Scientists have long wondered about the "prosocial" activity of bonobos, noting how the apes appear to be more sharing and cooperative than other primates such as chimps, per the Los Angeles Times. But humans may still have them beat after a new study out of Duke University suggests bonobos prefer "jerks" rather than more helpful subjects, a release notes—perhaps setting humans apart from our closest kin in the animal kingdom. The study, which appears in the Current Biology journal, notes that by the time human infants are 3 months old, they exhibit a preference for more helpful people, but "whereas humans already prefer helpers by [that age], bonobos favor hinderers." The researchers went to work on this theory via four experiments on semi-free-ranging bonobos in a Democratic Republic of Congo sanctuary.
The scientists used both live-action participants and animated videos to see if the bonobos preferred "prosocial" or "antisocial" actors. In one experiment, for example, the bonobos had to choose whether to accept apple slices from a "helper" (someone the apes had previously seen return a dropped toy to someone who'd dropped it) or a "hinderer" (someone who'd taken that toy and run away). The bonobos tended to reach out to the thief. The researchers theorize the apes may think such insolent behavior is a signifier of dominance and social status, and by choosing the bully, they'd avoid being bullied themselves and increase their chances of getting food or mates. That trait may keep bonobos from working together in large groups like humans. (Bonobos are the closest humans can get to a "living ancestor.")