Cooperation across social groups in bonobos

Amazing stuff!

"Chimpanzees and bonobos are our closest living relatives. So when anthropologists saw chimp groups wage wars with one another, they assumed that we humans, too, are innately aggressive creatures. But a closer look at our gentler bonobo cousins reveals that cooperation and kindness may be in our nature after all.

Although chimpanzees and bonobos look similar, they behave very differently. Instead of erupting with hostility, independent bonobo groups are often pleasant when they meet , even joining up for a time to travel, rest, and feed together, despite a lack of kinship. With chimpanzees, this kind of cooperation between unrelated individuals from different social groups basically never happens. So, it was long assumed that humans’ tendency to do this—a foundational behavior for our complex societies—was unique, a cultural feature stemming from our big, complex brains. These findings in bonobos challenge that idea, instead suggesting that the intergroup cooperation required for peaceful societies “can emerge in the absence of social norms or strong cultural dispositions,” the authors write.

“If the ancestors of modern humans treated members of other groups the same way that bonobos do, it might be the first step toward the evolution of multilevel societies,”  ..."

From the editor's summary and the abstract:

"Editor’s summary

Humans are very good at cooperating with others outside of our family, kin, and cultural groups. Although cooperation among individuals within groups is also common in other animals, doing so outside of such groups has rarely been observed. ... cooperative behaviors such as grooming and food sharing in bonobos and found that individuals that cooperated more within their own group were also more likely to cooperate with those in other groups (see the Perspective by Silk). Furthermore, such cooperation was neither rare nor opportunistic. Social openness in one of our closest relatives suggests that our cooperativeness may be older than we thought.

Abstract

Cooperation beyond familial and group boundaries is core to the functioning of human societies, yet its evolution remains unclear. To address this, we examined grooming, coalition, and food-sharing patterns in bonobos (Pan paniscus), one of our closest living relatives whose rare out-group tolerance facilitates interaction opportunities between groups. We show that, as in humans, positive assortment supports bonobo cooperation across borders. Bonobo cooperative attitudes toward in-group members informed their cooperative relationships with out-groups, in particular, forming connections with out-group individuals who also exhibited high cooperation tendencies. Our findings show that cooperation between unrelated individuals across groups without immediate payoff is not exclusive to humans and suggest that such cooperation can emerge in the absence of social norms or strong cultural dispositions."

Between-group cooperation in bonobos (no public access)

Cooperation across social borders in bonobos | Science (no public access)