The human brain's willingness to collaborate with others was triggered by prehistoric conflict, a new study reveals.
In the new study at the University of Tennessee, researchers developed a mathematical model that offers answers to how humans evolved high intelligence, required for complex collaborative activities, despite the various costs of having a big brain and how did humans evolve strong innate preferences for cooperative behavior, as cooperative behavior is vulnerable to exploitation by cheaters and "free-riders."
The research, which points to the types of collective actions that are most effective at hastening collaboration, shows that intelligence and cooperative behavior can co-evolve to solve the problem of collective action in groups and also, to overcome the costs of having a large brain.
According to the model, collaborative ability evolves easiest if there is direct conflict or warfare between groups, what lead author Sergey Gavrilets calls "us vs. them" activities and in contrast, collective activities, such as defending against predators or hunting for food, which Gavrilets calls "us vs. nature" activities, are much less likely to result in a significant increase in collaborative abilities.
The study also predicts that if high collaborative ability cannot evolve, perhaps for example because the costs of having a big brain are too high, the species will harbor a small proportion of individuals with a genetic predisposition to perform individually-costly but group-beneficial acts.
In addition, the model challenges influential theories on when large-game hunting and within-group coalitions first appeared in humans. Some scientists say that within-group coalitions and collaborative hunting came first and then subsequently created conditions for the evolution of collaboration in between-group conflicts.
The study is published in the Journal of Royal Society Interface.