Comparison of output order in free recall

Two measures of output order in free recall were examined and shown to vary with characteristics of recall unrelated to output order. The output location of a subset of items in recall, using the standard recall rank measure and the “observed minus expected” score, varied both with number of items in the subset and total number of items recalled. A new measure of output order (the relative index of priority or RIP score) was proposed that is invariant with these characteristics of recall, providing an uncontaminated empirical index of the output location of a subset of items in the recall sequence.     

Hypermnesia in free recall and cued recall

In three experiments, categorized lists and both free recall and cued recall tests were used to examine hypermnesia. In Experiment 1, materials were drawn from obvious and nonobvious categories in an attempt to vary the amount of relational processing at encoding. The study materials in Experiment 2 consisted of a long word list that comprised several exemplars from each of a number of common categories. In Experiment 3, a single exemplar was drawn from each of 45 categories. In each experiment, similar magnitudes of hypermnesia were obtained on free and cued recall tests. Examination of the specific items recalled across tests indicated that similar processes underlie the hypermnesic effect for both test conditions. Implications of the results for extant accounts of the hypermnesic effect are discussed. It is concluded that the dynamics of retrieval processes change in a systematic fashion across repeated tests and the retention interval following study and that an adequate account of the nature of these changes in retrieval dynamics is essential to our understanding of hypermnesia and related phenomena.     

A stochastic model for free recall

A statistical model for verbal learning is presented and tested against experimental data. The model describes a Markov process with a realizable absorbing state, allowing complete learning on some finite trial as well as imperfect retention prior to this trial.This work was carried out while the author was at Lincoln Laboratory, Massachusetts Institute of Technology.Operated with support from the U. S. Army, Navy, and Air Force.     

Analyzing the dynamics of free recall: An integrative review of the empirical literature

Relatively few experiments have measured the time course of free recall from episodic or semantic memory. Of those that have, most report that cumulative recall is a negatively accelerated exponential (or hyperbolic) function that is characterized by two properties: asymptotic recall and rate of approach to asymptote. The most common measure of free recall performance (viz., the number of items recalled) provides a reasonably good estimate of asymptotic recall if a relatively long recall period is used (which is rare), but the effect of experimental manipulations on the rate of approach to asymptote cannot be determined without timing when recall responses occur. The research reviewed herein suggests that the rate of approach to asymptote may offer an estimate of the breadth of search through long-term memory. The search in question, unlike most of those investigated in the memory literature, is unique in that it requires minutes rather than milliseconds to complete.     

Understanding the dynamics of correct and error responses in free recall: Evidence from externalized free recall

The dynamics of correct and error responses in a variant of delayed free recall were examined in the present study. In the externalized free recall paradigm, participants were presented with lists of words and were instructed to subsequently recall not only the words that they could remember from the most recently presented list, but also any other words that came to mind during the recall period. Externalized free recall is useful for elucidating both sampling and postretrieval editing processes, thereby yielding more accurate estimates of the total number of error responses, which are typically sampled and subsequently edited during free recall. The results indicated that the participants generally sampled correct items early in the recall period and then transitioned to sampling more erroneous responses. Furthermore, the participants generally terminated their search after sampling too many errors. An examination of editing processes suggested that the participants were quite good at identifying errors, but this varied systematically on the basis of a number of factors. The results from the present study are framed in terms of generate-edit models of free recall.     

A developmental study of attribute encoding in free recall

In two studies, subjects from second-grade, sixth-grade, and college were presented lists of unrelated words for single-trial free recall. Embedded in the list were critical items that were either semantically or phonemically related or else were completely unrelated. The sets of related items were either massed or distributed in the longer list. For second-graders, recall of Phonemic words was better than recall of Semantic words while the reverse was true for sixth-graders. Recall of Semantic distributed words by second-graders and of Phonemic distributed words by sixth-graders did not differ from recall of unrelated words. College students recalled Phonemic and Semantic words equally well and all related words better than unrelated words. Developmental trends were seen in the salience of particular attributes and in the utilization of low salient attributes.     

