (saline) 50 min prior to participating in the
Yale Interpersonal Stressor, a standardized social rejec-
tion paradigm (Stroud et al. 2000,2002). The stressor
consisted of two staged conversation among three students
(two of them being confederates), where the participant
was increasingly excluded over time from the conversa-
tion. Findings associated with the stress manipulation are
reported elsewhere (Cardoso et al. 2011;Linnenetal.in
press). Both the participant and experimenter were blind to
the content of the nasal spray. Participants’mood was
measured using the profile of mood states (McNair et al.
1988) 10 min before drug administration, 50 min after
drug administration, 65 min after drug administration
(after the first staged conversation), and 80 min after drug
administration (after the second staged conversation). Mood
ratings did not differ between the oxytocin and placebo
conditions at any time point, and at 80 min post-drug
administration, mood ratings (higher scores=more positive
mood) were 136±36 and 139± 34 in the oxytocin and placebo
groups, respectively (Linnen et al. in press). At 90 min post-
administration, participants completed a battery of question-
naires. Participants were then debriefed and asked to rate (1)
how bad they felt in response to the social rejection paradigm
and (2) how stressful they perceived the interaction to be,
which were rated on a five-point Likert scale ranging from 1
(not at all) to 5 (extremely). Participants were then
remunerated Can$50 for their participation.
Statistical analyses
Separate drug × sex multivariate analyses of variance
(MANOVAs) were conducted on the five factors of
personality on the NEO-PI-R, the four scales of the ISEL,
and the two scales of the GAQ. Individual scales and
relevant facets were subsequently probed with univariate
tests to disambiguate statistically significant multivariate
effects or statistical trends. Separate drug × sex analyses of
variance (ANOVAs) were conducted on the ISEL, RSQ,
BDI-II, RSE, and PSWQ, all of which had single measures.
Planned comparisons on facets of the agreeableness factor
of the NEO-PI-R were conducted based on a priori
predictions supported by the literature (e.g., oxytocin
influences trust.)
Psychopharmacology (2012) 220:741–749 743
All statistically significant multivariate effects were
explored for interactions with oral contraceptive use and
menstrual cycle phase in females using MANCOVAs to
determine if additional univariate tests should be
conducted to probe these interactions. Finally, we
examined whether exposure to the interpersonal stressor
prior to completing the battery of tests influenced the
relation between oxytocin and the aforementioned
outcome variables. To do this, we conducted t-tests to
determine if changes in personality paralleled changes in
participant ratings of their subjective stress and negative
affect following social rejection. We also conducted
mediation analysis using Sobel’stestofmediation(1982)
to determine if the effects of oxytocin on the outcome
variables were mediated by the ratings of subjective stress
and negative affect.
Results
Effect of drug administration on personality
We detected a statistical trend for the association between drug
condition and scores on the NEO-PI-R, a statistically significant
effect of sex, and no interaction between drug and sex following
a drug (placebo, oxytocin) × sex MANOVA of the NEO-PI-R
five factors [drug: Wilks’1=.896, F(5,92)= 2.146, p= .067; sex:
Wilks’1= .845, F(5,92)=3.383, p=.008; drug × sex: Wilks’1
=.986, F(5,92)=0.270, p=.928]. Women (116.70± 17.56)
scored higher than men (106.64 ± 20.39) on the agreeableness
factor of the NEO-PI-R [F(1,98)= 7.032, p= .009, partial η
2
=.07]. No significant sex differences were found on the
remaining scales of the NEO-PI-R (data not shown).
Participants reported higher extraversion and openness to
experiences following oxytocin administration (see Fig. 1),
but we did not detect a statistical association between drug
condition and neuroticism, agreeableness, or conscientious-
ness [extraversion: F(1,98)=4.910, p=.025, partial η
2
=.05;
openness to experiences: F(1,98)=6.021, p=.016, partial
η
2
=.06; neuroticism: F(1,98)=0.381, p=.539; agreeable-
ness: F(1,98)=0.397, p=.530; conscientiousness: F(1,98)=
0.001, p=.981)].
