The spacing effect: Additions to the theoretical and empirical puzzles

Four studies examined the MP-DP effect (spacing effect) in four quite different situations: recognition of letters, verbal discrimination, short free recall lists, and recall of MP items presented twice, with an intervening interval inserted to produce forgetting. MP-DP differences were found in all studies. Of particular interest were three interactions. Subjects with a low criterion of responding in the letter study lost the MP-DP effect over a 30-sec delay, and subjects with a high criterion did not. A clear MP-DP effect, but no lag effect, was found only with unmixed verbal discrimination lists. In free recall, a sharp lag effect was shown for words presented three times but not for words presented twice. A forgetting interval inserted between the two occurrences of an MP item did not appreciably aid its recall. The results were found to pose severe problems for current theoretical ideas about the spacing effect.     

The within-list distributed practice effect: Tests of the varied context and varied encoding hypotheses

The present studies provided separate tests of the varied context and varied encoding hypotheses of the MP-DP effect. The investigation of varied encoding used an incidental learning procedure in which the nature of the orienting task was manipulated such that the subject attended to different attributes of words (varied encoding) or only one attribute (same encoding). While the prediction that the recall of MP-DP items should be comparable under comparable levels of encoding was not supported, differences were obtained in recall of items under same and variable orienting task conditions. An MP-DP effect was obtained under the incidental learning procedure. Tests of varied context involved the presentation of target items in list contexts which were the same or different from list contexts on previous occurrences of the item. The prediction that recall of items surrounded by different context should exceed that of items surrounded by the same context was not supported.     

On the independence of judged frequencies for items presented in successive lists*

In an experiment examining retroactive interference effects in a frequency-judging task, all Ss were presented with a list of words occurring varying numbers of times according to either a massed- or distributed-practive (MP or DP) schedule. They were then asked to judge how often each word had occurred. Following this, Ss were given one of four types of second tasks a second list with different items followed by a frequency-judging task for that list (Condition New): a second list with items repeated from the first list but with different frequencies for each item, while either maintaining items as either MP or DP items (Condition Same) or switching MP items to DP, and vice versa (Condition Reverse): followed by a frequency-judging task for the second-list frequencies only: or a puzzle task for the amount of time required for second-list presentation and judgment in the other conditions (Condition None). Finally, all Ss were asked to recall List 1 frequencies, List 2 frequencies were less discriminable in Conditions Same and Reverse than in Condition New. Recall of List 1 frequencies, however, was not different for these three groups, but was poorer than in List 2 frequency judgments were not independent of List 1 frequencies.     

The spacing effect in the learning of word pairs

Following the presentation of a single list of word pairs consisting of a three-letter word on the left and a five-letter word on the right, groups of 64 Ss each were asked to recall the (a) three-letter words, (b) five-letter words, (c) intact pairs, or (d) five-letter words with the three-letter words provided. Two types of repeated pairs were presented, one in which the same three- and five-letter words were repeated together (same pairs) and one in which the same five-letter word was repeated with different three-letter words (different pairs). For half of the Ss in each recall group, the repetitions of a pair containing a given five-letter word were massed (MP); for the other half, the repetitions were distributed (DP). Recall of MP same pairs and the eomponents of these pairs was consistently poorer than that of DP same pairs. Recall of the repeated component of the different pairs was also poorer under MP than under DP. The results were interpreted as supportive of an attenuation-of-attention explanation of the spacing effect.     

Evidence for time-based models of free recall

Is memory temporally organized? According to temporal distinctiveness models of memory, temporally isolated items should be better remembered than temporally crowded items in free recall tasks. Here, we tested this class of model by varying the temporal isolation of items either predictably (Experiment 1) or unpredictably (Experiment 2) in a free recall task. In both experiments, item recall probability increased as a function of the temporal gaps both before and after the item. The results are taken as support for temporal distinctiveness models of memory, in which items are represented and recalled in terms of their positions along a temporal dimension.     

