Affiliation:
1. Southern Methodist University
Abstract
3 groups of 10 rats were trained for 6 trials per day for 34 days on one of the following reward schedules: 2 pellets on odd trials and 4 pellets on even trials (Group 2–4), 2 pellets on odd trials and 8 pellets on even trials (Group 2–8), and 2 pellets on odd trials and 16 pellets on even trials (Group 2–16). Following acquisition, extinction training was given at 6 trials per day for 6 days. In acquisition, the 2–16 group learned to run fast on the even trials and slow on the odd trials (patterned running). In extinction, Groups 2–4 and 2–16 ran similarly but both ran significantly more slowly than the 2–8 group. These results were interpreted as supporting the hypothesis that the increased resistance to extinction usually provided by large variation in reward depends upon the absence of patterned running in acquisition.