Scientists have spent years trying to identify the factor that leads humans to act selflessly on many occasions.
We were known to share this trend with some species of small primates of the Callitrichidae family (tamarins and marmosets), which live in Central and South America.
Some experts had suggested from this data that the cooperative and solidary care by the youngest own of these monkeys would be the origin of the behavior that impels us to spontaneously help others. However, the role that other primate species could play was not clear, as there were no comparative studies to date.
Now, a team of Swiss, German, Austrian, Italian and British researchers, led by the anthropologist Judith Burkart, from the University of Zurich, have developed a new systematic method that analyzes spontaneous altruistic behavior in a standardized way and that can be applied to many other ape species for their study, published in Nature Communications .
It was a question of checking with a device moved by a lever that supplies food, if the individuals of a specific species of primates were willing to provide food to other members of the group, even if that led them to deprive themselves of part of the ranch.
The test was done with 24 social groups of 15 different species of monkeys . They also analyzed the altruistic acts of children between 4 and 7 years old. The researchers found that the tendency to help and provide for others varied remarkably from one species to another. According to Burkart, “humans and Callitrichidae monkeys have a very altruistic behavior and are almost always willing to invite other companions from the group.
On the other hand, chimpanzees, who are our closest relatives, only do it sporadically ”. Similarly, many other monkeys, such as capuchins and macaques, barely feed their peers, despite their considerable cognitive abilities.
Until now, most experts assumed that spontaneous altruistic behavior in primates responded to factors that they shared with humans: advanced cognitive abilities, large brains, high social tolerance, search for food in common, and strong social or partner ties. But according to Burkart’s study, none of these factors necessarily implies that a species will have altruistic behaviors.
Instead there is an important factor that sets humans apart from the great apes in this matter: “spontaneous altruistic behavior occurs exclusively in species in which the care of the young is not only in charge of their mothers , but also of older siblings, parents, grandparents, uncles, and other members of the group. It is what is called cooperative feeding ”.
From the study it is deduced that cooperative behavior favored the evolution of our exceptional cognitive abilities . In their developmental phase, children gradually build their skills from an extensive network of selfless help from their parents and other adults. Researchers believe that is what steered our ancestors toward cognitive excellence.