Oxytocin administration was associated with higher
ratings of positive emotions (d=0.48, p<.05) and warmth
(d=0.47, p<.05) on the extraversion scale, and openness to
values (d=0.45, p<.05) and ideas (d=0.40, p<.05) on the
openness to experience scale following planned compar-
isons on facets of the NEO-PI-R. Since the literature
indicates that oxytocin augments prosocial behavior, we
conducted additional analyses on facets of the agreeable-
ness factor. Ratings of trust (d=0.44, p< .05) and altruism
(d=0.40, p<.05) were higher following oxytocin adminis-
tration. Statistics describing the facets of the extraversion,
openness to experiences, and agreeableness factors can be
found in Table 1.
Examining potential confounds: oral contraceptives,
menstrual phase, and the impact of the interpersonal stressor
We investigated a possible confounding relation between
oxytocin, personality, oral contraceptive use, and menstrual
phase. We did not detect a statistical interaction between
oral contraceptive use and drug condition, or between
menstrual phase and drug condition on scores on the NEO-
PI-R following a drug × oral contraceptive use (no, yes)
MANCOVA, controlling for menstrual phase (follicular,
luteal), and a drug × menstrual phase MANCOVA,
controlling for oral contraceptive use [drug × contraceptive
use: Wilks’1=.960, F(5,41) = 0.342, p=.884; drug ×
menstrual phase: Wilks’1=.865, F(5,41) =1.280, p= .291].
For this reason, we did not conduct further univariate tests
to probe these interactions.
We investigated a possible confounding relation
between oxytocin, personality, and social rejection
(which preceded completion of the questionnaire bat-
tery). If such a relation existed, we anticipated that
ratings of stress and negative affect would parallel
changes in personality across drug condition, or mediate
the relation between oxytocin and personality. Ratings
of stress did not differ between those administered
oxytocin (1.93± 0.98) and those administered placebo
[2.14± 0.91; F(1,96) = 1.135, p= .289]. Ratings of negative
Fig. 1 Total scores on the five personality scales of the NEO-PI-R in
participants who self-administered intranasal oxytocin (n=48) or a
placebo (n=52). Error bars represent 1 standard error. *p<.05
744 Psychopharmacology (2012) 220:741–749
affect (i.e., how bad did you feel?) did not differ between
participants administered oxytocin (2.02± .96) and those
administered placebo [2.19±1.05; F(1,96)=0.719, p=.399].
Furthermore, the effect of oxytocin on personality was not
mediated by stress or negative affect, respectively, using the
Sobel’s test of mediation (1982) [extraversion (z=−1.041,
p=.297; z=−0.574, p=.566); openness to experiences
(z=1.203, p=.229; z=0.759, p=.448); warmth (z=−0.171,
p=.864; z=0.305, p= .760); positive emotions (z=0.771,
p=.440; z=−0.397, p=.691); openness to ideas (z=0.182,
p=.855; z=−0.573, p=.567);opennesstovalues(z=0.022,
p=.983; z=0.141, p=.888); trust (z=−0.249, p= .803;
z=−1.306, p=.191); altruism (z=0.267, p=.790; z=0.576,
p=.565)]. In summary, we found no evidence that oral
contraceptive use, phase of menstrual cycle, or stressor-related
effects influenced the relation between oxytocin and personality.
