One hundred twenty-eight preschool boys were subjects in a 4x2x2 factorial design to investigate the change in reinforcer efficacy as a function of prior stimulus exposure. The factors were: (1) amount of repetition, 5, 25, 45, or 65; (2) reinforcer, good or bell; and (3) satiator, good or bell. Two additional groups were run as control groups to determine the effectiveness of good and bell in the absence of satiation treatment. Following the experimental treatment, Ss were given 50 learning and 25 extinction trials on a fixed color-position discrimination learning task. Support for stimulus satiation and satiation generalization was found on both learning and extinction data. The obtained functional relationships were generally curvilinear. (Author)