Researchers have been working to discover what makes people behave so selflessly in certain situations.
Humans share this trait with a small Latin American primate in the family Callitrichidae, suggesting spontaneous helping behavior is linked to cooperative caring for young, the University of Zurich reported.
Researchers looked at whether or not individuals from particular primate species would provide other group members with a treat, even if it meant not getting one themselves. The team performed their study on 24 groups consisting of 15 different primate species; they also looked at human children between the ages of four and seven.
"Humans and callitrichid monkeys acted highly altruistically and almost always produced the treats for the other group members. Chimpanzees, one of our closest relatives, however, only did so sporadically," said Judith Burkart from the University of Zurich.
The team found most primate species, including capuchins and macaques, pulled the lever only to give another group member food.
In the past researchers have assumed spontaneous altruistic behavior in primates was linked to things they shared with humans such as "advanced cognitive skills, large brains, high social tolerance, collective foraging or the presence of pair bonds or other strong social bonds," the University of Zurich reported. This new study suggests another reason.
"Spontaneous, altruistic behavior is exclusively found among species where the young are not only cared for by the mother, but also other group members such as siblings, fathers, grandmothers, aunts and uncles." Burkart said.
The phenomenon could also be affected by upbringing; children are constantly constructing their cognitive skills off what inputs they receive from caring parents and other helpers. This mode of caring was most likely what made our ancestors so successful, meaning the study may have identified the root of what made us human.
"When our hominin ancestors began to raise their offspring cooperatively, they laid the foundation for both our altruism and our exceptional cognition," Burkart said.
The results of the study were published recently in Nature Communications.
