Four groups of 15 Ss each acquired conditioned eyelid responses to a 1024-cps tonal stimulus delivered at 40 db above threshold. While the arithmetic mean intensity of the reinforcing airpuff was held constant, reinforcement was varied about the mean in distributions which varied in shape. Seventy acquisition trials were given. Distribution shape differences failed to produce differences in the form of acquisition curves or in the total number of anticipatory responses during acquisition.
