The effect of increased incentive on free recall by learning-disabled and nondisabled children

Immediate free recall by learning-disabled and nondisabled children was compared under two incentive conditions. Recall of the first few words of each list by disabled children and younger nondisabled children was lower than that by older nondisabled children, and receiving a monetary reward increased early list item recall by older disabled and nondisabled learners. These findings suggest that elaborative encoding processes, such as rehearsal, are impaired in younger disabled and nondisabled children and that receiving a reward increased elaborative encoding by older children. Similar recall of the last few list items by all groups suggests that attention and immediate memory are comparable in disabled and nondisabled children of different ages. Receiving a reward increased recall of the last few list items by younger disabled and nondisabled children, suggesting that a reward increased attention, immediate memory, or both, in these groups. Because receiving a reward increased recall equally in all groups, lower motivation did not appear to be responsible for the lower recall by younger nondisabled children and learning-disabled children.     

Enhancement of 4-year-old children's memory span for phonologically similar and dissimilar word lists

Previous research suggests that preschool children are deficient in rehearsal and that stimulus list repetitions can improve their recall, presumably by substituting for the products of rehearsal. However, the previous research included interitem or postlist retention intervals of several seconds or more. We examined the utility of list repetitions with reference to an ordinary span task in which spoken words were presented 1 s apart for immediate recall. Lists with phonologically similar versus dissimilar items were included, to determine if the overall pattern of recall could be made more similar to what is ordinarily obtained in older children. Cumulative repetition was found to cause a moderate increase in both memory span and the phonological similarity effect. Other types of list repetition provided more insight into types of stimulus redundancy that were helpful (e.g., repeated serial order information) or not helpful (e.g., forced articulatory coding) to children attempting to recall spoken lists. The underlying mnemonic processes are discussed.     

Amnesia,rehearsal, and temporal distinctiveness models of recall

Classical amnesia involves selective memory impairment for temporally distant items in free recall (impaired primacy) together with relative preservation of memory for recency items. This abnormal serial position curve is traditionally taken as evidence for a distinction between different memory processes, with amnesia being associated with selectively impaired long-term memory. However recent accounts of normal serial position curves have emphasized the importance of rehearsal processes in giving rise to primacy effects and have suggested that a single temporal distinctiveness mechanism can account for both primacy and recency effects when rehearsal is considered. Here we explore the pattern of strategic rehearsal in a patient with very severe amnesia. When the patient’s rehearsal pattern is taken into account, a temporal distinctiveness model can account for the serial position curve in both amnesic and control free recall. The results are taken as consistent with temporal distinctiveness models of free recall, and they motivate an emphasis on rehearsal patterns in understanding amnesic deficits in free recall.     

An adult model of preschool children’s speech memory

In previous work, it has been demonstrated that phonetic similarity among the items in a spoken list interferes with recall much more in school-aged children than in preschool children. The basis of this developmental change, however, is unclear. In the present study we examined the possibility that a developmental increase in the use of covert verbal rehearsal accounts for the change in the effects of phonetic similarity. Adults who recalled lists of spoken words during articulatory suppression tasks that blocked covert rehearsal were found to display patterns of recall that resembled those ordinarily found in 5-year-old children. The specific aspects of rehearsal responsible for these effects also were investigated.     

The temporal contiguity effect predicts episodic memory performance

One way to study the associative processes at work during episodic memory is to examine the order of participant responses, which reveal the strong tendency to transition between temporally contiguous or semantically proximal items on the study list. Here, we assessed the correlation between participants’ recall performance and their use of semantic and temporal associations to guide retrieval across nine delayed free recall studies. The size of the participants’ temporal contiguity effects predicted their recall performance. When interpreted in terms of two models of episodic memory, these results suggest that participants who more effectively form and retrieve associations between items that occur nearby in time perform better on episodic recall tasks. Sample code may be downloaded as a supplement for this article from http://mc.psychonomic-journals.org/content/ supplemental.     

The development of organized rehearsal

The purpose of this research was to evaluate the development or organization strategies in rehearsal processes. First-grade (age 7 years), third-grade (age 9 years), and fifth-grade (age 11 years) children were exposed to a memory task which involved multiple overt rehearsal and recall phases. The children were either free to rehearse any words from a taxonomically structured list or they were taught to rehearse in categories. The recall phase was either free or categorically cued. The number of repetitions in rehearsal increased only as a function of age. All of the independent variables facilitated the amount of organized rehearsal and the amount of retention. Children at all ages were able to maximize the relative amount of organized rehearsal when rehearsal was cued. The correlational analysis of the dependent variables indicated that for young children the quantity of rehearsal was linked to retention, but for older children the quality of rehearsal was related to retention. The results were interpreted as demonstrating the bases for production inefficiencies.     

