An examination into some variables said to affect serial learning

In each of three serial learning investigations, rats in a runway were given varying numbers of 0.045-g food pellets in a fixed order. Serial learning was indexed by faster running to larger than to smaller reward quantities. It has been suggested by Hulse (Animal Learning & Behavior, 1980,8, 689–690) and by Roitblat (Behavioral Brain Sciences, 1982,5, 353–371) that differences between two or more serial learning groups that have been obtained under one set of specified experimental conditions may be completely reversed or eliminated under another set of specified experimental conditions. In each of the three investigations reported here, we examined series that had been compared in previous investigations, employing, however, experimental conditions that, according to Hulse and to Roitblat, should produce results different from those obtained previously. In each of the three investigations reported here, the groups differed as they had previously. The findings obtained in this report suggest that none of the following variables is critical to the results obtained in serial learning investigation in the sense suggested by Hulse and Roitblat: the number of items contained in the series, the number of times the series is presented each day, the temporal interval elapsing between items, and the temporal interval elapsing between series presentations. The implications of the present findings for the rule-encoding view of Hulse and his coworkers and for the memory-discrimination learning view of Capaldi and his coworkers are examined.