Laugh and Laughter as Adaptation in Human Being

Abstract

In the process of human evolution, the biggest adaptive problems have been how to maintain a group and how to rise in rank in a group hierarchy. If an adaptive problem is solved, the probability the solver will survive and success in reproduction rises. Laugh and laughter is discussed in the frame that it has been used to solve the adaptive problem in this chapter. The trigger of laughter is the cognition of a discrepancy. The discrepancy is the difference between what is expected and the actual state. A discrepancy cannot be serious to cause laugh and laughter. If it is implicitly expected to be resolved, then it is likely to arise a laughter with positive feeling. When laughter is shared by some people, it functions to link them with friendly relationship. On the other hand, the laughter becomes derisive (ridicule) when the discrepancy is between a social norm and an actual behavior. The ridicule functions to one's supremacy over the target individual. This function has been adaptive in the society of dominance hierarchy.