Associative factors in free recall

An experiment on the free recall of 18-word lists is reported in which variations were made in associative frequency, word frequency and the number, and therefore size, of the presented groups. Recall efficiency was positively related to increasing associative frequency and larger presented group size. Measures of clustering were obtained along with subjects' own reports on the associative labels helpful to them in organizing their recall. A two-level storage model is proposed to account for the results.     

Recall termination in free recall

Although much is known about the dynamics of memory search in the free recall task, relatively little is known about the factors related to recall termination. Reanalyzing individual trial data from 14 prior studies (1,079 participants in 28,015 trials) and defining termination as occurring when a final response is followed by a long nonresponse interval, we observed that termination probability increased throughout the recall period and that retrieval was more likely to terminate following an error than following a correct response. Among errors, termination probability was higher following prior-list intrusions and repetitions than following extralist intrusions. To verify that this pattern of results can be seen in a single study, we report a new experiment in which 80 participants contributed recall data from a total of 9,122 trials. This experiment replicated the pattern observed in the aggregate analysis of the prior studies.     

Organisational processes in free recall

In a free recall task, homogeneity of semantic reference and strong associative connections facilitated the recall after a twenty second filled interval of lists of 18 words. Facilitation in the recall of lists consisting of three sets of six related words when compared with six sets of three related words was also obtained. The organisation present in the recalled sequences is reported using various clustering measures and differences between the measures are indicated and discussed. Difficulties in the use of such measures in evaluating an hypothesis about the relationship between recall and organisation are illustrated and the general theoretical issue of selecting between alternative measures of organisation is considered.     

A comparative analysis of serial and free recall

Multitrial free and serial recall tasks differ both in recall instruction and in presentation order across trials. Waugh (1961) compared these paradigms with an intermediate condition: free recall with constant presentation order. She concluded that differences between free and serial recall were due only to recall instructions, and not to presentation order. The present study reevaluated the relation between free and serial recall, using Waugh's three conditions. By examining recall transitions and the organization of information retained across trials, we conclude that presentation order is an important factor, causing participants to exhibit the same temporal associations in serial recall and in free recall with constant presentation order.     

Memory for previous recall: a comparison of free and cued recall

Case studies of individuals who claimed to have recovered previously repressed memories of abuse during situations that involved memory cueing revealed that some individuals had discussed abuse with others during an earlier time period. Termed the ‘forgot‐it‐all‐along’ effect, this phenomenon has legal implications for statutes of limitations. Two experiments provide evidence for differences between free recall and more directed (recognition or cued recall) test conditions in the accuracy of memories for previous recall. Participants more often erred by claiming they had not previously remembered recognized (Experiment 1) or cued (Experiment 2) sentences than freely recalled sentences, and this difference was obtained even when the number of remembered sentences was equivalent across conditions (Experiment 2). These studies document that memory for previous recollection is less accurate for cued memories even when remembered events do not produce feelings of shock or surprise. Copyright © 2002 John Wiley & Sons, Ltd.     

A developmental study of relations between free recall, cued recall, and recall of incidental material

Six-, 9-, 17–19-, 45–55-, and 65-year-old subjects were shown 16 slides depicting one colored object and two uncolored context objects in a common setting, the task being to learn the names of the colored objects. Free and cued recall of both colored and context items were tested, the context objects being used as retrieval cues for the colored ones, and vice versa. The relative superiority of cued recall to free recall decreased regularly with increasing age. In the oldest subjects the level of free recall of TBR-objects was still fairly high, the level of recall of context objects being very low. The results support the hypothesis that adults encode nominally irrelevant context materials to a decreasing extent with increasing age, and that memory traces of young people in this sense are "richer", i.e., contain a greater number/variety of potential retrieval cues, than those of the elderly.     

