Feelings of depression and regret we might have in common with the apes, though our penchant for sports cars seems to be uniquely human.
A recent study of over 500 great apes, including chimpanzees and orangutans, across several regions, measured the general happiness of the primates through responses from their caretakers and handlers. The study specifically asked questions regarding the mood of the animals, as well as the level of pleasure they derive from social situations. Averaging the responses, the study determined the happiness and well-being levels of each ape, with the results showing a U-shaped curve of happiness when plotted against age.
Dr. Alexander Weiss, psychologist and lead author, told BBC Nature, "What we are testing is whether the U-shaped curve can describe the association between age and well-being in non-human primates as it does in humans." A younger ape, like their human counterpart, is generally happier, while apes entering the middle of their lives, somewhere around 30 years old, dip in their happiness level. As an ape ages beyond their middle years, happiness increases again, creating the U shape.
While this isn't to say that our middle-aged ape brethren will ever be on the market for a shiny new sports car, there are other potential implications such as "mating with more females or gaining access to more resources," said Weiss. Ultimately, given the differences in our societies, and the similarities in happiness over our life spans, it is likely that there is some biological and physiological basis for the phenomenon. "We have to look deeper into our evolutionary past and that of the common ancestors that we share with chimpanzees, orangutans and other apes."
Source: BBC Nature