What is the Effect of Affect on Bonobo and Chimpanzee Problem Solving?

Abstract

Humans have two close relatives, the bonobo and chimpanzee, whose psy- chologies differ in ways that will allow for insights into the evolution of our own species. Unfortunately, we know little about bonobos due to their late classifica- tion as a species, their scarcity in captivity and the remote location of their natural habitat. Here I review some of the first experimental comparisons of bonobos and chimpanzees, suggesting that their socioecology has shaped their psychology. First, consistent with the observation that bonobos live in more predictable environments, bonobos value future food payoffs less than chimpanzees, while also avoiding the risky foraging decisions that chimpanzees prefer. Second, consistent with the pre- diction that more predictable environments allow bonobos to be more egalitarian, it was found that bonobos are capable of more flexible cooperative behavior than chimpanzees if the joint problem requires high levels of tolerance. Overall, these comparisons suggest that it is selection on the emotional reactivity of bonobos and chimpanzees that likely played a large role in shaping their differing psychologies, which raises the possibility that changes in human temperament may have also been crucial for the evolution of the unique psychology of our own species as well.