As people get older, they become choosier about how they spend their time and with whom they spend it. Now, researchers reporting in the Cell Press journal Current Biology on June 23 find, based on a series of experimental and behavioral studies, that similar changes take place in Barbary macaques. The findings offer an evolutionary perspective on why aging humans behave as they do, according to the researchers. “With increasing age, the monkeys became more selective in their social interactions,” Almeling says. “They had fewer ‘friends’ and invested less in social interactions. Interestingly, however, they were still interested in what was going on in their social world.”
Overall, the studies suggest that, just like humans, monkeys become more selective as they age: they select social over non-social information, and they are more selective regarding their social interactions. However, the reduced social behavior is not due to a general loss of interest in others. “Changes in social behavior in monkeys and humans may occur in the absence of a limited time perspective and are most likely deeply rooted in primate evolution,” concludes Alexandra Freund from the University of Zurich, who was also involved in the study.