Dogs can catch yawns from humans, regardless of whether they are familiar with the person, according to a study. The authors of the paper say their findings question the idea that contagious yawning is a sign of empathy in mammals.
The authors of the paper published in the journal Proceedings of the Royal Society B looked at data from six existing studies involving 257 dogs in total. The experiments included seeing whether dogs would catch yawns off people who interacted with them—for instance by petting the animal—and others who ignored them.
Co-author Patrick Neilands, a Ph.D. student at the Clever Canine Lab part of the Animal Minds research group at New Zealand’s University of Auckland, told Newsweek the study provides the first robust evidence that yawning is contagious in dogs, which until now hasn’t been shown in any mammals outside of humans and chimpanzees.
This suggests contagious yawning is “evolutionary ancient,” said Neilands.
The team set out to answer whether dogs catch yawns, and if this is affected by who is yawning and potential feelings of empathy towards that individual. The researchers defined empathy as “emotional and mental sensitivity to another’s state.”
Some argue that early in the evolution of mammals, a mechanism developed whereby the brain picks up on another individual’s state. The hypothesis goes that this results in the observer experiencing a similar state, and in turn encourages mammals to aid others. Researchers have in the past hypothesized that contagious yawning could be an example of this. Existing studies have suggested people with lower levels of empathy are less likely to catch yawns; while female mammals are more likely to because they are more likely to be directly involved in taking care of offspring and therefore might have greater levels of empathy.
However, the team could not find evidence in dogs to support the hypothesis that mammals are more likely to catch yawns if they are familiar with the yawner, if the individual is male or female, or because they might feel empathy.
“This is powerful evidence against the contagious yawning-empathy hypothesis and rules out using contagious yawning as an indirect signal of empathy in other animals,” the authors wrote.
The authors argue the propensity to help could be down to something more simple and not linked to empathy, like the desire for social contact.
Contagious yawning in animals, meanwhile, could be down to stress, a means of communication, or a way to improve collective vigilance, they said.
However, the researchers added: “That is not to say that some non-human animals do not necessarily experience some form of empathy but that contagious yawning cannot be taken as a diagnostic signal for the presence of these empathetic processes.”
Neilands said: “Our finding that contagious yawning is not a reliable indicator of empathy was very surprising.
“Unfortunately, there doesn’t appear to be any shortcuts in untangling the evolutionary roots of empathy! However, while this is disappointing, we hope our findings can act as impetus for researchers to develop better, more direct tests of empathy in non-human animals.”
He continued: “While the main focus of our paper is on whether contagious yawning is a reliable signal of empathy in general, our finding that contagious yawning is present in dogs (as well as in humans) reflects the fact that there is substantial similarity in dogs’ and humans’ social cognition.
“This similarity between human and dog social cognition is fascinating to many researchers and some argue that dogs have cognitive adaptations to enable them to communicate with and live in close proximity to humans.”