Abstract
2 groups of albino rats received the same schedule of reward and nonreward (NNNRN), the same magnitude of reward, the same intertrial interval but differed in terms of odor conditions. Each S in a partial reinforcement, within-Ss group received all 5 daily trials before the second S received its first daily trial, etc. Tor Ss in a between-Ss, odor group, 4 other Ss received a given trial before the first S received its second trial, etc. Thus, the only difference between these groups was whether an S followed itself or other Ss. The results showed that during acquisition there was no difference in goal approach rate between the groups, but during extinction, the group of Ss receiving all trials before others were tested extinguished significantly faster than the group of Ss run 1 trial at a time in the start, run, and goal segments of the runway. The study points to important methodological considerations for odor control.