The question: Because of a phenomenon widely known as the midlife crisis, men of a certain vintage, for reasons still not entirely understood, sometimes feel compelled to blow their life savings on things like a Porsche. Evidence of the often wallet-breaking condition has been found "in many datasets across human cultures," Alex Weiss, a psychologist at Edinburgh University, tells The Guardian. While the existential burden may help finance the sports car industry, its exact origin still remains a mystery. To get a better understanding of the origins of the midlife crisis, an international team of researchers from the U.S., Japan, Germany, and the U.K. tested whether apes, our closest living relatives, faced similar demons as they aged.

How it was tested: Using the U-shaped curve of happiness that humans experience over their lifetimes — a sense of well-being in youth that dips to a low in 50s age range and picks up again afterwards — as a basis, researchers looked at more than 500 chimps and orangutans of varying ages from different zoos, sanctuaries, and research centers from all over the world to see if the same happiness curve could be applied. The apes were chosen because they had similar genetics, physiology, social pressures, and stress factors. Scientists catalogued each animal numerically, rating each ape's well-being and happiness levels by asking their keepers a series of questions about the animal's behavior.

The outcome: Apes experience a similar "lull in happiness" in their middle-age years, says Ian Sample at The Guardian. In captivity, great apes often live to 50 or more, and the animals often posted the lowest well-being scores around age 30.

What experts say: Researcher Dr. Alexander Weiss, a primatologist and evolutionary psychologist at the University of Edinburgh in Scotland, says that like humans, middle-age chimps and orangutans experience more anxiety and less pleasure than their younger peers, and aren't as successful at getting what they want. "You'd probably see it in their posture." Senior author Andrew Oswald said the results make "one's head spin." Whether the changes are hormonal, related to brain structure, or due to other factors will need to be investigated in future studies. The positive takeaway, says Oswald, who describes himself as "58 and very happily accelerating," is that all humans are designed to suffer a similar low before things get inevitably better. In other words: A midlife crisis is "completely normal," and it's "apparently out of your control."