Centre for
Brain and Cognitive Development Birkbeck
College, Malet Street, London
Contagious yawning (i.e.,
yawning triggered by perceiving others' yawning)
is a well-documented phenomenon, but the
mechanism underlying it is still unclear. In
this chapter, I review the current evidence
about (a) developmental studies with typically
and atypically developing population and (b)
comparative studies in non-human animals.
Developmental studies have revealed that
contagious yawning is disturbed in individuals
with Autism Spectrum Disorders, suggesting that
contagious yawning may share a developmental
basis with the capacity for theory of mind.
Comparative studies have suggested that
contagious yawning can be observed in
non-primate species such as domestic dogs. As
dogs are known to have exceptional skills in
communicating with humans, it has also been
suggested that contagious yawning may be related
to the capacity for social communication. These
results from developmental and comparative
studies are consistent with the claim that the
mechanism underlying contagious yawning relates
to the capacity for empathy.
Lack
of contagious yawning in autism
Even among the normal
population, it's likely that people react
differently to seeing someone near them yawn.
Within normal adults, there can be huge
individual variability related to contagious
yawning. We test the theory that contagious
yawning is affected in people with autism. The
yawning faces triggered more than twice as many
yawns in non-autistic children than in their
autistic counterparts. This kind of yawning is
thought to be based at least partly on the
capacity for empathy, which is compromised in
autistic persons. There's likely to be a
continuum, with autistic people and possibly
others with similar social deficits lying at the
extreme end.
Dogs
catch human yawns
The dog has a special
relationship with humans, going beyond that of
other domestic animals. Recent evidence suggests
this comes from domestication rather than wolf
behaviour, perhaps involving something as simple
as a change in natural looking behaviour. The
selection of dogs that were more communicative
and aware of human emotions then wolfs, probably
helped them to be so empathic. "As the dog's
amazing skills to read human communication cues
are thought to have been selected by human over
last 15,000 years, it is also possible that the
same evolutionary process affected their skills
to empathise with humans". We review the
behavioral capacity of dogs to catch human yawns
looking like human contagiosiness, showing that
dogs possess the capacity for a rudimentary form
of empathy.
