In a bitter disappointment for dog lovers everywhere, scientists have found dogs don’t yawn at the same time we do because of any special human-canine bond.
While contagious yawning is well documented in chimpanzees, the evidence is much more mixed for other non-human mammals, including man’s best friend. While some studies suggest that dogs engage in contagious yawning, other studies have no found no effect.
In humans, many scientists think contagious yawning is the result of what they call the “perception – action” mechanism which, in our case, is connected to our ability to empathise – to match the emotional or mental state of another person. Empathy is key to human society, allowing us to co-operate and to care about others.
Could contagious yawning be a similar signal of empathy in dogs?
In a new study, researchers from the University of Auckland’s Clever Canine Lab in the School of Psychology tested contagious yawning in dogs by doing a ‘study of studies’ of previous research from around the world involving 257 dogs, followed by an experiment involving 32 dogs in the lab in Auckland.
The experiment used different scenarios to test dogs’ yawning response including having handlers behave differently towards them – in one scenario the handler was very friendly, playing and stroking the dog, but in the other the dog was ignored and, when it obeyed a command, the handler ate the treat instead of giving it to the dog. In each case, the handler stood in front of the dog and yawned at set intervals to study its response.
In the ‘study of studies’ data analysis, the researchers also investigated whether there was any difference in dog response to a yawner who was familiar to them and one who wasn’t, and any difference between female dogs and male dogs.
Both parts of the study came up with the same answer – dogs do engage in contagious yawning but were no more likely to yawn if they knew their handler, or whether the handler had been friendly. Female dogs did not contagiously yawn more than male dogs.
“Contagious yawning does not appear to be a reliable signal of empathy in dogs or other mammals according to our work,” says doctoral candidate and study author Patrick Neilands.
“Sadly, there appear to be no shortcuts in untangling the mystery of the evolution of empathy in humans but by studying other species we hope to one day solve the puzzle of when and why empathy first emerged."
The research is published in Proceedings of the Royal Society B.