THE EFFECT OF MULTIPLE S-DELTA PERIODS ON RESPONDING ON A FIXED-INTERVAL SCHEDULE. II. IN A PRIMATE.

A squirrel monkey was subjected to a fixed-interval pattern of reinforcement. During the course of each interval a bright white light was repeatedly presented. In the presence of the white light, a response was never immediately followed by food; the white light thus functioned as S(Delta). Responding was interrupted during the S(Delta) periods, but in the squirrel monkey as in the pigeon, these interruptions did not destroy the characteristic scalloped pattern of the cumulatively recorded responding through each interval.