Adolescent chimps and humans share risk-taking behaviour: Study

NewsDrum Desk
24 Jan 2023

Washington, Jan 24 (PTI) Adolescent chimpanzees share some of the same risk-taking behaviours as human teens, but they may be less impulsive than their human counterparts, according to a new research.

The study gets at age-old nature-or-nurture questions about why adolescents take more risks: because of environment or because of biological predispositions? It is published by the American Psychological Association, US.

"Adolescent chimpanzees are in some sense facing the same psychological tempest that human teens are," said lead researcher Alexandra Rosati, University of Michigan, US.

"Our findings show that several key features of human adolescent psychology are also seen in our closest primate relatives," said Rosati.

According to the study, the researchers conducted two tests involving food rewards with 40 wild-born chimpanzees at a sanctuary in Republic of Congo.

The chimpanzees voluntarily participated in the games in order to receive food treats, the study said. The research is published in the Journal of Experimental Psychology: General.

Chimpanzees can live to be 50 years old and experience adolescence at about 8 to 15. Like humans, chimpanzees show rapid changes in hormone levels during adolescence, start forming new bonds with peers, show increases in aggression and compete for social status, the study said.

According to the study, in the first test, adolescent and adult chimpanzees could choose between two containers in a gambling task. One container always contained peanuts, a food that chimpanzees somewhat like. The other container concealed either a disliked food - a cucumber slice - or a favourite food - a banana slice. The chimpanzees could play it safe and get the peanuts, or take a chance for some coveted banana at the risk of ending up with unappetizing cucumber, the study said.

The scientists recorded the chimpanzees' emotional reactions and vocalizations, including moans, whimpers, screams, banging on the table or scratching themselves. Saliva samples also were collected to track hormone levels, the study said.

During several rounds of the test, adolescent chimpanzees took the risky option more often than adult chimpanzees, but adolescents and adults had similar negative reactions when they received cucumber, the study said.

The study also included a second test, modelled after the famous "marshmallow test" with human children, which examined delayed gratification where chimpanzees could receive one banana slice immediately or wait for one minute to receive three slices.

Both adolescent and adult chimpanzees chose the greater delayed reward at a similar rate. Human teens tend to be more impulsive than adults so they would be more likely to take the immediate reward, the study said.

"Prior research indicates that chimpanzees are quite patient compared with other animals, and our study shows that their ability to delay gratification is already mature at a fairly young age, unlike in humans," said Rosati.

However, adolescent chimpanzees weren't happy about waiting for the extra banana slices and they threw more tantrums during the one-minute delay than adult chimpanzees, the study said.

Risk-taking behaviour in both adolescent chimpanzees and humans appears to be deeply biologically ingrained, but increases in impulsive behaviour may be specific to human teens, said Rosati. PTI KRS KRS KRS

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