Benton J. Underwood

Proactive inhibition in short-term retention of single items

Summary Three experiments were performed to determine the relationship between certain variables influencing proactive inhibition in long-term retention of lists of verbal items and the influence of these variables on short-term retention of single items. More particularly, retention of single items over 18 sec. should, if the laws of long-term retention are applied, decrease with number of previous items to which S has been exposed. In addition, amount of forgetting should be a direct joint function of number of previous items and length of the retention interval. In Exp. 1 each S was presented consonant syllables singly, with retention being measured after 3, 9, and 18 sec. Forgetting of the first item presented (T-1) was less than for the second (T-2) or third (T-3) item, but forgetting of the latter (T-2 vs. T-3) did not differ. On all three tests forgetting was directly related to length of retention interval, but no interaction was evident between number of previous items and length of retention interval. In Exp. 2 a higher degree of initial learning of the items was achieved. Forgetting increased directly as a function of number of previous items presented. The predicted interaction was indeterminate since retention was essentially 100% on T-1 for all retention intervals. Experiment 3 tested retention of six successive items over 3- and 18-sec. intervals. Retention after 3 sec. showed an initial drop and then a rise over the six tests, the rise suggesting a practice effect. Forgetting over 18 sec. increased directly from T-1 to T-6 and there was no indication that a constant amount of proactive interference had been reached. The interaction between length of retention interval and number of potential proactively interfering items was very evident. The results were interpreted to mean that proactive inhibition in short-term memory of single items follows the same laws as proactive inhibition in long-term memory of lists of items.

Critical issues in interference theory

Critical issues in the theoretical and experimental analysis of interference processes in retention are reviewed. The evolution of classical two-factor theory is traced, and the strengths and weaknesses of the contemporary version of this p6sition are examined. Recent critiques of Current interference theories by Martin (1971a) and Greeno, James, and Da Polito (1971) are reviewed and examind. New conceptualizations of interference proposed by these authors, which place major emphasis on retrieval dependencies and on the role of encoding and retrieval processes, are considered and evaluated.

Degree of learning and the measurement of forgetting

Summary This paper was directed toward problems involved in the measurement of forgetting uncontaminated by differences in degree of learning. More particularly, it was concerned with these measurements when some variable, such as a characteristic of the task, is being manipulated and when such a variable produces differences in rate of learning. If we are to assess properly the influences of these variables on retention, degree of learning must be equated, since degree of learning and retention are directly related. The two basic situations considered were those in which a constant number of learning trials was given and those in which learning was carried to a specified criterion of performance. The single-entry technique is appropriate only when a constant number of learning trials is used. When a criterion of performance is set for learning another procedure (multiple-entry projection) may be used. Although the mean predictions are fairly accurate by this method, predictions for individual Ss are not. In most studies of retention it seems most efficient to use a constant-trials procedure for learning. Finally, it was pointed out that some studies of short-term retention of single items have probably confounded effects of degree of learning on retention with the effects of variables producing differences in rate of learning the items.

Composition of episodic memory

Abstract : The primary purpose of the study was to examine the interrelationships among a number of episodic memory tasks, with a special interest in determining the correlations among various attributes of memory. The attributes investigated included imagery, associative, acoustic, temporal, affective, and frequency. The tasks were free recall, paired associates, serial, verbal-discrimination, classical recognition, and memory span, as well as less frequency used tasks. The 200 college-student subjects were tested for 10 sessions, and 28 different measures of episodic memory were obtained from the tasks. In addition, five measures of semantic memory were available. All scores were initially intercorrelated. Measures of episodic memory and semantic memory were generally unrelated.

Some correlates of item repetition in free-recall learning

The variables in six free-recall studies were the frequency of occurrence of a word within a single presentation of a long list of words, and the schedule of occurrences, either massed (MP) or distributed (DP). Recall of the DP words was much higher than that of the MP words. This was shown not to be due to rehearsal of other words during MP presentation. Degree of spacing of DP words had little influence on recall. The MP-DP difference also occurred in recognition memory. MP words presented with exactly the same frequency as DP words were judged to have occurred with far less frequency than the DP words, and it was concluded that the MP-DP difference was due to reception failure under MP which produced learning comparable to a lower actual frequency of presentation.

A breakdown of the total-time law in free-recall learning.

Five experiments are reported in which single-trial free recall followed various frequencies of repetition under massed (MP) and distributed (DP) schedules. All experiments showed the DP schedule to result in far better recall than the MP schedule, and the difference between MP and DP increased as the frequency of repetition increased. This was true for sentences, nonsense syllables, and words. Various activities inserted between successive words in the lists did not change the basic findings.

Further evidence on the MP-DP effect in free-recall learning

In Experiment 1, rate and frequency of presentation, concrete and abstract words, and imagery instructions were manipulated along with MP and DP schedules in a long free-recall list, presented for one trial. Large differences between MP and DP were found, but none of the other variables except frequency interacted with MP-DP. In Experiment 2, various forms of MP and DP patternings were used with all words presented four times. Recall was predictable by the number of distributed points within the patterns. In Experiment 3, S paced himself through a long list of words presented on slides. The usual MP-DP differences in recall were present, and parallel differences were observed in exposure times. The difference in MP and DP recall was greater than could be accounted for by differences in exposure time. All experiments showed recall to be related to the input position of the words.

The Representativeness of Rote Verbal Learning

Publisher Summary This chapter discusses certain phenomena derived from research on rote verbal learning in terms of their relevance to other areas of research on human learning when these phenomena appeared to have some counterpart in the other areas. It is a fact that in paired-associate learning, the associations that develop are to a large extent bidirectional. Not only the stimulus term elicits the response term, but also the response term elicits the stimulus term. While it is difficult to conceive of bidirectional associations for certain tasks in some areas of research, there is reason to believe that in concept formation, problem solving and creative thinking, bidirectional associations are the rule. The expectations are logical but it is difficult to find evidence for them. The so-called standardized tasks are very contrived and over the years have been simplified and refined. They are contrived to allow only a limited range of behavior to be exhibited and they are simplified to allow specific stimulus-response relationships to be derived and to be repeatable from one laboratory to another.

Perceived frequency of concrete and abstract words

Studies are reported which show that concrete and abstract words of equal objective frequency (based on available , word counts) are not perceived as being equal. The abstract word has greater perceived frequency than the concrete word. The judged variety of contexts in which a word appears correlates very highly with perceived frequency. The results have relevance to the design of learning studies in which concrete and abstract words are used. and also to the interpretation of such experiments.

An analysis of intralist similarity in verbal learning with experiments on conceptual similarity

An analysis was made of four subprocesses of verbal learning which may be expected to vary as intralist similarity (meaningful, formal, or conceptual) is manipulated in a PA list. Expectations were stated as to the role of each subprocess in over-all PA learning when similarity is manipulated among stimulus terms and among response terms independently. In the initial experiments, lists were constructed to eliminate two of the four subprocesses, leaving response learning and associative interference as the primary factors varying with conceptual similarity. The experiments showed that similarity among all stimulus terms was deleterious to learning while similarity among response terms had no effect on learning. These effects were independent of word frequency. Further experiments, devised to study response learning and associative learning independently, gave plausibility to the notion that with similarity obtaining among response terms, the positive effects of response learning balance the negative effects of associative interference for these materials. A final experiment varied the number of concepts within a list to examine the influence of a further hypothesized factor, S-R limitation. The overt-error data indicated the presence of this subprocess varying in extent as the number of concepts varied. However, the manner in which it contributed to over-all PA learning could not be ascertained.