In this study, 48 third-grade children learned a successive, two-choice discrimination under one of three conditions: (1) immediate reinforcement (IM), (2) 10-second empty delay (ED), and (3) 10-second delay with the discriminative stimuli in view of S (FD). The performances of groups IM and FD were only marginally different, and were both superior to that of group ED. The reversal performances of the three groups did not differ significantly. Average latencies were significantly longer in groups FD and ED than in IM. It was condluded that in group FD a set to observe stimuli was established during delay which generalized to the preresponse interval and facilitated performance. (Author)