How humans evolved high intelligence, required for complex collaborative activities, despite the various costs of having a big brain has long puzzled evolutionary biologists. While the human brain represents only about two percent of the body’s weight, it uses about 20 percent of the energy consumed. Other costs of having a large brain include a need for extended parental care due to a long growth period, difficulties giving birth to larger-headed babies, and some mental illnesses associated with brain complexity. So how did the human brain evolve to become so large and complex?
Another long-running question is how did humans evolve strong innate preferences for cooperative behavior, as cooperative behavior is vulnerable to exploitation by cheaters and “free-riders.” A free-rider doesn’t contribute or cooperate and thereby undermines the effectiveness of the group’s collaborative effort, something scientists call “the collective action problem.” Thus, collaborative behavior is expected to be rare, and indeed, in animals it is typically limited to close relatives. Humans, however, are a unique species where collaboration is widespread and not limited to relatives.
The theory cooked up here, using a mathematical model, is that warfare came first and was better than hunting for organizing collaborate behaviour. Despite the fact that an army travels on its stomach. The theory also explains altruism. Yes, that’s the thing. Always the need to explain away altruism.
By the way, “how did humans evolve strong innate preferences for cooperative behavior, as cooperative behavior is vulnerable to exploitation by cheaters and “free-riders”? Well, how about the fact that intelligence enables humans to detect this activity–which is one of the advantages of a large brain? Most humans just do not find it that difficult to spot the user and the cheat.
Note: Good idea to be cautious of theories about human behaviour that depend on mathematical models that ignore common sense observations. It’s easy to build something in and then, lo and behold, find it.
Humans are unique both in their cognitive abilities and in the extent of cooperation in large groups of unrelated individuals. How our species evolved high intelligence in spite of various costs of having a large brain is perplexing. Equally puzzling is how our ancestors managed to overcome the collective action problem and evolve strong innate preferences for cooperative behaviour. Here, I theoretically study the evolution of social-cognitive competencies as driven by selection emerging from the need to produce public goods in games against nature or in direct competition with other groups. I use collaborative ability in collective actions as a proxy for social-cognitive competencies. My results suggest that collaborative ability is more likely to evolve first by between-group conflicts and then later be utilized and improved in games against nature. If collaborative abilities remain low, the species is predicted to become genetically dimorphic with a small proportion of individuals contributing to public goods and the rest free-riding. Evolution of collaborative ability creates conditions for the subsequent evolution of collaborative communication and cultural learning. – Gavrilets S. Collective action and the collaborative brain. Open access Journal of the Royal Society Interface, 26 November 2014 DOI: 10.1098/rsif.2014.1067
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