The use of the cumulative rehearsal strategy: A developmental study

This study was designed to address two issues: (1) At what age do children spontaneously use a cumulative rehearsal strategy; and (2) What effect does the use of the strategy have on their performance?Twenty-eight children at each of five grade levels (nursery, kindergarten, 1, 3, and 5) were tested in a serial-position recall task. Stimuli were pictures of common objects and animals whose labels were one or two syllables in length. Following testing, the children were asked to report the memory strategy they had used.The assumption was made that children who were using a cumulative rehearsal strategy would perform better on series of one-syllable items than on series of two-syllable items. As predicted, nursery, kindergarten, and first-grade subjects correctly recalled as many two-syllable as one-syllable items: Both third- and fifth-graders recalled significantly more one-syllable than two-syllable items. Results indicated that (1) young children do not spontaneously use a cumulative rehearsal strategy until after first grade, and (2) the use of rehearsal did not facilitate overall performance of the rehearsers relative to the nonrehearsers at any grade level. Results are discussed in terms of their theoretical implications for the study of memory development.     

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.     

Developmental differences in rehearsal and free recall

The purpose of this experiment was to analyze developmental differences in rehearsal strategies which may mediate the commonly found age effect on free recall. As expected, significant age differences in recall were found; analysis of rehearsal strategies showed that fifth and eighth graders tended to repeat stimulus words immediately after presentation, and not enter items into subsequent rehearsal sets. Adults, in contrast, tended to reenter items for additional rehearsal, and had larger rehearsal buffers. Immediate repetition may have served as additional massed presentation trials, which are less consequential for learning than later reentry of items (spaced trials). It was inferred that children engaged primarily in maintenance rehearsal, and adults in both maintenance and elaborative rehearsal.     

Rehearsal in immediate serial recall

We report for the first time overt rehearsal data in immediate serial recall (ISR) undertaken at three presentation rates (1, 2.5, and 5 sec/word). Two groups of participants saw lists of six words for ISR and were required either to engage in overt rehearsal or to remain silent after reading aloud the word list during its presentation. Typical ISR serial position effects were obtained for both groups, and recall increased with slower rates. When participants rehearsed, they tended to do so in a cumulative forward order up to Serial Position 4, after which the amount of rehearsal decreased substantially. There were similarities between rehearsal and recall data: Both broke down toward the end of longer sequences, and there were strong positive correlations between the maximum sequence of participants' rehearsals and their ISR performance. We interpret these data as suggesting that similar mechanisms underpin both rehearsal and recall in ISR.     

Retrieval processes for serial order information

Three experiments sought to specify how list structure and rehearsal pattern influence the retrieval of well-learned serial order information. Subjects learned a serial list of 12 words followed by a probed recall task measuring response time. Adjacent list items served as retrieval cues to permit probing of an item by cues which maintained or crossed semantic or rehearsal boundaries. Evidence for structure in serial recall was inferred from the large cue format effects on response time. Such effects were found to be consistent with the semantic relationships in categorized lists and the acquisition rehearsal pattern in unrelated lists. When rehearsal grouping and semantic relatedness were in conflict. the cue format effects conformed mainly to the rehearsal pattern. Extended practice over five sessions did not eliminate these effects for many of the serial items. These results suggest that the structure of the serial list. whether based on previous associations or present rehearsal patterns. can provide a basis for retrieval. A hierarchical search model based on item and order information provided good fits of the data. The model suggested that response time varies with cue formats because cues differ in their efficiency at directing search to the correct response in the list structure. The structure. which is acquired at the time of learning. determines cue efficiency and. hence. the subsequent effects upon response time.     

Memory, acquisition, and category clustering in learning-disabled children.

In Experiment 1, single trial, immediate-free recall of learning disabled and nondisabled children was compared. The primacy effect in learning-disabled children was lower, suggesting that rehearsal or other types of elaborative encoding may be deficient in these children. In Experiment 2, acquisition of randomly presented categorical lists in a multitrial-free recall task was compared in learning disabled and nondisabled children. One-half of each group was required to learn the same number of words (34 per list), whereas list length for the other half exceeded the primacy effect of each child in immediate-free recall to the same degree. When the same number of items was learned, acquisition was slower in learning disabled than nondisabled children. When the number of items varied according to the primacy effect of each child, acquisition of both groups was similar. Clustering was lower in learning disabled than nondisabled children. In Experiment 3, multitrial-free recall acquisition of categorical lists was examined in a subject-paced task. When the number of words learned exceeded the primacy effect of each child to the same degree, trials to criterion were similar in both groups but, when the children learned the same number of items, learning-disabled children required more trials to criterion. Presentation rates were faster in learning-disabled children. Presentation rates were negatively correlated with trials to criterion and positively correlated with clustering and primacy in immediate-free recall, suggesting that study time may be taken up by clustering, rehearsal, and/or other encoding strategies. Deficient elaborative encoding may be responsible for the slower acquisition of learning-disabled children.     

