INCREMENTAL AND UNITARY ASPECTS OF PAIRED-ASSOCIATE LEARNING AND RETENTION

Summary.-Paired-associate learning with item replacement displayed unitary (all-or-none) properties of sequential response dependencies and equivalence of new items to retained items previously responded to incorrectly. The recent revolution in experimental design and techniques of analysis appropriate for revealing the fundamental aspect of learning as either incremental or unitary was initiated by Voeks (1954), developed by Kimble, et al. (1955), and culminated by Esres (1960). A veteran design of this revolution has been the comparison of normal paired-associate learning and retention procedures with those where missed items (Rock, 1957) or correct items (Krlstofferson, 1961) are subsequently replaced by new items. If learning were unitary, attenuation of learning should not occur when incorrecc items were replaced (a negative result that Rock did find); potentiation of learning should not occur with repeated incorrect items when correct irems were rejected (a potentiation result that Kristofferson, honever, did find). Such designs pose a problem: when irems are rejected on the basis of Ss responses, any number of variables, for instance item "difficulty," may be confounded with the difference in reinforcement history berween retained and new items. The present srudy attempts to minimize such confounding by eliminating items independently of S's responses. By utilizing a miniamre design and the sensitive individual sequential analysis of the sort innovated by Estes (1960), comparisons can be made berween previously correct items, previously incorrect items, and new items, for evidence of unitary or incremental learning and retention. In this experiment, consonant-vowel-consonant nonsense syllables served as stimuli and numbers as responses. The presentation of eight such pairs was a reinforced trial; the presentation of the eight stimuli was a test trial. Each S received a reinforced trial, a test trial, another reinforced trial, and then three test trials. For 32 Ss, one item on the second reinforced trial (Trial 3) was replaced with a new item. The rejected item whose place it took was chosen at random, independently of the correctness of the response to it on the first test trial. For 27 Ss there were four such replacements, and for 28 Ss there were seven such replacements. The proportions for eac~ possible sequence of correct and incorrecc responses per item on the last three test tricls are given separately in Table 1 for stimuli responded to correctly on the first test trial (102 items), for stimuli responded to incorrectly on the first test trial (258 items), and for stimuli from items new on che second reinforced trial (336 items). There were no differences on the basis of the number of items replaced. Theoretical proportions based on simple incremental and unitary stochastic models are also given. A main feature of these data is that for items missed on the first test trial, the sum of the proportions for all sequences with correct responses on the first of the last three rest trials (.403) was very near identical to that for new items (.387), as a unitary 'The cooperation of the faculty, and of the students in the learning laboratory class who served as Es, and of che introductory psychology students who served as Ss at San Diego State College is gratefully acknowledged.