The self-choice effect from a multiple-cue perspective

The self-choice effect refers to the fact that self-chosen items are remembered better than experimenter-assigned items (Takahashi, 1991). The present study investigated the hypothesis that (a) response choice involves relational processing as activation of both target and context items, and (b) such activated context items are effective as potential retrieval cues for recall of target items. In the experiment, participants chose (choice condition) or were assigned (force condition) a target to remember for each trial. Prior to free recall of the target items, context words, related new words, or unrelated words were presented in a recognition task as potential retrieval cues. The results of a subsequent free recall test indicated that the incidental cues were more effective in the choice condition than in the force condition. Also, recognition resulted in a greater rate of successfully recognized context words at the cost of increasing falsely recognized related new words in the choice condition in comparison with the force condition. These results indicated that response choice activates context items at encoding, which operate as potential retrieval cues for recall of target items. Such cuing mechanisms operative in the self-choice effect are consistent with the multiple-cue theory proposed by Soraci et al. (1994; see also Soraci et al., 1999) for generative processing.     

Testing effects for common versus proper names

The present study examines the testing effect as a function of item meaningfulness. In Experiments 1 and 2 participants studied lists of words that could serve as proper names or occupations (e.g., Mr Baker or baker), with the items given in a name context for one group and an occupation context for a second group. During an intervening phase participants restudied some items and were given a cued recall test (Experiment 1) or a free recall test (Experiment 2) on other items. On a final free recall test memory was better for tested items than studied items in both the name and occupation contexts. Experiment 3 followed the same procedure as Experiment 1, except that participants studied lists of proper names that do not have alternative uses in the English language (e.g., Mr Anderson) or studied concrete nouns (e.g., letter). Tested items were better remembered on a final test than studied items, and there was no interaction with type of study material. These results show that the testing effect extends to proper names, material that is commonly assumed to differ from common names on several dimensions.     

List-strength effect: I. Data and discussion

Extra items added to a list cause memory for the other items to decrease (the list-length effect). In one of the present studies we show that strengthening (or weakening) some items on a list harms (helps) free recall of the remaining list items. This is termed the list-strength effect. However, in seven recognition studies the list-strength effect was either absent or negative. This held whether strengthening was accomplished by extra study time or extra repetitions. The seven studies used various means to control rehearsal strategies, thereby providing evidence against the possibility that the findings were due to redistribution of rehearsal or effort from stronger to weaker items within a list. Current models appear unable to predict these results. We suggest that different retrieval operations underlie recall and recognition, as in the SAM model of Gillund and Shiffrin (1984), which can be made to fit the results with certain relatively minor modifications.     

Effects of constrained choice on memory: The extension of the multiple-cue hypothesis to the self-choice effect

The self-choice effect is the phenomenon whereby self-chosen items are remembered better than experimenter-assigned items. This study examined whether the effect occurs when the choice is constrained by cuing, and whether the effect also occurs for unchosen items. In the experiment, 33 participants chose (choice condition) or were assigned (force condition) a target from three alternatives that were followed by a cue sentence as a criterion for the choice. Cue sentences corresponded to any of the three alternatives (free cuing) or to only one (constrained cuing). Participants then engaged in free recall of targets and subsequent recognition of all alternatives (chosen and unchosen items). Memory performance was enhanced by choice regardless of the constraints, but was also enhanced for unchosen items. These results indicate that "free choice" is not always critical for the self-choice effect, and that multiple cuing involving unchosen items is a plausible account for the retention advantage of choice procedures.     

The generation effect: a test between single- and multifactor theories

Single- and multifactor accounts of the generation effect (better memory for internally generated items than for externally presented items) were tested. Single-factor theories suggest that generation induces either stimulus-response relational processing or response-oriented processing. Multifactor theories suggest that generation induces both types of processing. In the first three experiments subjects either read or generated responses, and the degree of categorical structure within the list was manipulated. When categorical structure was minimal, large generation effects were observed for free recall and recognition, but not for cued recall. When categorical structure was high, however, a generation effect was observed for cued recall but not for recognition or free recall. A fourth experiment was performed to eliminate an uninteresting interpretation of the results. It is argued that a multifactor account is needed to explain these findings.     

Effects of context variation, intracategory variation, and spacing on the free recall of pictures

Abstract.— Two experiments examined the effects of encoding variability on the free recall of pictures. In Expt. I, drawn objects were presented 3 times in different pictorial contexts (RV) or in the same contexts (RR). In Expt. II, repeated stimuli were 3 different specimens of the same object category (VR) or the same object presented 3 times (RR). Spacing of repetitions was varied from zero to 15, and a mixed-list design was used. Both RV and VR items tended to be recalled better than and prior to RR items. Recall of RR and of VR items increased with increasing spacing, but recall of RV items showed no spacing effect. In a second recall test, preceded by 4 min of "thinking about" the pictures, the only remaining effect of spacing or of context variation was a low recall of massed RR items. VR items were still recalled better than and prior to RR items. It is suggested that spacing, and variation of the external context of pictures, facilitate retrieval when the time and effort spent on recall is limited, by increasing the numberlvariety of potential recall cues stored together with item information.     

