Retroactive inhibition as a function of the conceptual structure of original and interpolated lists

Subjects learned either a hierarchically structured serial list of concept instances or a list made up of the same words but without structure. These two original lists were followed by one of four interpolated lists varying in number of hierarchical levels and consisting of new instances of the concepts which occurred in the original lists. Recall of the original structured list showed heavy retroactive inhibition, with the magnitude being independent of the number of conceptual levels in the interpolated lists. For the unstructured original list, retroactive inhibition decreased as the number of conceptual levels in the interpolated list increased. Some mechanisms believed involved in producing these outcomes were discussed.     

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.     

Revisiting an old issue: Retroactive interference as a function of the degree of original and interpolated learning

Prior research has generally shown that the greater the degree of original learning of a list, the greater the amount of retroactive interference that list suffers. In addition, greater learning of interpolated lists produces more retroactive interference. However, in prior research, the degree of learning has typically been confounded with the amount of retrieval practice on the list. Two free-recall experiments are reported in which subjects studied one original list and then 0, 1, 2, 3, or 4 interpolated lists. The degree of original and of interpolated learning was manipulated by varying exposure time. In Experiment 1, where the typical confounding of retrieval practice and degree of interpolated learning was present, greater interpolated learning induced greater retroactive interference, which is consistent with prior research. However, in Experiment 2, where the degree of interpolated learning was manipulated without concomitant variation in retrieval practice, retroactive interference was the same, whether the interpolated lists had been learned well or poorly. Therefore, greater interpolated learning does not increase the amount of retroactive interference. The results also show that the amount of retroactive interference does not depend on the degree of original learning, in agreement with other work on normal forgetting.     

Retroactive interference as a function of degree of interpolated study without overt retrieval practice

In two experiments, retroactive interference (RI) was examined under conditions designed to minimize retrieval-induced inhibition and output interference. In Experiment 1, the participants first learned a list of 10 person-location pairs, after which they viewed an interpolated list with the same person terms and different locations for one, four, or eight cycles. Learning was via a study-only method, so that the experimental participants did not perform instructed retrieval of the second list before a cued recall test that asked for List 1 locations only. The experimental participants in Experiment 2 received incidental learning instructions and then viewed a list of 20 unrelated words followed by another list presented either one or four times; the first two letters of each List 1 word were provided on the critical recall test. In both experiments, RI occurred and increased with degree of interpolation. The results suggest that RI does not require retrieval-induced inhibition.     

Retroactive inhibition as a function of the locus of categorized response sets

The effects which list-level taxonomic attributes should have upon retroactive inhibition (RI) producing mechanisms in both response-set interference theory (Postman & Stark, 1969) and Petrich’s (1975) retrieval model are discussed. A test of the theories was performed by manipulating the presence (1) or absence (0) of categorized response sets in both original learning (OL) and interpolated learning IIL), and comparing their predictions concerning the relative degree of RI expected in the four conditions (0-0, 0-1, 1-0, 1-1). In line with Petrich’s predictions, OL categorization significantly reduced RI, IL categorization significantly increased RI, and 0-1 produced significantly greater RI than 1-0. Moreover, the obtained ranking of the means for the experimental groups in degree of RI (0–1>0-0>1-0 ? 1-1) was in close agreement with the ranking predicted by Petrich’s (1975) model. The results provide support for Petrich’s (1975) retrieval model and pose explanatory problems for response-set interference theory (Postman & Stark, 1969).     

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.     

Buildup of proactive inhibition as a function of temporal spacing and adult age

Glenberg's theory of temporal distinctiveness (Glenberg, 1987; Glenberg & Swanson, 1986) was used to examine whether the buildup of proactive inhibition (PI) may be interpreted as an overloading of temporal retrieval cues. The Brown-Peterson task was selected on the basis of the assumption that successful performance on such a task requires the use of a recency rule where the subject must use temporal cues to retrieve the contents of the most recent study list. Two variables were manipulated that were presumed to affect the utilization of temporal cues: length of intertrial interval (ITI) (0 or 90 s) and adult age (young or elderly). Glenberg's theory suggests that temporal spacing improves memory by enhancing the distinctiveness of temporal retrieval cues. Thus, it was predicted that PI buildup should be less in the 90-s condition than in the 0-s condition. Assuming that older adults are more sensitive to the overloading of temporal cues, it was anticipated that older adults would experience a greater buildup of PI than younger adults at the 0-s condition. Results showed that although PI buildup varied with length of ITI, it did not vary with adult age. Analysis of delayed measures of recall, recognition, and temporal memory suggested that a retrieval interpretation based on Glenberg's theory is insufficient as an explanation of the current results; encoding difficulties also appear to contribute to the buildup of PI.     

Effect of interpolated temporal activity on temporal short-term memory

The purpose of this research was to determine the retroactive interference effects of a single interpolated task (i.e., one temporal duration) on the retention of a criterion duration. This research is of interest because the mnemonic structure of temporal information of different durations is uncertain. Previous research has indicated that there might be a difference in structure for durations of 1 and 4 sec., although the results are inconsistent. Thus, two criterion durations of 1 and 4 sec. and five interpolated durations (i.e., 60%, 80%, 100%, 120%, and 140% of the duration of the criterion) were utilized under the method of reproduction. In addition, subjects were instructed to use either a counting strategy or none (referred to as conscious time estimation) to facilitate the retention of the temporal information. Recall was less variable when using a counting strategy than not and when estimating 1 sec. than 4 sec. However, there was no effect of interpolated activity when comparing performance across different interpolated conditions (no interpolated activity). Apparently, one interpolated duration is not sufficient to produce structural interference with a single criterion duration.