THE ADAPTIVE VALUE OF HUMOR AND LAUGHTER

Most explanations for humor neglect important types of humor, such as tickling and word play; or raise difficult evolutionary theoretical pr oblems, such as group selection, dubious fitness benefits, and excessi ve complexity of design; or ignore the data on humor and laughter. The present theory was based on the following observations. Tickling enta ils a mock attack at vulnerable body spots, and may provide youngsters with practice in defending themselves. The child's laughter is pleasa nt and encourages the tickler to persist. Similarly, juvenile primates including children encourage roughhousing by laughter and other emoti onal expressions. We also laugh at humorous content that provides stri king counter-examples (incongruities), as in word play, or that inform s us about fitness-relevant topics such as sexual, aggressive, and soc ial poise scenarios. The present theory is that the pleasure of humor motivates us to seek out poignant, fitness-enhancing input of this sor t. Laughter evolved to allow us to continue to receive amusement. Laug hter is a pleasant social signal that prompts the humorist to persist in providing this edifying stimulation. In response to true wit, laugh ter conveys appreciation and gratitude-an intention to reciprocate for having received a stimulating idea. Thus, humor benerits both humoris t and laughter. This theory and others are evaluated in the light of e volutionary principles and relevant data.