The spacing effect in free recall emerges with development

Memory & Cognition - In two experiments, children were shown a series of pictures of common objects and were asked to free recall which pictured objects had been presented. Some pictures were...     

A model for free recall of two lists: Individual recall sequences and the effect of list-2-dominance

A free recall model which assumes a probability search for two kinds of items within one search set is outlined. Predictions for individual recall sequences are derived and an explanation for the effect of list-2-dominance is suggested. An index of dominance is also given.     

The effect of the length of to-be-remembered lists and intervening lists on free recall: a reexamination using overt rehearsal

In 3 experiments, the authors investigated the effects of to-be-remembered (TBR) and intervening list length on free recall to determine whether selective rehearsal could explain the previous finding that recall was affected only by TBR list length. In Experiments 1 (covert rehearsal) and 2 (overt rehearsal), participants saw 5- and 20-word lists and had to recall the list prior to that last presented list. In Experiment 3, either 1 or 2 lists were presented, and recall of TBR list was postcued. Recall proportion decreased with increased TBR list length. Moreover, the authors found extended recency effects when recall was replotted by when words were last rehearsed (Experiments 2 and 3) and an effect of intervening list length when rehearsal was reduced (Experiment 3).     

Memorization and recall of very long lists accounted for within the Long-Term Working Memory framework

In a recent paper, Hu, Ericsson, Yang, and Lu (2009) found that an ability to memorize very long lists of digits is not mediated by the same mechanisms as exceptional memory for rapidly presented lists, which has been the traditional focus of laboratory research. Chao Lu is the holder of the Guinness World Record for reciting the most decimal positions of pi, yet he lacks an exceptional memory span for digits. In the first part of this paper we analyzed the reliability and structure of his reported encodings for lists of 300 digits and his application of the story mnemonic. Next, his study and recall times for lists of digits were analyzed to test hypotheses about his detailed encoding processes, and cued-recall performance was used to assess the structure of his encodings. Three experiments were then designed to interfere with the uniqueness of Chao Lu's story encodings, and evidence was found for his remarkable ability to adapt his encoding processes to reduce the interference. Finally, we show how his skills for encoding and recalling long lists can be accounted for within the theoretical framework of Ericsson and Kintsch's (1995) Long-Term Working Memory.     

The spacing effect,free recall,and two-process theory: a closer look

Two experiments used procedures similar to those used by R. L. Greene (1989) to test the 2-process theory of the spacing effect and, in particular, the contextual-variability subtheory that applies to free-recall performance. Experiment 1 obtained a spacing effect in free recall following intentional learning but not following incidental learning, contrary to a previous result supporting the 2-process theory. Experiment 2 replicated the incidental-learning results when a slow presentation rate was used. However, with a faster presentation rate, a spacing effect was obtained, and performance exceeded that of the slow-presentation-rate condition at the longest lag. Neither the contextual-variability subtheory of 2-process theory nor an alternative deficient-processing hypothesis was able to account for all of the data.     

Limitations to the spacing effect: demonstration of an inverted u-shaped relationship between interrepetition spacing and free recall

The spacing effect refers to the finding that memory for repeated items improves when the interrepetition interval increases. To explain the spacing effect in free-recall tasks, a two-factor model has been put forward that combines mechanisms of contextual variability and study-phase retrieval (e.g., Raaijmakers, 2003; Verkoeijen, Rikers, & Schmidt, 2004). An important, yet untested, implication of this model is that free recall of repetitions should follow an inverted u-shaped relationship with interrepetition spacing. To demonstrate the suggested relationship an experiment was conducted. Participants studied a word list, consisting of items repeated at different interrepetition intervals, either under incidental or under intentional learn instructions. Subsequently, participants received a free-recall test. The results revealed an inverted u-shaped relationship between free recall and interrepetition spacing in both the incidental-learning condition and the intentional-learning condition. Moreover, for intentionally learned repetitions, the maximum free-recall performance was located at a longer interrepetition interval than for incidentally learned repetitions. These findings are interpreted in terms of the two-factor model of spacing effects in free-recall tasks.     

