Like humans, marmosets (monkeys with Einstein-like ear monkeys from Brazil) listen to conversations among others and prefer to approach people who see positively, according to a study published in the journal Scientific advances showed Wednesday.
Although behavioral research has accumulated knowledge about the social life of primates, it has tended to lack reliable ways to determine an individual’s “inner perspective” or the inner workings of their mind.
Titis are an ideal species to study because of their close-knit social structure: they live in highly cooperative groups of about 15 family members, with the entire extensive clan responsible for raising children.
How do they decide who is reliable and who is not?
A team led by Rahel Brugger at the University of Zurich (UZH) presented 21 captives of captive-born adults with recordings of a hidden speaker of an adult of the opposite sex making food tender calls or aggressive chat calls in response to babies requesting request.
As a control, they also played titis calls made by a single individual.
Scientists pointed the infrared cameras at the faces of the tits to record nasal temperatures, looking for drops that indicated the monkeys were alert and engaged.
In the tests it was found that the puppies only answered combined and not individual calls, indicating that they understood when real conversations were taking place.
After touching the recordings, the team let the titties into a room full of toys and a mirror.
The titis do not recognize his own reflection and therefore believed that he represented the monkey making the recorded call.
The researchers found that puppies generally preferred to approach when recordings indicated that the individual was helpful.
“This study adds to the growing evidence that many animals are not only passive observers of third-party interactions, but also interpret them,” said Judith Burkart, lead author of the work and professor of anthropology at UZH.
The team plans to use this temperature mapping approach for future research, such as the origin of morale.
© France-Presse Agency