A substantial reason we evolved such large brains is to navigate our social world.

From The Social Leap by William von Hippel

It might strike you as odd that people are susceptible to these sorts of biases, but it’s worth remembering the evolutionary pressures that made us so smart in the first place. As the social brain hypothesis proposes, a substantial reason we evolved such large brains is to navigate our social world. In contrast to value in the physical world, value in the social world reflects objective reality only partially. If we decide that bell-bottoms are cool, then cool is what they are, and you’d better get yourself a pair or risk being a wallflower at the disco. A great deal of the value that exists in the social world is created by consensus rather than discovered in an objective sense.

If I can influence the consensus to move in a direction that favors me (whatever I’m doing is cool), then I’ll probably benefit even if my objective understanding of the world is biased. For this reason, it makes sense that our cognitive machinery evolved to be only partially constrained by objective reality, as the social consequences of our beliefs are often just as important as the objective consequences. Indeed, some researchers have argued that our minds evolved the ability to process logical arguments not so we could discover the true state of the world, but so we could convince others of the accuracy of our own self-serving beliefs.

In this sense, the social brain hypothesis suggests that the great discoveries of humankind are really just an evolutionary by-product of our ancestors’ efforts to persuade others of their dubious claims. In the words of my astronomer brother, “So NASA can thank all the self-serving liars of our evolutionary past for our ability to send robotic spacecraft throughout the solar system?” The answer to this question is a resounding yes, and it speaks to just how important sociality is in the evolution of our incredible cognitive abilities.