2008-08-06 10:06:46
By Jennifer Carpenter
Science reporter, BBC News
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Dogs 'catch' human yawns
Yawning is known to be contagious in humans but now scientists have shown that
pet dogs can catch a yawn, too.
The copying activity suggests that canines are capable of empathising with
people, say the researchers who recorded dogs' behaviour in lab tests.
Until now, only humans and their close primate relatives were thought to find
yawning contagious.
The team - from Birkbeck College, University of London - reports its findings
in Biology Letters.
Yawning, although sometimes a response to extreme stress, is more often a sign
of tiredness; but the reason for why yawning is catching is not fully
understood.
Human cues
There is evidence that autistic individuals are less inclined to yawn into
response to another human yawning, suggesting that contagious yawning betrays
an ability to empathise, explained Birbeck's Dr Atsushi Senju.
Dr Senju and his team wondered whether dogs - that are very skilled at reading
human social cues - could read the human yawn signal, and set out to test the
yawning capabilities of 29 canines.
The team created two conditions, each five minutes long, in which a person -
who was a stranger to the dog - was sat in front of the animal and asked to
call its name. Under the first condition, the stranger yawned once the dogs had
made eye contact with them.
"We gave dogs everything: visual and auditory stimulus to induce them to yawn,"
Dr Senju, told BBC News.
Under the second condition, the same procedure was followed, but this time the
stranger opened and closed their mouth but did not yawn.
This was a precaution to ensure that dogs were not responding to an open mouth,
explained Dr Senju.
Yawning yet?
The team found that 21 out of 29 dogs yawned when the stranger in front of them
yawned - on average, dogs yawned 1.9 times. By contrast, no dogs yawned during
the non-yawning condition.
The researchers believe that these results are the first evidence that dogs
have the capacity to empathise with humans; although the team could not rule
out stress-induced yawning - they hope to in future studies.
"Dogs have a very special capacity to read human communication. They respond
when we point and when we signal," Dr Senju told BBC News.
The researchers explained that along with floppy ears and big soppy-eyes,
humans have selected dogs to be obedient and docile. The results from this
study suggest the capacity for empathy towards humans is another trait selected
in dogs during domestication.
Dr Senju thinks that these traits would have been useful to humans when they
began to live side-by-side with canines approximately 15,000 years ago.