The surprising behavior of human adolescents may seem like a unique aspect of human adolescence.
But sword blows and bullying may be a throwback to our primate ancestors, as youngsters return to their “inner chimpanzees” during turbulent adolescence, according to scientists.
A study of young chimpanzees found that they exhibited the same risk-taking behavior and pessimism as young chimpanzees.
Lead researcher Dr., an associate professor of psychology and anthropology at the University of Michigan.
“Our findings suggest that some key features of human adolescent psychology are also seen in our closest primate relatives.”
Chimpanzees can live to be 50 years old and go through puberty at about eight to 15 years old.
Adolescent humans and chimpanzees seek risky options
Just like humans, chimpanzees show rapid changes in hormone levels during adolescence, begin to form new bonds with their peers, show increases in aggression and compete for social status.
Researchers played two games with 40 wild chimpanzees in a sanctuary in the Republic of the Congo to find out if other aspects of their behavior mirror those of young humans.
In the first test, chimpanzees were always asked to choose between a box containing peanuts and a box containing either a cucumber slice or a banana slice.
Chimpanzees could secure the job and choose peanuts, or gamble on winning a tasty banana, risking ending up with an unappetizing piece of cucumber.
During several rounds of testing, adolescent chimpanzees were 55 percent more likely than adults to choose the risky option.
This suggests that adolescent chimpanzees, just like adolescents, will seek the riskier option if there is a greater reward.
In the second test, the chimpanzees’ “deferred gratification” skills were tested by allowing the chimpanzees to immediately grab a banana slice or wait one minute to get three slices.
Risk-taking behavior ‘deeply biologically ingrained’
Young people tend to be more impulsive than adults, so they are more likely to receive immediate reward.
Although young chimpanzees delayed their rewards by the same amount as adults, they had more tantrums during the one-minute delay than adult chimps.
This suggests that, unlike humans, adolescent chimpanzees are no more impulsive than adults, but are just as bad at losing as adolescents.
“Previous research has shown that chimpanzees are quite patient compared to other animals, and our study shows that, unlike humans, their ability to delay gratification is already mature at a fairly young age,” Rosati said.
“Risk-taking behavior in both adolescent chimpanzees and humans appears to be deeply ingrained biologically, but increases in impulsive behavior may be unique to human youth.”
The research has been published online in the Journal of Experimental Psychology: General.