Cooperation leads to intelligence.
In fact, researchers believe that intelligence in our species and others — correlated with the size of a brain’s neural network — may have been an adaptation for tool use, for social learning, and for the accumulation of culture. Intelligence might also be the result of sexual selection.
The findings, published in the latest Proceedings of the Royal Society B, could help to explain why humans, dolphins, elephants and other clever animals are so brainy.
The idea that complex social interactions drive the evolution of intelligence has been around since the 1970’s. The problem with related studies has been how to disentangle what factors actually fuel intelligence and what were subsequent consequences of it.
"Because experimental evolution of vertebrate brains is obviously impossible, we thought artificial intelligence would be the best way to evaluate the plausibility of the hypothesis," lead author Luke McNally told Discovery News.
The process might even be fueling the evolution of ever more intelligent individuals.
“It is conceivable that, with the rise of global networking, the demands of keeping track of an ever-growing number of social interactions may select for greater social intellect, but we’ll have to wait and see!” McNally said.
McNally, a member of Trinity College Dublin’s Theoretical Ecology Research Group, conducted the study with colleagues Sam Brown and Andrew Jackson. They created digital organisms that electronically evolved "brains" in order to succeed in social games where they could either cooperate or cheat on their opponent.
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Each individual’s fitness, based on the game outcomes, was calculated per round, with certain individuals selected to reproduce. Newly produced "offspring" underwent mutations, similar to what happens in real life. Generations also died. The researchers ran this genetic algorithm until 50,000 generations were reached.
The researchers found that the digital organisms typically started to evolve more complex brains when their societies began to develop cooperation. The results therefore support the idea that cooperation helped to drive the evolution of intelligence in at least certain species.
"The transitions to cooperative societies from uncooperative ones select for intelligence because of the constant risk of being exploited by uncooperative individuals," McNally explained. "This requires memory of past interactions and use of this memory to make decisions."
He added, however, that the process creates opportunities for "naïve individuals who always cooperate to invade the population. This can further create opportunities both for 'mean' individuals to invade and individuals that recognize and exploit the naïve competitors."
He is also quick to add that intelligence facilitates cooperation, but does not inevitably lead to it. Some of the most cooperative species are bacteria and certain social insects such as wasps, bees and ants. While these organisms are very successful, they are small and not exactly known for their big brains.
A Machiavellian arms race, where greater intelligence and complex strategies select for further intelligence and complexity, evolved in humans and other animals which may have also been affected by other factors, the researchers concluded.
Sarah Brosnan, an assistant professor of psychology and neuroscience at Georgia State University, told Discovery News that the new study “is a really interesting addition to the literature” on what helps to explain the evolution of intelligence.
“This is one of the first models showing that selection for efficient cooperative decision making alone can influence the evolution of intelligence, so it provides a really nice proof of concept for the social intelligence hypothesis,” she said. “This could potentially explain the large brain sizes seen in several highly cooperative species, including humans.”
Robin Dunbar, director of the RSA’s Institute of Cognitive and Evolutionary Anthropology in the School of Anthropology, said that it appears “mutualism as opposed to simple altruism is critical to primate, including human, sociality,” suggesting “that it is this kind of social cooperation that has been critical in terms of selection for large brains.”
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