This study aimed to clarify whether infants
and preschool children show susceptibility to
contagious yawning, a well-known effect that has
been demonstrated experimentally in older
children and adults by exposing them to video
sequences showing yawns. In a first study,
parents kept a log of their child's yawns for a
one week period. None of the log entries
reported any contagious yawns by the children.
Although less frequent than in older children
and adults, spontaneous yawning by infants and
preschoolers showed the typical morning,
post-wakening peak, and an increase before
bedtime in the evening. In an experimental
study, infants and preschoolers watched a
presentation that included many images of
yawning and a repeated video clip of their own
mother yawning, but there was no evidence of
contagious yawning. The results suggest that,
even when witnessing yawns by someone with whom
they have a strong and positive emotional
relationship, very young children do not show
contagious yawning.
1. INTRODUCTION
Despite its ubiquity, human yawning remains
poorly understood from psychological, functional
and developmental perspectives [1]. With
regard to the latter, yawn-like activity has
been reported in the foetus [2].
Premature babies yawn less frequently as
homeostatic control of sleeping and waking
states improves [3]. Children in their
first year of primary school yawned up to five
times more frequently than in their final year
of kindergarten [4]. According to
parental reports, by the age of 12 years
children yawn around nine times per day
[5], which is similar to the 7-9 times
per day reported by adults [6], but
lower than the 11 and 23 times per day reported
for adult 'morning types' and 'evening types',
respectively [7].
One intriguing but understudied aspect of
yawning in young infants is its so-called
contagiousness. In adults, yawns seen on video
induce yawning in approximately half of young
adult observers [8]. Platek et al.
reported a correlation between susceptibility to
video-induced contagious yawning in adults and
questionnaire measures of empathy [9].
In an experimental study of contagious yawning
in children, there were no yawn-inducing effects
of video yawn stimuli in children below 5 years
of age; susceptibility increased throughout
primary school years and reached adult-like
levels by 12 years of age [10]. The
absence of contagious yawning in preschoolers
contrasted with earlier reports of imitation of
facial (including mouth) movements by neonates
and 1year-olds [11,12].
In the study by Anderson & Meno
[10] the yawning model in the video (a
young adult female) was unfamiliar to the
children. Given that model identity and empathy
may be important factors in socially facilitated
behaviour, including imitation [13,14],
here we presented young children with a highly
familiar yawning model, one with whom they are
likely to have a strong and positive emotional
relationship. This study had two principal aims.
First, given the paucity of information on the
spontaneous occurrence of yawning in preschool
children, we asked mothers to keep a log of
yawning by their children. Second, we assessed
susceptibility to contagious yawning
experimentally, using video stimuli in which the
model was the child's own mother.
4. GENERAL DISCUSSION
No parent who submitted a log made any
reference to contagious yawning by the child.
Furthermore, experimental exposure to yawn
stimuli failed to induce yawning in preschool
children. Together, these observations suggest
that, as originally reported by Anderson &
Meno [10], infants and preschoolers
appear largely immune to contagious yawning, in
marked contrast to older children and adults.
Furthermore, the failure to show contagious
yawning occurs even when the model is an
emotionally significant one.
Although devoid of any reference to
contagious yawning, the log data revealed young
children's natural 'yawn profiles' to be similar
to those reported for adults. However, the
overall daily mean frequency of yawns reported
by parents for their children (2.2) was much
lower than frequencies reported by adults
recording their own yawns (7-9: [6];
11-23: [7]). Given the much higher
frequencies of spontaneous yawning reported in
schoolchildren [4,5], it seems likely
that parents missed some of their child's yawns,
and/or disproportionately recorded yawns when in
close proximity to the child, such as when
putting the child to sleep, or at mealtimes.
More research is required to clarify the normal
daily range of yawns for young infants and
preschool children.
The largely negative results from the video
study confirm that infants and preschoolers are
much less susceptible to psychological
influences on yawning when compared with older
children and adults [10]. This is in
spite of the fact that the yawning model on
video was the child's mother; therefore, even a
positive emotional bond with the model appears
insufficient to elicit contagious yawning in
very young children. This is one context in
which the 'Bonding- and Identification-based
Observational Learning' model [13] may
not apply. The absence of contagious yawning in
very young children suggests that different or
additional brain mechanisms underlie yawning in
older individuals, and also that neonatal and
infant imitation of facial movements
[11,12] are based on different neural
mechanisms to those involved in contagious
yawning.
It should be noted, however, that certain
aspects of the experimental procedure might have
reduced the likelihood of obtaining contagious
yawning. For example, general arousal from
attending to the stimulus presentation,
including the novelty of seeing the mother
yawning on the video monitor, might have
inhibited yawning. Indeed, the artificiality of
experimental video sessions may inhibit yawning
in some adult participants (see [17]).
Researchers should, therefore, aim to increase
the ecological validity of ivestigations into
contagious yawning, such as by using live
models, and incorporating various real-life
contexts.
