{"id":314392,"date":"2020-10-22T14:00:39","date_gmt":"2020-10-22T18:00:39","guid":{"rendered":"https:\/\/news.harvard.edu\/gazette\/?p=314392"},"modified":"2023-11-08T20:13:17","modified_gmt":"2023-11-09T01:13:17","slug":"aging-chimps-show-social-selectivity","status":"publish","type":"post","link":"https:\/\/news.harvard.edu\/gazette\/story\/2020\/10\/aging-chimps-show-social-selectivity\/","title":{"rendered":"Why do we get so picky about friendship late in life? Ask the chimps"},"content":{"rendered":"\n\t
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Three males groom together in a chain \u2014 Likizo (a younger male) grooms Big Brown (an older male), who grooms Lanjo (another younger male). <\/p>

Photo by John Lower<\/p><\/figcaption><\/figure>\n\n\t

\n\t\t\t\n\t\t\tScience & Tech\t\t<\/a>\n\t\t\n\t\t

\n\t\tWhy do we get so picky about friendship late in life? Ask the chimps\t<\/h1>\n\n\t\n\t\t\t<\/div>\n\t\t\n\t
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\n\t\tJuan Siliezar\t<\/p>\n\t\t\t

\n\t\t\tHarvard Staff Writer\t\t<\/p>\n\t\t\t\t\t<\/address>\n\t\t<\/div>\n\n\t\t

\n\t\t\tNew study shows nonhuman animals get selective socializing during aging\t\t<\/h2>\n\t\t\n<\/header>\n\n\n\n
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No new friends and no drama.<\/p>\n

When humans age, they tend to favor small circles of meaningful, established friendships rather than seek new ones, and to lean toward positive relationships rather than ones that bring tension or conflict. These behaviors were thought to be unique to humans but it turns out chimpanzees, one of our closest living relatives, have these traits, too. Understanding why can help scientists gain a better picture of what healthy aging should look like and what triggers this social change.<\/p>\n

The work is described in the Oct. 23 issue of the journal Science<\/a> and is authored by a team of psychologists and primatologists, including current and former researchers from the Harvard Department of Human Evolutionary Biology<\/a>.<\/p>\n

The study draws on 78,000 hours of observations, made between 1995 and 2016. It looked at the social interactions of 21 male chimpanzees between 15 and 58 years old in the Kibale National Park in Uganda. It shows what\u2019s believed to be the first evidence of nonhuman animals deliberately selecting who they socialize with during aging.<\/p>\n

The researchers looked only at male chimpanzees because they show stronger social bonds and have more frequent social interactions than female chimps. Analyzing a trove of data, the researchers saw that the chimpanzees displayed much of the same behavior aging humans exhibit.<\/p>\n

The older chimpanzees they studied, for instance, had on average more mutual friendships\u00a0while younger chimps had more one-sided relationships. Mutual friendships are\u00a0characterized by behavior such as reciprocated grooming whereas in lopsided friendships\u00a0grooming isn\u2019t always returned.<\/p>\n

Older males were also more likely to spend more time alone and showed a preference for interacting with \u2014 and grooming \u2014 chimps they deemed to be more important social partners, like other aging chimps or their mutual friends. And like older humans looking for some peace and quiet, the chimpanzees showed a shift from negative to more positive interactions as they reached their twilight years. The preference is known as a positivity bias.<\/p>\n\r\n\n

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Kakama and Makoku grooming together; these males are long-term mutual friends and show a high level of tolerance. <\/p>

Video by Ronan Donovan<\/p><\/figcaption>