Rehearsal strategies can enlarge or diminish the spacing effect: Pure versus mixed lists and encoding strategy.

Using 5 experiments, the authors explored the dependency of spacing effects on rehearsal patterns. Encouraging rehearsal borrowing produced opposing effects on mixed lists (containing both spaced and massed repetitions) and pure lists (containing only one or the other), magnifying spacing effects on mixed lists but diminishing spacing effects on pure lists. Rehearsing with borrowing produced large spacing effects on mixed lists but not on pure lists for both free recall (Experiment 1) and recognition (Experiment 2). In contrast, rehearsing only the currently visible item produced spacing effects on both mixed lists and pure lists in free recall (Experiment 3) and recognition (Experiment 4). Experiment 5 demonstrated these effects using a fully within-subjects design. Rehearse-aloud protocols showed that rehearsal borrowing redistributed study from massed to spaced items on mixed lists, especially during massed presentations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The mix-up regarding mixed and unmixed lists in spacing-effect research.

J. W. Hall (see record 1992-30089-001) proposed that participants in spacing-effect experiments use massed repetitions as an opportunity to study previously presented items. He provided apparent evidence for this displaced-rehearsal strategy in a free-recall experiment involving unmixed lists consisting of all massed or all spaced repetitions. He argued that this strategy produces artifactual spacing effects when experiments involve mixed lists containing both massed and spaced repetitions. This raises the specter that much of the spaced-repetition literature might be contaminated by artifactual results because most experiments have used mixed-list designs. The authors replicated Hall's experiment and extended it by including critical control conditions. Although Hall's results are replicable, they are primarily attributable to factors that were uncontrolled in his study. There seems to be no compelling reason to question spacing effects obtained with mixed-list designs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detrimental Influence of Contextual Change on Spacing Effects in Free Recall.

Two experiments were conducted to determine the mechanism underlying the spacing effect in free-recall tasks. Participants were required to study a list containing once-presented words as well as massed and spaced repetitions. In both experiments, presentation background at repetition was manipulated. The results of Experiment 1 demonstrated that free recall was higher for massed items repeated in a different context than for massed items repeated in the same context, whereas free recall for spaced items was higher when repeated in the same context. Furthermore, a spacing effect was shown for words repeated in the same context, whereas an attenuated spacing effect was revealed for words repeated in a different context. These findings were replicated in Experiment 2 under a different presentation background manipulation. Both experiments seem to be most consistent with a model that combines the contextual variability and the study-phase retrieval mechanism to account for the spacing effect in free-recall tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of spaced repetitions on amnesia patients' recall and recognition performance.

This study examined the effects of repetition and spacing of repetitions on amnesia patients' recognition and recall of a list of words. Like controls, amnesia patients recognized items better when repetitions were spaced compared with when they were massed. This finding was attributed to the additional rehearsal that distributed presentations typically encourage. Amnesia patients also showed normal spacing effects in a recall task, suggesting that they were able to benefit from the variable encoding that spaced repetitions allow to establish additional retrieval cues. However, even though instructions to encode repeated items in a variable manner enhanced massed presentations to the point where spacing no longer produced an advantage for the normal controls, it did not have a similar effect for the amnesia patients. This led to the conclusion that amnesia patients cannot take advantage of strategically provided opportunities to enhance their variable encoding of interitem associations. Instead, it is suggested that the automatic activation of different aspects of items and interitem associations is responsible for the spacing effect in their recall. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spacing effects in memory: Evidence for a two-process account.

Memory for repeated items on a list improves as a function of the spacing between repetitions. It is shown that spacing effects are eliminated in relative frequency discrimination, absolute frequency estimation, and recognition when items are learned incidentally. Spacing effects in free recall are unaffected by intentionality of learning. The results suggest that spacing effects in tasks in which experimenter-supplied retrieval cues are available are due to a rehearsal strategy that allots fewer rehearsals to items repeated in massed fashion. Spacing effects in free recall are due to a separate process resulting from study-phase retrieval of repeated items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of talker variability on recall of spoken word lists.

Three experiments were conducted to investigate recall of lists of words containing items spoken by either a single talker or by different talkers. In each experiment, recall of early list items was better for lists spoken by a single talker than for lists of the same words spoken by different talkers. The use of a memory preload procedure demonstrated that recall of visually presented preload digits was superior when the words in a subsequent list were spoken by a single talker than by different talkers. In addition, a retroactive interference task demonstrated that the effects of talker variability on the recall of early list items were not due to use of talker-specific acoustic cues in working memory at the time of recall. Taken together, the results suggest that word lists produced by different talkers require more processing resources in working memory than do lists produced by a single talker. The findings are discussed in terms of the role that active rehearsal plays in the transfer of spoken items into long-term memory and the factors that may affect the efficiency of rehearsal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retrieving for rehearsal: An analysis of active rehearsal in children's memory.

