Political Animals and the Social Intelligence Hypothesis

Aristotle saw a connection between social complexity and animal intelligence. He noted that the more intelligent animals tended to be those with the most intensive and prolonged parental care, because the complexity of the social interaction between parents and offspring requires high intelligence. Similarly, he identified the political animals--those who cooperate for some common work or function--as highly intelligent. Human beings are by nature more political than these other political animals, because of the uniquely human capacity for speech (logos). Human beings are the most political animals, it seems, because through speech human beings cooperate for common ends in ways that are more complex, more flexible, and more extensive than is possible for other political animals.

This Aristotelian idea of the connection between sociality and intelligence seems to resemble the "social intelligence hypothesis" that has become popular with many evolutionary theorists today. This hypothesis explains the evolution of complex cognition and enlarged brains as an adaptive response to the complexity of social life, so that we can explain the greater intelligence if primates, for example, as an evolutionary adaptation to the greater social complexity of primate life.

Although this idea is supported by a lot of evidence and reasoning, a few researchers are beginning to question its adequacy. I was recently reminded of this in reading a paper by one of my graduate students--Jennifer Soss--who argues that the social intelligence hypothesis cannot explain the differences between rhesus macaques and chimpanzees. Although chimps are superior to monkeys in cognitive abilities, and although chimp brains are larger and more complex than monkey brains, it's not clear that chimp social life and social cognition is more complex than that of monkeys. So there must be other factors to explain the evolution of higher intelligence in chimps.

A good survey of this argument is in an article by Kay Holekamp--"Questioning the Social Intelligence Hypothesis". Holekamp is a zoologist specializing in the study of spotted hyenas. She argues that social carnivores like spotted hyenas are remarkably similar in their social complexity to primates, although primates are clearly superior in some higher cognitive functions, which suggests that the adaptation of intelligence for social complexity can't be the whole story. She accepts the social intelligence hypothesis as well-supported. But her claim is that there must be other factors interacting with social complexity to explain the evolution of high intelligence.

Actually, Holekamp's argument takes us back to Aristotle. Because while he emphasized the importance of social complexity as connected to intelligence, he also stressed the importance of intelligence in allowing animals to better manipulate their nonsocial environment in devising tools and strategies for gathering food and protecting against predators.

Although we don't see any evolutionary account of the ultimate origins of intelligence in Aristotle's biological writings, we do so an understanding of how intelligence must be explained biologically as a natural adaptation to the lives of animals who need the cognitive tools for living in complex social and physical environments.