Emotional Apes: Chimpanzees and Bonobos Pout with Games of Chance

It can be frustrating when something doesn't go your way--and apparently apes feel the same way. Researchers have discovered that, like humans, chimpanzees and bonobos exhibit emotional responses to the outcomes of their decisions by pouting or throwing angry tantrums--especially when a risk-taking strategy fails to pay off.

In order to study the emotional responses and motivations of chimpanzees and bonobos, researchers travelled to an African sanctuary called the Tchimpounga Chimpanzee Sanctuary. There, the scientists presented the apes with two different types of problems. One problem allowed the apes to make choices about whether or not to wait to obtain larger rewards; the other problem allowed the animals to make choices about whether to take a chance to obtain a high-quality treat. With the second problem, though, there was a risk of obtaining a non-preferred food item if their gamble didn't pay off.

"Psychologists and economists have found that emotions play a critical role in shaping how humans make complex decisions, such as decisions about saving or investing in money," said Alexandra Rosati from Yale University in a news release. "But it was not known if these processes are shared with other animals when they make decisions about their important resources--such as food."

It turns out that humans do share this in common with apes. After testing both chimpanzees and bonobos, the researchers found that both species displayed emotional responses to their choices. Yet there were differences between the two species. Chimpanzees were more patient and less likely to take risks than bonobos, for example. Yet when a choice led to a less preferred outcome, both of the species displayed negative emotional responses, which included vocalizations similar to pouts and moans, scratching and banging. In addition, the apes would try to change their responses if a bad outcome occurred.

The findings are important in the study of these species and also in the study of evolution. It turns out that like humans, apes exhibit emotional responses to decision-making. That said, further research is needed in order to determine whether these emotional responses to outcomes can change the apes' future choices and decisions.

The findings are published in the journal PLOS One.