By Shreya Dasgupta
Contagious yawning has long been linked to empathy: humans and apes yawn more in response to the yawns of their kin and friends. Now, scientists studying yawn contagion have shown that humans may not always be the most empathetic species. Their results, published today (August 12) in PeerJ, show that humans yawn more than bonobos only when close family and friends trigger the yawns. In the presence of mere acquaintances, however, humans and bonobos showed similar yawn sensitivity.
“It seems that the basal level of empathetic capacity is the same in the two species,” said Elisabetta Palagi from the Natural History Museum at the University of Pisa in Italy, who co-led the study. “But when an emotional bonding comes into play, people overcome bonobos.”
Matthew Campbell, a primatologist at California State University Channel Islands who was not involved with the work, agreed. “These are interesting results,” Campbell wrote in an e-mail to The Scientist. “They show that the most basic form of empathy, also called emotional contagion, appears to work very similarly in humans and bonobos, who are as closely related to us as chimpanzees.”
Several studies have examined empathy in great apes and humans separately. But the present study is the first to directly compare empathetic abilities between species, according to Palagi. “This has probably not been done before because quantifying empathy in animals is difficult,” she said. “In addition, most empathy studies in humans have used questionnaires and direct interviews, which cannot be replicated in bonobos.”