By Dr. Becker
If you share your life with a beloved pet, you already know that humans have the capacity to feel empathy for other species. But do other species have the same ability?
To begin to answer that question, researchers at the Yerkes National Primate Research Center at Emory University in Georgia set out to investigate the extent and flexibility of empathy in chimpanzees, since they are the closest relatives to humans. They published their findings earlier this year in the Proceedings of the Royal Society B.1
Researchers Use Contagious Yawning to Test Chimp Empathy
For the study, the researchers used contagious yawning as a gauge of involuntary empathy. According to study author Matthew Campbell, PhD, "Copying the facial expressions of others helps us to adopt and understand their current state." The closer we feel to a person, the more likely we are to “catch” their facial expressions, which is why the researchers believe empathy is involved. In addition, this form of mirroring occurs subconsciously, which implies that the trust between the individuals happens at a deep level as well.
The Yerkes researchers used yawns rather than other more subtle contagious facial expressions simply because yawns are easy to see.
The experiment involved 19 adult chimps at Yerkes, all of whom were raised in captivity by other chimps.
Chimpanzees ‘Caught’ the Yawns Not Only of Familiar Humans, But Also Unfamiliar Humans
The researchers discovered that the chimpanzees showed contagious yawning to 3 out of 5 target groups. They yawned in response to the yawns of familiar chimpanzees, familiar humans, and even unfamiliar humans. They did not respond to unfamiliar chimpanzees or an unfamiliar species (gelada baboons).
According to Campbell:
"That humans known and unknown elicited empathy similarly to group members, and more than unknown chimpanzees, shows flexibility in engagement. We can use this information to try to influence this flexible response in order to increase empathy toward unfamiliar chimpanzees, and we hope we will be able to apply such knowledge to humans as well.”
Interestingly, the chimps watched the videos of unfamiliar chimps more than any other. The study authors believe the chimpanzees’ high level of interest combined with lack of contagious response could be the result of hostility toward unfamiliar chimps that overrides feelings of empathy.
In general, however, the chimps in the study showed flexibility by having an empathetic response with a different species (humans), including unfamiliar members of that species. The researchers believe these results suggest that human empathic flexibility is shared with related species, in this case, chimpanzees.
Chimps Raised in Captivity Probably View Humans as Acceptable
The Yerkes researchers further concluded that the chimps’ responses were a result of life experiences. Because they’ve been raised in captivity, the chimps have been conditioned to accept humans, and in fact, meeting new humans may provide opportunities for new positive interactions.
In the wild, chimpanzees are defensive and unfriendly to strangers, so unfamiliar chimps provoke an automatic hostile response. And according to the researchers, baboons have zero significance in the world of captive chimps, which is probably why the chimps weren’t interested in them.
This study was a follow up to a 2009 study that showed contagious yawning in chimpanzees is not just about sleepiness or boredom, but is also a sign of a social connection between individuals. The study authors hope in the future to learn if there are certain experiences that might lead chimpanzees to be less hostile toward strange chimps, with an eye toward increasing empathy in humans as well.