Retroactive inhibition as a function of similarity of meaning in free-recall learning

Summary Retroactive inhibition in free-recall learning was measured under six degrees of meaningful similarity: zero, low, low-medium, medium, medium-high, and high. For each degree of similarity, an experimental and a control group of 20 Ss each learned a list of 20 unrelated adjectives through three cycles of alternate study and unpaced free recall. Immediately thereafter, the experimental group learned a second list of 20 adjectives, while the control group rested. Finally, a single recall trial was administered to both groups to measure first-list retention. The results have revealed a relationship which is at variance with the relationships observed in both serial and paired-associate learning but conforms to the curvilinear function earlier formulated by Skaggs and Robinson. Fresh arguments are offered in defence of the Skaggs-Robinson hypothesis.     

Retroactive interference in single-cue probability learning

Abstract.— When two single-cue probability learning tasks with different amounts of unpredictable variance were learned in succession. a low variance task interfered with the retention of a high variance task, but the opposite was not true. The effects were positive in that they enabled the subjects to reach a higher response consistency and, thus, a higher level of achievement. It was suggested that the subjects made use of the low variance task to reject incorrect hypotheses about the cue-criterion relation and that interference from an interpolated task occurs only when this task provides information which has functional value for the subject.     

Retroactive inhibition without intentional new learning: Some comment on the elicitation hypothesis

Two groups of subjects learned a list of paired-associates. Subsequently, an interpolated phase was introduced that did not require the acquisition of a new PA-list. The experimental group had to fulfill a number of little tasks with respect to the first terms of the previously learned list, whereas the control group did the task with words which were not on that list. In two experiments it was shown that when the retention of the learned associates was tested, the experimental group suffered more from forgetting than the control group. It is concluded that new learning is not a prerequisite in the induction of RI. The position of the elicitation hypothesis of Two Factor theory is critically discussed and the evocative disuse hypothesis is presented as an alternative conception with respect to the phenomenon of interference.     

Frequency estimation in verbal learning

A multicopy theory of frequency estimation and discrimination is applied to some data found in the literature on verbal learning. The main theoretical assumption adopted is that ‘relevant’ copies generated during study have to be discriminated from ‘irrelevant’ copies as are available in memory from other occasions than the study session proper. At retrieval, copies of either type are added and their sum determines the frequency estimates that are actually reported. A formalization of these ideas is presented and applied to Hinztman's (1969) and Underwood, Zimmerman, and Freund's (1971) data. Two specific models that emphasize either storage or retrieval of copy information are studied. The results show that the models provide a close approximation to the frequency discrimination data. With absolute frequency estimation, both the means and standard deviations of the judgements are predicted reasonably well. However, some reservations were dictated by the fact that, in one instance, the tails of the judgement distributions were not accounted for. The theory offers a theoretical framework for Underwood et al.'s method of cross-relating absolute frequency and forced choice judgements; the usefulness of two approaches to this problem is established. Also, possible extensions of the theory are noted.