A recency-based account of the primacy effect in free recall

Seven experiments investigated the role of rehearsal in free recall to determine whether accounts of recency effects based on the ratio rule could be extended to provide an account of primacy effects based on the number, distribution, and recency of the rehearsals of the study items. Primacy items were rehearsed more often and further toward the end of the list than middle items, particularly with a slow presentation rate (Experiment 1) and with high-frequency words (Experiment 2). Recency, but not primacy, was reduced by a filled delay (Experiment 3), although significant recency survived a filled retention interval when a fixed-rehearsal strategy was used (Experiment 4). Experimenter-presented schedules of rehearsals resulted in similar serial position curves to those observed with participant-generated rehearsals (Experiment 5) and were used to confirm the main findings in Experiments 6 and 7.     

A context-based theory of recency and contiguity in free recall

The authors present a new model of free recall on the basis of M. W. Howard and M. J. Kahana's temporal context model and M. Usher and J. L. McClelland's leaky-accumulator decision model. In this model, contextual drift gives rise to both short-term and long-term recency effects, and contextual retrieval gives rise to short-term and long-term contiguity effects. Recall decisions are controlled by a race between competitive leaky accumulators. The model captures the dynamics of immediate, delayed, and continual distractor free recall, demonstrating that dissociations between short- and long-term recency can naturally arise from a model in which an internal contextual state is used as the sole cue for retrieval across time scales.     

Short-term temporal changes in free recall

An experimental study of short-term memory for lists of familiar English words is reported. Lists of 10, 20, and 30 unrelated words were presented at a 1-sec. rate. Retention was measured by free recall after intervals of 0, 15 and 30 sec. A counting task was used to prevent rehearsal during the retention interval. The absolute level of recall increased with length of list whereas the percentages retained showed the reverse trend. The recall scores decreased steadily as a function of retention interval, with the rates of forgetting comparable for the three lengths of list. The decline in the amount recalled was due in large measure to the loss of the terminal items in the list. Consequently, the pronounced recency effect present on the immediate test of recall was progressively reduced as a function of time. By contrast retention of the initial part of the list was relatively stable. These variations in rate of forgetting are attributed to differences among serial positions in susceptibility to proactive inhibition.     

Mood-congruent free recall bias in anxiety

The present study evaluated the status of mood-congruent free recall bias in anxious individuals following incidental encoding of target words. In the first experiment, high trait anxiety individuals showed increased recall of threat-related information after an orienting task promoting lexical processing of target words. In a second experiment, both lexical and semantic orienting tasks were performed at study. In this experiment, anxious individuals displayed a mood-congruent recall bias only for target information processed at a lexical level. Theoretical and practical implications of these findings are discussed.     

The anatomy of free recall

The relative importance of various covert cues used in free recall is inferred on the basis of conditional probabilities of free recall given success vs failure of cued recall of the same material. Thirty-six names associated with pictures arranged in a 6 by 6 matrix were learned. A free recall test of names was followed by cued recall of names, with pictures, positions, or joint pictures and positions used as cues. Matching tests based on these cues were also administered. The tests were given at one of two stages of training, immediately or after 2 days. Pictorial and position cues are equally well encoded, but pictorial cues are less accessible and, therefore, relatively more useful in cued recall than in free recall. Position and pictorial information related to the names appears to be encoded and forgotten independently, and there is no evidence for summation of subthreshold encoding effect.     

Clustering by aphasics in free recall

Aphasic performance was compared to normal and left hemiplegic controls in the use of clustering to aid recall of a list of words in a multitrial free recall experiment. Use of clustering correlated with increased recall scores. Left hemiplegic performance was superior to aphasic and inferior to normal suggesting that the presence of brain damage decreased clustering but that this decrease was greater in the presence of aphasia. A second experiment examined the possibility of remediating aphasic clustering behavior by providing cues as a training device. Cues, which aided normals, did not benefit the majority of aphasics. Results are interpreted in terms of their relationship to cognitive functioning.