Two experiments with 96 2nd graders and 24 6th graders explored the operation of retrieval processes in Ss' active rehearsal strategies. Both experiments used free-recall tasks, in which Ss were given instructions in active rehearsal as well as supports that might facilitate the retrieval operation and thus enhance both rehearsal and recall performance. In Exp I, 2nd and 6th graders were given visual or auditory access to an 18-item stimulus-word list. Results show that, by providing 2nd graders with an opportunity to view previously presented words, rehearsal activity and recall increased substantially, whereas the performance of the 6th graders was not affected. In Exp II, presentation time and visual access to a similar 18-word list were manipulated for 2nd graders. Results show that the provision of extra time for an item enabled Ss to execute a more active rehearsal strategy. Extra time had only minimal effects on recall, except when it was combined with visual access to the items. Findings suggest that retrieval per se is not necessary for the beneficial effects of active rehearsal, if other procedures can be followed to permit the juxtaposition of several items in rehearsal. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distributed rehearsals and the primacy effect in single-trial free recall.

In this study we repeated Rundus and Atkinson's (1970) overt rehearsal free-recall task to show that there exists a type of rehearsal, called distributed rehearsal, that is associated with strong recall effects. The probability of recall of items that received a single distributed rehearsal was increased by about .45 over items receiving zero distributed rehearsals. Items receiving two distributed rehearsals were recalled with a probability of .90 or greater. In contrast, total rehearsal time, although significant, was associated with smaller effects. Words that received at least one distributed rehearsal were typically rehearsed intermittently and carried to the end of the list; their effective retention interval was close to zero. The results indicate that the primacy effect is not associated with total rehearsal time, as has been previously assumed, but rather with the probability that a word receives one or more distributed rehearsals. This probability decreases rapidly with input position. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rate of forgetting in amnesia: II. Recall and recognition of word lists at different levels of organization.

Amnesic rate of decline of free recall, cued recall, and recognition of word lists with different levels of organization was investigated in 2 experiments. In Experiment 1, it was found that amnesic free recall of semantically related word lists declined at an accelerated rate, whereas free recall of lists of unrelated words declined at a normal rate. Cued recall and recognition performance of both kinds of word lists appeared to decline at a normal rate. In Experiment 2, the results of the free-recall and recognition conditions were replicated using an improved experimental design. The observed amnesic forgetting pattern is interpreted as arising from an impairment in consolidation of long-term memory for complex associations between 2 or more items and their study context that is caused by extended hippocampal system lesions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of paraphrased repetitions on the spacing effect.

In two experiments, we examined the "spacing" effect in students' memory for paragraphs and brief lectures. In the first experiment, students who read massed verbatim repetitions of paragraphs recalled less of the content than did students who read verbatim repetitions spaced across time. In addition, students who read paraphrased versions of the paragraphs in massed repetitions recalled as much as did students who read the paragraphs in the spaced conditions. For Experiment 2, we used a brief lecture as the to-be-learned material and replicated the results of Experiment 1. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recall latency following pure- and mixed-strength lists: A direct test of the relative strength model of free recall.

Strong items (e.g., those studied for a longer period of time) are not recalled faster than weak items in pure-strength lists. Although counterintuitive, this result is consistent with a relative strength model of free recall. In mixed-strength lists, by contrast, the relative strength model requires that strong items be recalled significantly faster than weak items. A considerable body of recent research on this issue suggests that, if anything, the opposite may be true. Four experiments reported here measured free-recall latency following pure- and mixed-strength lists. Recall latency for strong items was consistently shorter than that for weak items, but in mixed lists only. Moreover, as uniquely predicted by a relative strength model, in mixed lists, strong items were recalled more quickly than items from a pure-strength list of the same size, and weak items were recalled more slowly by a corresponding amount. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The "One-Shot" Hypothesis for Context Storage.

In 3 experiments motivated by the implicit memory literature, the authors investigated the effects of different strengthening operations on the list strength effect (LSE) for explicit free recall, an effect posited by R. M. Shiffrin, R. Ratcliff, and S. E. Clark (1990) to be due to context cuing. According to the one-shot hypothesis, a fixed amount of context is stored when an item is studied for at least 1 or 2 s. Beyond the initial context storage, increases in study time or different orienting tasks do not influence the amount of context that is stored, and thus only spaced repetitions should produce a positive LSE. Consistent with prior findings, spaced repetitions always produced a positive LSE, but increases in depth of processing, study time, and massed repetitions did not. A model implements the one-shot hypothesis, and a role for context storage as a link between episodic and semantic memory is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential roles of frequency and meaningfulness in free recall.

Performed 2 experiments with 91 experimentally naive high school students to study the comparative influence of frequency and meaningfulness (m) on free recall. In Exp. I, the free-recall scores of 3 lists of words matched for m but varying in frequency levels were compared. In Exp. II, free recall of 3 lists of words matched for their frequency but varying in their m values were compared. Findings reveal that it is the frequency and not m of the words that influences free-recall, and that the influence of frequency is noticeable in the early trials of free-recall learning. Findings are discussed in terms of the existing theories of verbal learning. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult age differences in memory for massed and distributed repeated actions.