Age-related deficits in free recall: The role of rehearsal

Age-related deficits have been consistently observed in free recall. Recent accounts of episodic memory suggest that these deficits could result from differential patterns of rehearsal. In the present study, 20 young and 20 older adults (mean ages 21 and 72 years, respectively) were presented with lists of 20 words for immediate free recall using the overt rehearsal methodology. The young outperformed the older adults at all serial positions. There were significant age-related differences in the patterns of overt rehearsals: Young adults rehearsed a greater number of different words than did older adults, they rehearsed words to more recent serial positions, and their rehearsals were more widely distributed throughout the list. Consistent with a recency-based account of episodic memory, age deficits in free recall are largely attributable to age differences in the recency, frequency, and distribution of rehearsals.     

Temporal isolation does not facilitate forward serial recall—or does it?

In numerous recent studies in short-term memory, it has been established that forward serial recall is unaffected by the temporal isolation of to-be-remembered items. These findings contradict the temporal distinctiveness view of memory, which expects items that are temporally isolated from their neighbors to be more distinct and hence remembered better. To date, isolation effects have only been found with tests that do not constrain output order, such as free recall. This article reports two experiments that, for the first time, report a temporal isolation effect with forward serial recall, using a running memory task in which the end of the list is unpredictable. The results suggest that people are able to encode and use temporal information in situations in which positional information is of little value. We conclude that the overall pattern of findings concerning temporal isolation supports models of short-term memory that postulate multidimensional representations of items.     

A deeper analysis of the spacing effect after “deep” encoding

The most common encoding strategies used by participants in word list studies include rehearsal and using the story mnemonic. Previous studies have suggested that with a rote-rehearsal strategy, mixed lists lead people to borrow rehearsal time from massed items and to give it to spaced items. Using rehearse-aloud methodologies, we demonstrated in Experiment 1 that the borrowing effect does not occur in the story mnemonic. However, the rates of rehearsal of individual items provided a good prediction of their subsequent recall rates, with spaced items being rehearsed more often in both mixed and pure lists. In Experiment 2, we demonstrated that creating "story links" between items enhanced recall, but it did not affect the magnitude of the spacing effect. These results suggest that a massed-item deficit in encoding may underlie the spacing effect in the story mnemonic.     

From brief gaps to very long pauses: temporal isolation does not benefit serial recall

Theoretical explanations of short-term memory for serial order can be classified on the basis of whether or not they invoke time as a causal variable. According to time-based accounts, such as temporal distinctiveness theories, there is an intimate link between time and memory. Event-based theories, by contrast, postulate processes such as interference or rehearsal to account for seemingly temporal phenomena in short-term memory. We report an experiment that examined whether extended temporal isolation benefits serial recall performance. Regardless of whether the participants were quiet or performed articulatory suppression during list presentation, temporal isolation did not benefit memory even if items were separated from their neighbors by up to 7 sec. These findings challenge time-based theories of short-term memory.     

Predictability as a task demand in single-trial free recall

In a series of five single-trial free recall experiments it was demonstrated how manipulations of predictability in a list learning task caused reliable effects on the recency portions of the nominal serial position curve. Predictability was defined as knowledge of when the next item in the list should appear ( interval predictability) and knowledge of when the list should end and thus when recall could start ( signal predictability). Predictability was manipulated by varying the inter-item intervals within a list according to different "encoding functions", e.g. a successive increase (Condition I ) or decrease (Condition D ) of the inter-item intervals. Predictability was also manipulated by means of post-list recall signals. The data obtained show, that depending on how the interval and the signal predictabilities were manipulated, either Condition I or Condition D lists could be made more beneficial to the recall of recency items than lists with constant inter-item intervals (Condition C ). Previous encoding, storage and retrieval models were found not to give satisfactory accounts of the obtained recency effects. Neither could any traditional rehearsal model explain the data. Instead it is proposed that the predictability of stimuli in a list learning task explains how changes in recall of recency items come about. It was also hypothesized that the temporal demands, afforded to the subjects by the different encoding functions, explained the obtained output order variations.     

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.     

Do children use different forms of verbal rehearsal in serial picture recall tasks? A multi-method study

ABSTRACT

Use of verbal rehearsal is a key issue in memory development. However, we still lack detailed and triangulated information about the early development and the circumstances in which different forms of rehearsal are used. To further understand significant factors that affect children’s use of various forms of rehearsal, the present study involving 108 primary school children adopted a multi-method approach. It combined a carefully chosen word length effect method with a self-paced presentation time method to obtain behavioural indicators of verbal rehearsal. In addition, subsequent trial-by-trial self-reports were gathered. Word length effects in recall suggested that phonological recoding (converting images to names – a necessary precursor for rehearsal) took place, with evidence of more rehearsal among children with higher performance levels. According to self-paced presentation times, cumulative rehearsal was the dominant form of rehearsal only for children with higher spans on difficult trials. The combined results of self-paced times and word length effects in recall suggest that “naming” as simple form of rehearsal was dominant for most children. Self-reports were in line with these conclusions. Additionally, children used a mixture of strategies with considerable intra-individual variability, yet strategy use was nevertheless linked to age as well as performance levels.