Executive processing in free recall of categorized lists

The present study examines the cognitive processes that operate in free recall of categorized lists by manipulating semantic structure of the lists and using a dual task methodology to restrict the processes that make demands on limited-capacity resources, the central executive resources. Relying on the assumption that, in free recall of categorized lists, the search for category names is a strategic controlled process that demands executive resources, lists with different numbers of categories ranging from 2 to 6 were employed. The results showed an effect of a secondary task on retrieval in the 4- and the 6-category list conditions, but not in the 2-category list condition. In contrast to retrieval, the secondary task interference at encoding produced an effect on recall of all three types of lists. An interesting finding was that an effect on clustering was found only when interference was present at encoding, not when it was at retrieval. This finding was in line with the suggestion (Troyer, Moscovitch, Winocur, Alexander, & Stuss, 1998) that switching (shifting between different category items) rather than clustering is related to executive functioning, and suggested that clustering may be a measure of two different types of processing: (1) executive processing at encoding and (2) automatic processing at retrieval. In addition, a different pattern of results was obtained when low frequency category words were used, indicating that the frequency of category words is an important determinant in free recall of categorized lists. Overall, the present results support the two-process account of retrieval of category words (Rosen & Engle, 1997) and the view that there are fundamental differences between encoding and retrieval processes (Naveh-Benjamin, Craik, Guez, & Dori, 1998; Naveh-Benjamin & Guez, 2000).     

Persistence of the spacing effect in free recall under varying incidental learning conditions

In three incidental learning experiments, an attempt was made to eliminate the processing deficit under massed presentation that is assumed to be responsible for the spacing effect in free recall, according to the attenuation of attention hypothesis. This was to be accomplished in Experiment I by requiring subjects to attend specifically to the total exposure duration of each item and in Experiments II and III by requiring subjects to rate the successive occurrences of repeated items on different semantic rating scales. The results of the three experiments consistently showed that these manipulations were ineffective in eliminating the spacing effect. Subsidiary analyses indicated that the activities involved in doing the semantic rating tasks do not provide direct access to retrieval cues useful for subsequent recall. Instead, it appears that, in order to perform the semantic rating tasks reliably, subjects must compare the to-be-rated item with previously rated items, and this comparison process may serve as the source of retrieval cues for subsequent recall.     

Coding processes in the free recall of associated word lists

An experiment is reported on the free recall of lists of 18 words. The lists consisted of words that were strongly or weakly associated to the eliciting stimulus, were members of either a single category or more than one category and were arranged into sets of three associated words or six associated words. Each list was presented once only and free recall required after a filled interval of 18 s. One half of the subjects were provided with cues at recall: the remainder were given no assistance. Recall efficiency increased with association level and with restricted category membership of the words in a set. Clustering at recall (when adjusted for opportunity) was greater in the 6×3 lists than in the 3×6 lists. The provision of cues only led to a significant facilitation in recall with lists consisting of 6 sets of 3 words. A detailed analysis of the recall data suggested the importance of the category membership variable in the production of the later recall.     

Spacing and lag effects in free recall of pure lists

Repeating list items leads to better recall when the repetitions are separated by several unique items than when they are presented successively; thespacing effect refers to improved recall for spaced versus successive repetition (lag > 0 vs. lag = 0); thelag effect refers to improved recall for long lags versus short lags. Previous demonstrations of the lag effect have utilized lists containing a mixture of items with varying degrees of spacing. Because differential rehearsal of items in mixed lists may exaggerate any effects of spacing, it is important to demonstrate these effects in pure lists. As in Toppino and Schneider (1999), we found an overall advantage for recall of spaced lists. We further report the first demonstration of a lag effect in pure lists, with significantly better recall for lists with widely spaced repetitions than for those with moderately spaced repetitions.     

The spacing effect in intentional and incidental free recall by children and adults: Limits on the automaticity hypothesis

Preschoolers, elementary school children, and college students exhibited a spacing effect in the free recall of pictures when learning was intentional. When learning was incidental and a shallow processing task requiring little semantic processing was used during list presentation, young adults still exhibited a spacing effect, but children consistently failed to do so. Children, however, did manifest a spacing effect in incidental learning when an elaborate semantic processing task was used. These results limit the hypothesis that the spacing effect in free recall occurs automatically and constrain theoretical accounts of why the spacing between repetitions affects recall performance.     

