Study shows midlife crisis in monkeys

Chimpanzees and orangutans in the midlife crisis?

22.11.2012

Scientists have found in apes similar fluctuations of the mental state in the life course, as they are also observed in humans. In adolescence, the monkeys experience an exhilaration of well-being that gradually diminishes until the middle of life and then rises again. The scientists speak here of a U-curve of well-being during the life course.

The international team of researchers led by Andrew Oswald of the University of Warwick (England) and Alexander Weiss of the University of Edinburgh (Scotland) have studied in more detail the progress of well-being in the life of chimpanzees and orangutans, in terms of possible parallels with that of humans well-known phenomenon of mid-life crisis. Previous theories „emphasize sociological and economic factors“ as the cause of the crisis in the middle years of life, but the researchers could now prove that this evidently an evolutionary predisposition exists. The modern, youth-oriented lifestyle, everyday stress, debts or past separations or divorces, therefore, have a much lower impact on the midlife crisis than previously thought. Their results published the researchers in the trade magazine „Proceedings of the National Academy of Sciences“ (PNAS).

Well-being of 500 apes studied
The sense of well-being decreasing towards the middle of life causes many people considerable problems with aging. You can now console yourself with the idea that the predisposition to this mid-life crisis is evidently evolutionary and has already been laid in your cradle. For apes also show a comparable decline in well-being in middle age. Researchers led by Andrew Oswald and Alex Weiss examined the well-being of 155 Japanese zoo chimpanzees, 181 zoo chimpanzees in the United States and Australia, and 172 orangutans from zoos in the United States, Canada, Australia and Singapore , The mood of the 508 apes was documented by the animal caretakers, volunteers and scientists, who were very familiar with the individual animals. The condition of the animals was described with factors as they characterize the mood in humans.

Monkeys and humans show mood low to mid-life
In all samples, the researchers found a U-shaped course of well-being in the life of the monkey. The low point reached the well-being of the animals at an age between 28 and 35 years what „comparable to the human minima of well-being between the ages of 45 and 50 years“ be, the scientists report in the journal „PNAS“.

Evolutionary midlife crisis?
According to the scientists, the evolutionary biological approach has so far gone far short in explaining the midlife crisis. „Although apes have a close genetic relationship with humans and share many behavioral traits, including culture and use of tools“, be a comparable study, as the current, so far not been carried out. The researchers around Andrew Oswald and Alexander Weiss had hoped, according to their own information, that due to the close relationship between apes and humans, similarities in the degree of well-being over the lifespan can be seen. But „You never know what comes out of studies“, explained Weiss and was pleased, „that the results match those of many other areas.“ Your „Findings will impact on scientific and socio-scientific theories, and may help to identify ways to improve the well-being of humans and monkeys.“, so the conclusion of the scientists. (Fp)

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