Green monkeys follow social traditions

2023-12-20 01:54:09

Researchers from the Department of Ecology and Evolution of the University of Lausanne (Switzerland) have revealed the existence of social traditions in vervet monkeys green monkeys (Chlorocebus pygerythrus), who follow different social “norms” and respond to “group pressure”, as published in the magazine iScience (1).

“We report the existence of behavioral traditions of social customs in vervet monkeys that are stable over 9 years,” says Elena Kerjeanfrom the University of Lausanne and the Paul Sabatier University of Toulouse (France).

Social learning

The researchers discovered that such differences in social traditions They established differences in the “social atmosphere” that could be transmitted from one generation to the next through social learning.

Males who dispersed quickly adapted their social style to that of their new group, suggesting that they may experience a phenomenon similar to social conformity driven by peer pressure.

Interestingly, they also found that males who dispersed quickly adapted their social style to that of their new group, suggesting that they may experience a phenomenon similar to social conformity driven by peer pressure.

Kerjean and his colleagues, including Erica van de Waal y Charlotte CanteloupDid you know Other animals, like people, follow traditions. But most studies had focused primarily on the presence or absence of traditions, such as tool use. They had not explored more subtle quantitative differences in social behavior which can give rise to important differences in the social atmosphere of a group.

To delve deeper into the new study, the researchers analyzed more than 84,000 social interactions between almost 250 individuals of vervet monkeys collected over nine years in three neighboring groups. His analysis revealed an unexpected difference: in one of the groups, called Ankhase (AK), the monkeys were more likely than the other two groups to exchange when grooming each other.

“We found that individuals in one group – AK – showed significantly more affiliative behaviors than those in the other two groups, and this difference remained stable over 9 years of study,” says Kerjean.

The AK group was not only more sociable than the other two, but they also exchanged grooming more reciprocally. When one monkey groomed another, the latter returned the favor. As a result, grooming was fairer in the AK group than in the other two.

Social conformity

“You can think of it as an exchange of massages between individuals,” Kerjean explains. “If I give you a massage 100 times a year but you’ve only had it twice, I can feel that our relationship is quite unfair. That’s the kind of differences we observed between our groups.

The researchers also found that six males who moved from one group to another adapted their social interactions to better fit their new groups. These changes were also observed in both directions. Leaving the AK group, males became less social and less likely to groom their mate fairly. Males who left one of the less social groups for AK showed exactly the opposite trend.

“The males adapted their sociality to the group with which they integrated, which we believe is a good example of social conformity,” emphasizes Kerjean.

“This normative rule of acting like others probably helps them integrate better into a new group,” he continues. “This conformity effect has been previously demonstrated in an experiment with new food, but this is the first time we have observed it with social behavior”.

How social traditions are introduced and transmitted

The results show that groups not only have different social traditions, but those traditions may also be stable over time in ways that are likely socially mediated. The researchers suggest that these differences are transmitted through social learning, although they cannot rule out that there are also other differences in the environment.

Now that they know about the existence of these social traditions, they say they would like to know more about how they are introduced and transmitted. They are especially curious to know what role key people or leaders play in pressuring newcomers to follow them.

References (1) The social dynamics of vervet monkeys depends on the identity of the group. iScience.