Photo: Ben Cranke/Getty Images

We may idealize youth, but there’s a good chance we’ve got it all wrong — some researchers believe we’re happiest in our later years, after a dip in middle age begins to reverse itself around 50. By the time you hit 85, according to one study, odds are you’ll feel better about your situation than you did at 18.

There are a few perks to this stage of life than often go unsung. Yes, the wisdom and the discounts and the life satisfaction are probably pretty nice. But so, I bet, is the ability to be cranky in public and have people find it charming. The shoes get much more comfortable, too. And then there’s the matter of your social circle: As we age, we tend to cull the number of people we hang out with — we become less socially active overall, but more likely to spend our socializing time on people we’re close to, rather than casual acquaintances or throwaway friendships.

And so, according to a study published last week in Current Biology, do monkeys. When the authors observed a group of Barbary macaques at a French wildlife park, ranging from age 4 to age 29 — which, one researcher told the New York Times, translates to around 105 in human years — they noticed that starting at around age 20, the monkeys became less likely to groom, play with, approach, or generally engage in social contact with the other animals.

One way that psychologists have explained our narrowing social circles is something called socio-emotional selectivity theory: the idea that as we age, we become more aware that our time is fleeting, and thus more determined to spend it on our most meaningful relationships. But that explanation doesn’t account for why monkeys — who likely don’t contemplate their own mortality — exhibit the same behavior. “I don’t think monkeys have any awareness of their death, so if there are any changes in their behavior, they’re obviously not to do with that,” Dario Maestripieri, a biologist at the University of Chicago, told New Scientist. “Maybe we would behave similarly even if we had no awareness of our own death.”

An alternative explanation, the study authors speculated to the Times, may be that the monkeys may become more risk-averse with age, less willing to take chances on unfamiliar peers. Or perhaps they’re just more easily exhausted by socializing, and so stick to the most comfortable, least effortful relationships.

Regardless of the reason, though, the fact that we share this distinct pattern with our primate cousins suggests that the reasons may be more biological than social. “Our behaviors that seem very much the result of our deliberation and choice,” study author Alexandra Freund, a developmental psychologist at the University of Zurich, told the Times, “might be more similar to our primate ancestors than we might think.” New Scientist also highlighted these similarities in a video titled “Is Your Grandma Like an Old Monkey?” — a question worth asking, but maybe not a comparison you want to bring up to Grandma herself. At this age, she’s earned some respect.