Relief theory maintains that laughter is a homeostatic mechanism by which psychological tension is reduced.Humor may thus for example serve to facilitate relief of the tension caused by one’s fears.Laughter and mirth, according to relief theory, result from this release of nervous energy. Humor, according to relief theory, is used mainly to overcome sociocultural inhibitions and reveal suppressed desires. It is believed that this is the reason we laugh whilst being tickled, due to a buildup of tension as the tickler “strikes”. According to Herbert Spencer, laughter is an “economical phenomenon” whose function is to release “psychic energy” that had been wrongly mobilized by incorrect or false expectations. The latter point of view was supported also by Sigmund Freud.