Theideathatrepeatedexposuretoastimulusissuffi-cient to produce more positive attitudes toward the stimulus is an old idea, proposed by several psychologists (Fechner, 1876;James, 1890;Maslow, 1937). In 1968, Zajonc reviewed nearly a century of research supporting this idea and then presented the results of four experiments that provided strong support for it. In one experiment, college students viewed college yearbook photographs of men 1, 2, 5, 10, or 25 times and then rated how much they liked the men. A significant positive relation between frequency of exposure and liking emerged.Research has continued to demonstrate that familiar stimuli are preferred to unfamiliar stimuli. That is, presenting novel stimuli repeatedly without any reinforcement produces more positive attitudes toward those stimuli. This effect has been termed the mere exposure effect (Zajonc, 1968).