What’s So Funny? The Science Of Why We Laugh
Wilson is a major proponent of group selection, an evolutionary theory based on the idea that in social species like ours, natural selection favors characteristics that foster the survival of the group, not just of individuals
Wilson and Gervais applied the concept of group selection to two different types of human laughter. Laughter by group members in response to what Wilson and Gervais call protohumor—nonserious violations of social norms—was a reliable indicator of such relaxed, safe times and paved the way to playful emotions. Over the years additional theories have proposed different explanations for humor’s role in evolution, suggesting that humor and laughter could play a part in the selection of sexual partners and the damping of aggression and conflict.
Source: www.scientificamerican.com