Effect of drug administration on clinical symptoms, social
support, and other questionnaires
Descriptive statistics for the measures to follow are
presented in Table 2. We detected no statistical relation
Table 1 Descriptive statistics
for subscales of the NEO-PI-R
by drug condition
*p<.05
a
N=48
b
N=52
Variable Oxytocin
a
Placebo
b
95% CI Cohen (d)
Mean SD Mean SD LL UL
Warmth (E1)* 23.15 4.17 21.06 4.45 0.37 3.80 0.47
Gregariousness (E2) 18.83 4.57 18.23 5.06 −1.32 2.52 0.13
Assertiveness (E3) 17.58 5.31 15.81 5.30 −0.33 3.88 0.33
Activity (E4) 18.33 3.80 18.06 3.08 −1.09 1.66 0.08
Excitement-seeking (E5) 21.75 4.81 20.38 4.84 −0.55 3.28 0.28
Positive emotions (E6)* 23.33 4.54 20.77 5.84 0.49 4.64 0.48
Openness to fantasy (O1) 22.29 4.59 20.61 4.79 −0.19 3.54 0.35
Openness to aesthetics (O2) 21.54 5.95 20.14 5.34 −0.83 3.65 0.25
Openness to feelings (O3) 23.15 4.82 22.04 3.71 −0.59 2.81 0.26
Openness to actions (O4) 19.60 4.03 18.81 3.88 −0.77 2.37 0.21
Openness to ideas (O5)* 24.42 4.92 22.04 6.56 0.06 4.69 0.40
Openness to values (O6)* 20.15 4.87 17.04 5.11 0.25 3.32 0.45
Trust (A1)* 20.15 4.87 17.89 5.11 0.28 4.25 0.44
Straightforwardness (A2) 17.04 5.55 17.13 5.13 −2.21 2.03 −0.02
Altruism (A3)* 23.56 3.63 21.94 4.30 0.03 3.21 0.40
Compliance (A4) 15.88 4.37 16.42 4.84 −2.38 1.29 −0.12
Modesty (A5) 15.90 5.28 16.90 5.49 −3.15 1.13 −0.19
Tendermindedness (A6) 20.44 3.91 20.19 4.33 −1.40 1.89 0.06
Table 2 Descriptive statistics
for perceived social support,
global self-esteem, depressive
symptoms, trait worry,
rejection sensitivity, and goal
adjustment style
a
N=48
b
N=52
Oxytocin
a
Placebo
b
Variable Mean SD Mean SD
Interpersonal support evaluation list (ISEL)
Appraisal 10.71 1.99 10.40 2.47
Belonging 8.21 2.39 8.19 2.72
Self-esteem 8.79 1.98 8.48 2.26
Tangible 10.40 1.78 10.10 1.72
Rejection sensitivity (RSQ) 8.18 3.20 7.83 3.56
Rosenberg’s self-esteem (RSE) 21.85 4.93 21.54 5.39
Beck depression inventory (BDI) 6.83 5.78 6.44 6.75
Penn-state worry (PSWQ) 42.54 13.12 43.90 13.82
Goal adjustment questionnaire (GAQ)
Goal disengagement 11.69 1.53 11.37 1.41
Goal reengagement 22.40 4.32 22.18 4.21
Psychopharmacology (2012) 220:741–749 745
between drug condition and the four subscales of the ISEL
(social support), a statistical trend for the effect of sex, and
no interaction between drug condition and sex following a
drug × sex MANOVA [drug: Wilks’1=.984, F(4,93) =
0.373, p=. 827; sex: Wilks’1=.920, F(4,93) = 2.018,
p=.098; drug × sex Wilks’1=.986, F(4,93)= 0.270,
p=.928]).
We detected no statistical relation between drug condi-
tion and the two subscales of the GAQ (goal engagement),
no effect of sex, and no interaction between drug condition
and sex following a drug × sex MANOVA (drug: Wilks’
1=.988, F(2,95)=0.575, p=.565; sex: Wilks’1=.999,
F(2,95)=0.062, p=.940; drug × sex: Wilks’1=.999,
F(4,93)=0.040, p=.961).
Women (46.02±13.51) scored higher on the PSWQ (trait
worry) than men [40.48±12.91; F(1,96) = 4.240, p= .042,
partial η
2
=.04], and our analyses revealed an interaction
between sex and drug condition on scores on the BDI
(depressive symptoms), as well as a statistical trend for the
interaction between sex and drug condition on scores on the
RSE [global self-esteem; BDI drug × sex: F(1,96) = 4.581,
p=.035; RSE drug × sex: F(1,96) = 3.072, p=.083)].
Follow-up analyses revealed no statistically significant
effect of drug on the RSE or BDI in men or women [RSE
men: t(48)=1.05, p=.299; women: t(48)= −1.420, p= .242);
BDI men: t(48)=−1.924, p=.063; women: t(48)=1.185,
p=.242].We did not detect a statistical relation between
drug, sex, and the interaction between drug and sex
with any other variable [RSQ (rejection sensitivity)
drug: F(1,96)=0.265, p=.608; sex: F(1,96)=0.016,
p=.898; drug × sex: F(1,96)=0.237, p=.627); BDI drug:
F(1,96)=0.098, p=.754; sex: F(1,96)=0.018, p=.894,
RSE drug: F(1,96)=0.094, p=.760; sex: F(1,96)= 0.173,
p=.678, PSWQ drug: F(1,96)=0.261, p=.610; drug × sex:
F(1,96)= 0.246, p=.621].