Adult age differences in memory for actions were investigated in 2 experiments in which actions were repeated with massed or distributed spacing. In Exp 1, Ss received a mixed series of actions, half performed once, the others twice, with repetitions either massed or distributed. Young Ss recalled more actions than did the elderly, and more distributed actions were recalled than massed actions. However, the Age?×?Spacing interaction was not significant. A probable inhibitory mechanism with a mixed list was avoided in Exp 2 by use of unmixed series. Actions were performed once only, twice only in massed repetitions, or twice only in distributed repetitions. The age difference was significant, and more actions were recalled in the distributed condition than in either of the other conditions, the results of which did not differ from one another. The Age?×?Conditions interaction was negligible. These results imply that elderly Ss are as likely as young Ss to encode contextual information while performing actions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Immediate serial recall of mixed-modality lists.

Seven experiments are reported in which subjects were tested for immediate serial recall of mixed-modality lists. On mixed auditory-visual lists, there was an advantage for auditory items at all serial positions. This was due to both a facilitation of auditory items and an inhibition of visual items on mixed lists, as compared with single-modality lists. When presented on a list containing items read silently, recall of items that were silently mouthed by the subject demonstrated patterns similar to those found with auditory items. When presented on a list containing items read aloud, recall of mouthed items showed patterns similar to those found with silently read items. The auditory advantage on mixed lists was found even when the list items were acoustically similar or identical and was not reduced by midlist auditory suffixes. The results suggest that modality differences in recall of mixed-modality lists are based on information different from that responsible for modality differences in recall of single-modality lists. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The distinctiveness of the word-length effect.

The authors report 2 experiments that compare the serial recall of pure lists of long words, pure lists of short words, and lists of long or short words containing just a single isolated word of a different length. In both experiments for pure lists, there was a substantial recall advantage for short words; the isolated words were recalled better than other words in the same list, and there was a reverse word-length effect: Isolated long words were recalled better than isolated short words. These results contradict models that seek to explain the word-length effect in terms of list-based accounts of rehearsal speed or in terms of item-based effects (such as difficulty of assembling items). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extending the irrelevant speech effect beyond serial recall.

The irrelevant speech effect is the impairment of immediate memory by the presentation of to-be-ignored speech stimuli. The irrelevant speech effect has been limited to serial recall, but this series of 8 experiments demonstrates that it is considerably more general. Exps 1–3 show that (1) irrelevant speech inhibits free recall more than does white noise, (2) irrelevant speech impairs free recall even when the speech occurs after the to-be-recalled items, and (3) free recall is inhibited even when the speech is meaningless. Exp 4 failed to find an effect in free recall with 16-item lists. Exps 5A–5C extend the effect to recognition of 8-, 12-, and 16-item lists, with both phonologically related and phonologically unrelated lure items. Exp 6 extends the effect to a cued recall task that discourages the use of serial rehearsal of the to-be-remembered items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multiple roles for time in short-term memory: Evidence from serial recall of order and timing.

Three experiments are reported that examine the relationship between short-term memory for time and order information, and the more specific claim that order memory is driven by a timing signal. Participants were presented with digits spaced irregularly in time and postcued (Experiments 1 and 2) or precued (Experiment 3) to recall the order or timing of the digits. The primary results of interest were as follows: (a) Instructing participants to group lists had similar effects on serial and timing recall in inducing a pause in recall between suggested groups; (b) the timing of recall was predicted by the timing of the input lists in both serial recall and timing recall; and (c) when the recall task was precued, there was a tendency for temporally isolated items to be more accurately recalled than temporally crowded items. The results place constraints on models of serial recall that assume a timing signal generates positional representations and suggest an additional role for information about individual durations in short-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of spacing on memory for homogeneous lists.

The spacing effect refers to the advantage in memory for information repeated at separate points of time over information repeated in massed fashion. Three experiments showed that no spacing effect was found in free recall of lists containing items of high interstimulus semantic similarity. However, spacing effects were found when recognition or frequency-discrimination tests were given on these materials. The results support the hypothesis that several distinct processes underlie the spacing effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rehearsal training and developmental differences in memory.

To examine the relation between age-related changes in the activity of rehearsal and corresponding changes in recall, 96 2nd and 6th graders were trained in a variety of rehearsal techniques in an overt rehearsal free recall task. Consistent with previous work, developmental differences in the number of items rehearsed together were observed when Ss were given no particular training. These rehearsal differences were related to corresponding changes in the recall of initially presented items. The recall of 2nd-grade noninstructed Ss was similar to that of Ss instructed to rehearse only 1 or 2 items together; the serial position curves of these groups indicated no primacy effects. In contrast, the recall of Ss who rehearsed several items together was similar to that of noninstructed 6th graders, with significant primacy effects being observed in these conditions. Second-grade Ss were able to adopt this active rehearsal strategy and to continue using it on a transfer task. The facilitative effects of active rehearsal were mediated neither by priority in recall given to early list items nor by enhanced subjective organization. Results are discussed in terms of multistore models of memory. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)