Human beings are primates, and primates are political animals. Our brains are therefore designed not just to hunt and gather, but also to get ahead socially, often by devious means.
But while we may be self-interested schemers, we benefit by pretending otherwise. The less we know about our own ugly motives, the better. And thus we don’t like to talk — or even think — about the extent of our selfishness. This is “the elephant in the brain,” an introspective blind spot that makes it hard to think clearly about ourselves and the explanations for our behavior.