Discussion
The results of the present experiment indicate that intrana-
sal oxytocin changes how participants perceive and report
self-referential information deemed to be enduring and
stable. Participants who self-administered intranasal oxyto-
cin reported higher ratings of extraversion and openness to
experiences than participants administered a placebo.
Specifically, personality traits characterized by positive
emotions, warmth, trust, altruism, and openness to values
and ideas were most sensitive to oxytocin administration.
The pattern of results was strikingly consistent with the
experimental literature (Ditzen et al. 2009; Kosfeld et al.
2005; Marsh et al. 2010)—only scales related to social
behavior were altered by the administration of intranasal
oxytocin relative to a placebo, with the exception of
openness to experiences. The effects of oxytocin on self-
perceptions showed remarkable specificity. Oxytocin had
no effect on how participants perceived their trait negative
emotionality, conscientiousness, rejection sensitivity, worry,
self-esteem, symptoms of depression, or ability to disen-
gage from thwarted goals. Moreover, oxytocin had no
impact on participants’perceptions of their external social
environment, in that it had no measurable impact on any of
the perceived social support subscales assessed. Impor-
tantly, these findings cannot be attributed to mood change
or changes in the perceived stressfulness of the social
rejection paradigm, which all study participants experi-
enced prior to completing questionnaires. Neither the mood
(Linnen et al. in press) nor subjective stress ratings were
influenced by intranasal oxytocin. This is consistent with
other research that suggests oxytocin does not have an
appreciable effect on self-reported emotional states (Alvares
et al. 2010; Kirsch et al. 2005; Kosfeld et al. 2005). These
data suggest that oxytocin modulated self-perceived per-
sonality (i.e., core traits) without modulating how partic-
ipants responded to social rejection (i.e., current emotional
state).
These present results warrant consideration in the
broader context of the experimental work on oxytocin.
Recent evidence suggests intranasal oxytocin has differen-
tial effects on social behavior depending on contextual
factors (Bartz et al. 2011). For example, intranasal oxytocin
has been shown to improve altruism only for people
perceived to be part of an individual’s group, and not for
people perceived to be part of an out-group (De Dreu et al.
2010,2011). Furthermore, oxytocin did not improve social
cooperation when social partners were perceived to be
untrustworthy (Mikolajczak et al. 2010a,b), uncooperative
(Declerck et al. 2010), or antagonistic (Shamay-Tsoory et
al. 2009; but see Baumgartner et al. 2008 for an exception).
Other research suggests that the effect of oxytocin on
cooperative behavior depends on characteristics of the
individual (Andari et al. 2010; Bartz et al. 2010a,2011).
Taken together, there is a need to better understand the
context- and person-dependent effects of oxytocin on social
behavior, which now include changes in self-perception.
The findings have important implications regarding the
influence of oxytocin on human social behavior. We
contend that increased self-perception of positive trait
characteristics in response to oxytocin is consistent with a
frame of mind that is tailored to the acquisition of new
social relationships. This may occur, in part, via three
distinct changes in information processing: increased
salience of social stimuli (Bartz et al. 2011; Gamer et al.
2010; Perry et al. 2010), facilitated processing of positive
interpersonal stimuli in the environment (Marsh et al. 2010;
Unkelbach et al. 2008), and increased positive self-
referential processing. Changes in the processing of
746 Psychopharmacology (2012) 220:741–749
external positive social stimuli may enable approach
behavior (i.e., identifying cues that signal potential social
interactions), while changes in positive self-referential
processing may facilitate and reinforce actual social
interactions (i.e., promoting reciprocal and affiliative social
behavior). In support of the latter contention, oxytocin
improves self-perceived attachment security (Buchheim et
al. 2009) and coping style (Cardoso et al. 2011).
