Contagious yawning is thought to represent a
basic form of empathy involved in state
matching. Despite recent evidence in support of
this connection, the neurochemical basis of
contagious yawning remains largely unknown.
Here, we investigate whether intranasal
oxytocin, a hormone and neuropeptide involved in
empathic processing, bonding and social
affiliation, influences contagious yawning among
human participants in a laboratory setting.
Using a double blind procedure, 60 male
college students received 30 IU of intranasal
oxytocin or placebo and were then recorded
during exposure to a conta- gious yawning video
stimulus.
Contrary to the empathic modeling
hypothesis, oxytocin did not increase contagious
yawning but rather appeared to modulate its
expression in ways indicative of an enhanced
awareness of the social stigma associated with
this behavior. In particular, individuals in the
oxytocin condition were more likely to conceal
their yawns and less likely to display overt
cues associated with the behavior.
Follow-up research could explore how social
context and affiliation with the target stimulus
alter this response.
Résumé
La contagion du bâillement semble
représenter une forme d'empathie basique.
Malgré des preuves récentes
à l'appui de ce lien entre contagion et
empathie, la base neurobiochimique de cette
contagion du bâillement reste inconnue.
Dans cet article, les auteurs explorent si
l'ocytocine intranasale, une hormone et
neuropeptide impliquée dans les
mécanismes de l'empathie, l'accouplement
et l'affiliation sociale, participe à la
contagion du bâillement parmi les membres
d'un laboratoire de recherche. En utilisant une
procédure en double aveugle, 60
étudiants de sexe masculin ont
reçu 30 UI d'ocytocine intranasale ou un
placebo. Puis leurs bâillements on
été enregistrés
après que leurs soit projetée une
vidéo de bâillements comme
stimulus.
Contrairement à l'hypothèse de
la modulation de l'empathie par l'ocytocine, son
instillation nasale n'a pas augmenté la
propension à être sensible à
la contagion du bâillement mais est
plutôt apparue comme modulant son
expression, comme si l'ocytocine accentuait une
prise de conscience de la stigmatisation sociale
associée à ce comportement. En
particulier, les individus sous l'influence de
l'ocytocine étaient plus susceptibles de
dissimuler leurs bâillements et moins
susceptibles d'afficher ostensiblement leurs
bâillements. La poursuite de cette
recherche pourrait explorer la façon dont
le contexte social et le vécu de la
contagion du bâillement modifient la
réponse contagieuse.
1. Introduction
Contagious yawning is triggered by sensing
or thinking about the action in others
[1], and has been hypothesized to
represent a basic form of involuntary empathy
rooted in a perception- action mechanism known
as state matching or emotional contagion
[2]. Platek et al. [3] first
provided empirical support for this in humans by
demonstrating a positive relationship between
conta- gious yawning and the ability to
inferentially model the mental states of others
(i.e., mental state attribution). This empathic
modeling hypothesis has subsequently been
supported by over a dozen empirical
investigations, demonstrating lines of support
at the behavioral, clinical, psychological, and
neuroanatomical lev- els [reviewed by 4; but
see 5]. Most recently, a study reported that
college students scoring higher on psychopathic
personality traits showed reduced contagious
yawning [6]. Therefore, conta- gious
yawning could be used as a key behavioral marker
when studying social psychological development.
Despite the potential importance of
understanding the proximate mechanisms of this
response, the neurochemical basis of contagious
yawning remains largely unknown.
In mammals, oxytocin is a neuropeptide known
to facilitate positive social interactions, and
it is released during pair bonding, maternal
care, sexual behaviors, and forming normal
social attach- ments [7]. Oxytocin has
also been implicated in various forms of
empathic processing [reviewed by 8]. For
instance, the experience of empathizing with
others has been shown to release oxytocin
[9], and variation in oxytocin receptor
genes predicts scores on empa- thy measures
[10]. Accumulating research indicates
that oxytocin is primarily involved in cognitive
forms of empathy [11], including mind
reading and perspective taking
[12&endash;15]. However, intranasal
oxytocin has also been shown to increase
emotional empathy in men [16].
Since previous research has independently
linked both conta- gious yawning and oxytocin
with empathy and perspective taking, we were
prompted to investigate whether intranasal
admin- istration of oxytocin modulates
contagious yawning frequency. Consistent with
the existing literature, we hypothesized that,
in comparison to placebo, intranasal oxytocin
would enhance this response.
4. Discussion
This is the first study to investigate the
influence of oxytocin on contagious yawning.
Despite the role of oxytocin in various forms of
empathic processing [reviewed by 8], and
accumulating evidence supporting the empathy
modeling hypothesis of yawn contagion
[3,6], our results fail to demonstrate
an increase in contagious yawning following the
administration of intranasal oxytocin in the
laboratory. However, the expression of
contagious yawning was modulated by this
treatment. For instance, participants receiving
oxytocin spray showed a significant discrepancy
between the self- reported urge to yawn and
actual yawning during the experiment, and those
that did yawn took an average of nearly 40 s
longer to do so following exposure to the video
stimulus. Furthermore, analy- ses of the
associated behaviors accompanying yawns
demonstrated that participants in the oxytocin
condition were less likely to dis- play overt
cues associated with yawning (i.e., sighing or
stretching) and made more attempts to cover up
their yawns during the exper- iment. It is
possible that intranasal oxytocin activated
mechanisms involved in diminishing and/or
concealing this response. Since yawning in the
presence of others is considered rude and often
thought of as a sign of boredom or disrespect
[26], and oxytocin has been shown to
enhance social awareness [e.g.,27,28],
we inter- pret these findings as oxytocin
producing a greater awareness of the social
stigma related to the behavior.
The behavioral effects of oxytocin on social
cognition are com- plex, context dependent, and
vary across individuals [reviewed by
29], and thus, it remains possible that
intranasal oxytocin could enhance the frequency
of contagious yawning in other set- tings. The
current study was limited in that we only
sampled males and their response to unfamiliar
video stimuli in a confined laboratory setting.
Since oxytocin primarily enhances prosocial
behavior, empathy and affiliation with perceived
ingroup mem- bers [reviewed by 30], and
observational research has documented that
people are more likely to yawn in response to
yawns of friends and family members in
comparison to acquaintances and strangers
[31], follow-up research could assess
the influence of intranasal oxytocin on
contagious yawning in mixed sex groups of
varying social closeness in more naturalistic
settings.
While the current findings provide no
evidence for an increase in contagious yawning
following oxytocin administration, this
treatment did modulate the expression of yawning
whereby participants were less likely to display
overt cues accompanying yawns and were more
likely to conceal the behavior by cover- ing
their mouth during the act. Therefore, it seems
that intranasal oxytocin produced an enhanced
awareness of the social stigma associated with
the behavior. Future research in this area may
shed light into the relationship between
contagious yawning, empathy and mental state
attribution.
