Human beings have an evolutionary history, and deception is commonplace in the animal world because it confers evolutionary advantage. There’s good reason to believe we’re not so different, other than the fact that humans are ultra-social creatures. In ancestral and evolutionary terms, being part of a successful social group was every bit as essential as food and water. So deception among humans evolved from group conflicts. That’s the thesis of a recent paper called “The Evolutionary Psychology of Conflict and the Functions of Falsehood” by the Danish political scientists Michael Bang Petersen and Mathias Osmundsen and American anthropologist John Tooby.
“We can signal loyalty to a group by having a certain set of beliefs…. First of all, it should be a belief that other people are not likely to have, because if everyone has this belief, then it’s not a very good signal of group loyalty. It needs to be something that other people in other groups do not have. The basic logic at work here is that anyone can believe the truth, but only loyal members of the group can believe something that is blatantly false,” [said Petersen.]