Age differences in collaborative memory: the role of retrieval manipulations

In two experiments, we examined age differences in collaborative inhibition (reduced recall in pairs of people, relative to pooled individuals) across repeated retrieval attempts. Younger and older adults studied categorized word lists and were then given two consecutive recall tests and a recognition test. On the first recall test, the subjects were given free-report cued recall or forced-report cued recall instructions (Experiment 1) or free recall instructions (Experiment 2) and recalled the lists either alone or in collaboration with another subject of the same age group. Free-report cued recall and free recall instructions warned the subjects not to guess, whereas forcedreport cued recall instructions required them to guess. Collaborative inhibition was obtained for both younger and older adults on initial tests of free-report cued recall, forced-report cued recall, and free recall, showing that the effect generalizes across several tests for both younger and older adults. Collaborative inhibition did not persist on subsequent individual recall or recognition tests for list items. Older adults consistently falsely recalled and recognized items more than did younger adults, as had been found in previous studies. In addition, prior collaboration may exaggerate older adults’ tendency toward higher false alarms on a subsequent recognition test, but only after a free recall test. The results provide generality to the phenomenon of collaborative inhibition and can be explained by invoking concepts of strategy disruption and source monitoring.     

Temporal isolation effects in recognition and serial recall

Recent temporal distinctiveness models of memory predict that temporally isolated items will be recalled better than temporally crowded items. The effect has been found in some tasks (free recall, memory for serial order when report order is unconstrained, running memory span) but not in others (forward serial recall). Such results suggest that the attentional weighting given to a temporal dimension in memory may vary with task demands. Here, we find robust temporal isolation effects in recognition memory (Experiment 1) and a smaller isolation effect in forward serial recall when an open pool of items is used (Experiment 2). Analysis of 26 temporal isolation effects suggests that the phenomenon occurs in a range of tasks but is larger when it is useful to attend to a temporal dimension in memory. The overall pattern of results is taken to favor memory models that rely on multiple weighted dimensions in memory, one of which is temporal.     

Free‐listed items are effective cues for eliciting additional items in semantic domains

This study tested a cueing procedure for enhancing recall in semantic domains based on associative processes inferred from semantic clustering. Participants first free listed items exhaustively from a semantic domain (fruits or drugs). Then, to aid recall of additional items from the domain, participants received either the items they free listed as semantic cues (to trigger semantically similar items) or alphabetic cues (to trigger items beginning with a particular letter). Participants' strong semantic clustering and weak alphabetic clustering in free listing confirmed previous research on associative processes. By several measures, free‐listed items as semantic cues elicited moderately more additional items than alphabetic cues. Semantic cues elicited an appreciable proportion of items that would not have been identified at the aggregate level through free listing alone. These results indicate that using free‐listed items as semantic cues can be a useful adjunct for ethnographic applications of free listing. Copyright © 2002 John Wiley & Sons, Ltd.     

The development of conceptual and rote recall skills among school age children

One hundred eighty children from Grades K, 5, and 9 performed a recall task within one of four instructional conditions: serial recall; standard free recall; labeling free recall; labeling cued recall. The task required that Ss view and recall items from three successively presented sets of categorized pieture stimuli. Controls were imposed upon the associatice relatedness of items within sets so as to minimize the occurrence of associative responding during recall. The clustering data showed that kindergarten and fifth grade children are able to use conceptual skills to effectively mediate recall, but fail to effect these skills on a spontaneous basis in free recall. The results were discussed in line with the hypothesis that young children fail to engage in planful cognitive activity in recall tasks.     