Rehearsal and retrieval processes in free recall of categorized lists

The relationships between rehearsal and subsequent retrieval characteristics were examined in the context of free recall of categorized lists. The results indicated a direct correspondence between the frequency of rehearsal and the order and speed of retrieval within categories. The same relationship obtained for the categories themselves. It was suggested that both retrieval time and order effects can be predicted in terms of the organization of input processing and the resultant repetition frequency of categories and exemplars.     

Working memory capacity and the spacing effect in cued recall

Spacing repetitions typically improves memory (the spacing effect). In three cued recall experiments, we explored the relationship between working memory capacity and the spacing effect. People with higher working memory capacity are more accurate on memory tasks that require retrieval relative to people with lower working memory capacity. The experiments used different retention intervals and lags between repetitions, but were otherwise similar. Working memory capacity and spacing of repetitions both improved memory in most of conditions, but they did not interact, suggesting additive effects. The results are consistent with the ACT-R model’s predictions, and with a study-phase recognition process underpinning the spacing effect in cued recall.     

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.     

The drawing effect: Evidence for reliable and robust memory benefits in free recall

In 7 free-recall experiments, the benefit of creating drawings of to-be-remembered information relative to writing was examined as a mnemonic strategy. In Experiments 1 and 2, participants were presented with a list of words and were asked to either draw or write out each. Drawn words were better recalled than written. Experiments 3–5 showed that the memory boost provided by drawing could not be explained by elaborative encoding (deep level of processing, LoP), visual imagery, or picture superiority, respectively. In Experiment 6, we explored potential limitations of the drawing effect, by reducing encoding time and increasing list length. Drawing, relative to writing, still benefited memory despite these constraints. In Experiment 7, the drawing effect was significant even when encoding trial types were compared in pure lists between participants, inconsistent with a distinctiveness account. Together these experiments indicate that drawing enhances memory relative to writing, across settings, instructions, and alternate encoding strategies, both within- and between-participants, and that a deep LoP, visual imagery, or picture superiority, alone or collectively, are not sufficient to explain the observed effect. We propose that drawing improves memory by encouraging a seamless integration of semantic, visual, and motor aspects of a memory trace.     

Strategies in the recall of clusterable lists

The present study assessed the effectiveness of a multi-session training aproach intended to teach mildly retarded adolescents to discover and utilize categorical list structure. The performance of a group of trained retarded individuals was compared with that of another group of retarded individuals who had simply received practice with the training materials. The performance of both retarded groups was evaluated relative to that of a group of equivalent-CA normal adolescents. Recall transfer with a new word list was indicated by the finding that trained retarded subjects achieved a criterion of perfect recall in fewer trials than untrained retarded subjects. Differences in the use of categorization strategies by normal and retarded subjects were interpreted in the light of the automatic-controlled processing distinction of Schneider and Shiffrin (1977).     

Examining the relationship between free recall and immediate serial recall: The serial nature of recall and the effect of test expectancy

In two experiments, we examined the relationship between free recall and immediate serial recall (ISR), using a within-subjects (Experiment 1) and a between-subjects (Experiment 2) design. In both experiments, participants read aloud lists of eight words and were precued or postcued to respond using free recall or ISR. The serial position curves were U-shaped for free recall and showed extended primacy effects with little or no recency for ISR, and there was little or no difference between recall for the precued and the postcued conditions. Critically, analyses of the output order showed that although the participants started their recall from different list positions in the two tasks, the degree to which subsequent recall was serial in a forward order was strikingly similar. We argue that recalling in a serial forward order is a general characteristic of memory and that performance on ISR and free recall is underpinned by common memory mechanisms.     

An adjacency effect in free recall

An adjacency effect was demonstrated at a high level of significance in the free recall, by 123 subjects, of a list of 40 high-frequency nouns presented in varying order on successive trials. The phenomenon referred to as the adjacency effect consists of the fact that when a subject is given repeated trials of study and free recall of a list of words (always presented in a different order), the probability of recalling a given item is greater when the item is presented temporally adjacent to an item which is already learned (as evidenced by recall on the previous trial) than when the item stands temporally between other items which are not yet learned. The enhancement of recall is greater when the item is presented between two previously learned items. The implications of the adjacency effect for verbal learning theory, particularly for the serial-position effect in serial learning and the concepts of interference and neural consolidation, are discussed.