Our Closest Ancestors the Apes Reveal Evolutionary Link to Mid-Life Crisis

We've all heard of the well-known "mid-life crisis"; you know, where you hit middle age and run out and buy that expensive sports car, have an affair on your long-term spouse, and engaging in other impulsive behaviors. But we might not be the only species that suffers from feelings of depression that lead to mid-life crises.

Researchers recently collected data on 500 captive apes, including Chimpanzees and Orangutans, and caregivers for the animals were asked to rate the apes' mood (whether it tends to be positive or negative) and how much pleasure the ape receives from various situations. These responses were averaged to determine the general happiness of the apes. Surprisingly, humans aren't so unlike their ancestors–the apes' happiness tended to reach an all-time low point around 32 years of age (which is middle-aged for an ape) and then steadily increased until death.

The results of the study suggest that their may be something evolutionary to our mid-life crises. First, brain changes across development may lead to the outcome of a mid-life crisis, or our ability to deal with our emotions may improve over time with a dip at middle-age. Alternatively, there may be a link between happiness and longevity, with unhappier primates dying off sooner than their happier counterparts. There are limitations to the stuy, and its had its criticisms, but the results are still interesting in that they reveal that their may be something beyond humanity that motivates our inexplicable behaviors.