In contrast to the findings for extraversion, the effect of
oxytocin on openness to experiences was unexpected. The
factor is defined as the active seeking and appreciation of
experiences for their own sake (Caspi et al. 2005; Costa and
McCrae 1992) and could theoretically facilitate the devel-
opment of new relationships. Alternatively, the effect of
oxytocin on increasing openness to experiences may be
associated with a recent finding that oxytocin, relative to
placebo, increases suggestibility during hypnosis (referred
to as “hypnotizeability;”Bryant et al. 2011). Openness to
experiences and hypnotizeability are known to correlate
(Glisky et al. 1991). Thus, it is possible that oxytocin-
induced changes in self-perceived openness to experiences
parallel behavioral changes in suggestibility. Clearly, the
relation between openness to experiences, oxytocin, and
suggestibility warrants further investigation.
A number of study limitations warrant consideration.In the
current study, the battery of questionnaires was administered
to participants after a social rejection paradigm. It is possible
that the reported findings are the result of a combined effect of
social rejection and the drug manipulation. For example, it
could be argued that oxytocin “prevented”astress-induced
decline in extraversion and openness to experiences, as
opposed to increasing self-report ratings of these personality
factors. While we cannot definitively rule out this possibility,
it is unlikely for at least two reasons. If oxytocin prevented a
stress-induced decline in personality ratings, one would
expect to see similar changes in ratings of mood and
subjective stress, which are more sensitive to interpersonal
stress than trait measures of personality. Participants’ratings
of negative mood (Linnen et al. in press) and subjective stress
did not differ between the oxytocin and placebo conditions.
Mediation analyses further supported our contention: ratings
of subjective stress failed to mediate the relation between
drug administration and personality. In addition, participants’
scores on the NEO-PI-R were within the normal range and
were comparable to an age-matched sample that did not
undergo an interpersonal stress challenge or drug adminis-
tration. For example, 102 participants from a previous study
(Ellenbogen et al. 2011) who did not experience a social
rejection stressor scored 114.03 on extraversion, whereas
participants in the present sample during the placebo
condition scored 114.31.
History of mental illness was assessed using self-report,
and it is possible that some participants had undiagnosed
mental disorders that could have been screened using a
structured diagnostic interview. The placebo nasal spray
contained saline solution, but none of the pharmacologically
inactive compounds found in the oxytocin spray. Thus, it is
possible that the findings observed in the present study could
be due to the effects of a nonactive compound administered
with oxytocin. The present findings should be interpreted in
light of a number of methodological issues in the study of
intranasal oxytocin in humans including the absence of data
on dose–response individual differences (i.e., absorption
rates). Timing issues also warrant some consideration. While
most studies examine the effects of oxytocin 45 min after
administration (Ditzen et al. 2009; Kosfeld et al. 2005), there
was a 90-min delay between testing and drug administration
in the present study. It is unlikely that the delay had any
impact on the results, as previous research has shown that
peptide concentrations in the cerebrospinal fluid remain
relatively stable even 80 min after administration (Born et al.
2002). Furthermore, we have reported effects of oxytocin on
cognition that can still be detected at 85–115 min post-
administration (Ellenbogen et al. 2011). Finally, it should be
noted that while we did not find an effect of menstrual cycle
or contraceptive use in the current study, self-report methods
are not entirely reliable, and more subtle hormonal inter-
actions may only become evident with use of better measures
(e.g., hormone assays).
An important implication of this research is that hormones,
which fluctuate abreast changing life events (i.e., getting
involved in intimate relationships, which putatively increases
endogenous oxytocin (Diamond 2004), can influence the
self-reporting of purportedly stable and enduring traits.
Furthermore, these data provide one explanation of how
contextual effects (DeLongis and Holtzman 2005)influence
the reporting of traits. In summary, the present study builds
on previous experimental work to show that intranasal
oxytocin influences how people perceive themselves, which
is pertinent to our understanding of the role of oxytocin in
affiliative behavior.
Acknowledgments This research was supported by grants to Dr.
Ellenbogen from the Canadian Institutes of Health Research and the
Canada Research Chair program (supported by the Social Sciences
and Humanities Research Council of Canada). Christopher Cardoso is
supported by a scholarship from the Natural Sciences and Engineering
Research Council of Canada.
Conflict of Interest None
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