Two recent experiments continue the current trend of highlighting how empathy benefits the social development of chimpanzees and bonobos, a trait that has also been shown to benefit the social development of humans.
One of the studies, conducted at the Tacugama Chimpanzee Sanctuary in Sierra Leone, found that as chimpanzees age they can “catch” yawning from humans, a trait that suggests empathy.
Scientists from Lund University studied a total of 33 orphaned chimpanzees at the sanctuary. Researchers divided the chimpanzees into two age groups, 12 from 1 to 4 years old, and 21 from 5 to 8 years old. To model yawning, gaping and nose wiping, the scientists alternated between using human testers who were familiar to the chimpanzees and using those who weren’t.
The findings revealed that only the older chimpanzees were susceptible to catching yawns from humans. The younger group did not “catch” any of the movements. The studies also showed that the chimpanzee’s familiarity with the human conducting the test was irrelevant.
“All the inhibitions that we have in our emotional lives are present in chimpanzees and bonobos.”“The results of the study reflect a general developmental pattern, shared by humans and other animals,” researcher Elaine Madsen said. “Given that contagious yawning may be an empathetic response, the results can also be taken to mean that empathy develops slowly over the first years of a chimpanzee’s life.”
Past studies have shown that orphaned chimpanzees, compared to those with mothers, lack social skills. Now, a new study by Dr. Frans de Waal and Zanna Clay, a postdoctoral fellow also at Emory University, found that bonobos with mothers have a more developed sense of empathy.
As published in the Proceedings of the National Academy of Sciences, the scientists studied thirteen adult, eleven adolescent, and twelve juvenile bonobos at the Lola Ya Bonobo sanctuary in the Democratic Republic of the Congo. The group had both orphaned and mother-raised bonobos.
The researchers measured the time it took individual bonobos to recover after stressful events (e.g. an attack by another bonobo) and found adolescents were more likely than adults to console others after the events. They also found that, among juveniles, mother-raised bonobos were three times more likely to console a “victim” as were orphan bonobos.
The researchers also looked at the other side of the equation and measured the time it took individuals to “recover” after a stressful event. They found that the ones who were the slowest to recover were the ones who showed the least empathy toward others. They were often orphan bonobos.
“We found that the individuals who are the slowest to get out of their distress are the ones who have the least attention to the distress of others,” de Waal said.
Their research also revealed that the length of playtime correlated to being raised with a mother. Those raised by their mothers tended to play longer than the orphans, suggesting, according to the scientists, a higher level of social development. This leads de Waal to conclude that “all the inhibitions that we have in our emotional lives are present in chimpanzees and bonobos.”
And, clearly, that includes empathy.