Person memory and person judgments based on categorically organized information

Free recall, cued recall, and rating-like judgments — conceived as alternative modes of expressing memorized information — were assessed in a person memory task. The target person had been described with respect to the presence or absence of 48 different interests (e.g., Mozart, sonatas, tennis, boxing) in 12 interest categories (e.g., music, sports). The number of interests (vs non-interests) per category was manipulated as well as the order of the three sub-tasks. The pattern of results can be explained within a categorical coding framework which suggests two functionally independent stages of recall: (a) access to a higher-order memory code on the category level, and (b0 reconstruction of specific items within categories. In particular, judgments of the degree of interest in the abstract categories were only related to selective free recall on the categorical level but not specific level free recall. Cued recall of the degree of interest in specific items was only related to free recall on the specific level. Making the category judgments before the free recall task, rather than afterwards, increased the availability of categories but not specific items. And inconsistent patterns of interests impaired the cued recall of specific patterns within categories but did not affect the categorical level. A strong positivity effect (i.e., more interests recalled than non-interests) was also found, resembling the often noted advantage of positive information in other domains of cognitive psychology.     

Inhibitory control in memory: Evidence for negative priming in free recall

Cognitive control mechanisms-such as inhibition-decrease the likelihood that goal-directed activity is ceded to irrelevant events. Here, we use the action of auditory distraction to show how retrieval from episodic long-term memory is affected by competitor inhibition. Typically, a sequence of to-be-ignored spoken distracters drawn from the same semantic category as a list of visually presented to-be-recalled items impairs free recall performance. In line with competitor inhibition theory (Anderson, 2003), free recall was worse for items on a probe trial if they were a repeat of distracter items presented during the previous, prime, trial (Experiment 1). This effect was produced only when the distracters were dominant members of the same category as the to-be-recalled items on the prime. For prime trials in which distracters were low-dominant members of the to-be-remembered item category or were unrelated to that category-and hence not strong competitors for retrieval-positive priming was found (Experiments 2 and 3). These results are discussed in terms of inhibitory approaches to negative priming and memory retrieval. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

The importance of semantic similarity to the irrelevant speech effect

Irrelevant speech disrupts immediate recall of a short sequence of items. Salamé and Baddeley (1982) found a very small and nonsignificant increase in the irrelevant speech effect when the speech comprised items semantically identical to the to-be-remembered items, leading subsequent researchers to conclude that semantic similarity plays no role in the irrelevant speech effect. Experiment 1 showed that strong free associates of the to-be-remembered items disrupted serial recall to a greater extent than words that were dissimilar to the to-be-remembered items. Experiment 2 showed that this same pattern of disruption in a free recall task. Theoretical implications of these findings are discussed.     

The emergence of strategic knowledge activation in categorical clustering during retrieval

Elementary school children's free recall clustering has recently been explained as an automatic by-product of their developing knowledge base. In contrast, it is claimed that as children get older they become aware of the usefulness of category organization as a memory strategy that enables them to strategically activate category knowledge even during retrieval. To test this hypothesis an experimental procedure was developed where Ss first had to learn items in a noncategorical order to the criterion of two perfect serial recall trials. After a 12- to 15-min retention interval Ss unexpectedly received either serial or free recall (or--in Experiment 1--cued recall) instructions. In three experiments with second and fourth graders it was shown that (1) fourth graders' recall exceeded that of second graders only in the free, but not in the serial (or cued), recall condition, (2) higher levels of clustering were observed for fourth graders in the free recall condition, and (3) the grade effect on free recall data was eliminated when the influence of metamemory and categorical clustering statistically was partialled out (Experiments 1 and 3). This pattern of results proved robust against variants in which a metamemory question was asked or omitted prior to recall (Experiment 2) and manipulations in which age differences in categorical knowledge were minimized (Experiment 3). The results were interpreted as demonstrating fourth graders' strategic competence in activating category knowledge during retrieval and second graders' automatic knowledge activation.     

Temporal–contextual processing in working memory: Evidence from delayed cued recall and delayed free recall tests

Three experiments are reported that addressed the nature of processing in working memory by investigating patterns of delayed cued recall and free recall of items initially studied during complex and simple span tasks. In Experiment 1, items initially studied during a complex span task (i.e., operation span) were more likely to be recalled after a delay in response to temporal–contextual cues, relative to items from subspan and supraspan list lengths in a simple span task (i.e., word span). In Experiment 2, items initially studied during operation span were more likely to be recalled from neighboring serial positions during delayed free recall than were items studied during word span trials. Experiment 3 demonstrated that the number of attentional refreshing opportunities strongly predicts episodic memory performance, regardless of whether the information is presented in a spaced or massed format in a modified operation span task. The results indicate that the content–context bindings created during complex span trials reflect attentional refreshing opportunities that are used to maintain items in working memory.