Input organization as a mediating factor in memory: A comparison of educable mentally retarded and nonretarded individuals

The effect of presentation context on the organization and recall of strongly related and weakly related words was examined in EMR adolescents and nonretarded fifth-grade children of the same mental age (131 months). In blocked presentation formats, subjects sorted words into experimenter-defined groups of four, in which the order of the groupings either changed from trial to trial (i.e., blocked-random), or was consistent across trials (i.e., blocked-consistent). In sort-prompt conditions, subjects were free to structure their own relationships among items during presentation, following instructions to form meaning-based groups (i.e., minimum-sort-prompt), or given explicit training in sorting categorization and sorting stability (i.e., maximum-sort-prompt). Both subject groups found the minimum-sort-prompt method to be as effective as the maximum-sort-prompt method for improving measures of recall and clustering relative to the blocked-random method. Nevertheless, nonretarded children showed higher levels of organization for strongly related items, and better recall and organization for weakly related items. Subsequent analyses suggested that the lower memory performance of the EMR individuals receiving weakly related items was the result of both inconsistent and poorly structured sorting schemes across trials.     

The effects of verbal labeling on short-term and incidental memory: A cross-cultural and developmental study

Effects of induced verbal labeling on short-term and incidental memory were studied in Yucatan, Mexico. The 208 subjects, evenly divided by sex, were selected from four age groups (7–8, 10–11, 13–15, 20–21 years) from a large public school. Stimuli were cards depicting both animals and objects familiar to all subjects, and were presented over 14 trials. Short-term memory was tested with a probed serial recall task on each trial; incidental memory was tested following the 14 trials. Several results conformed to findings with earlier studies using American subjects: short-term memory improved with age; primacy and recency recall were influenced by both age and labeling; and the typical inverted U-shaped incidental memory function was found. Verbal labeling apparently aided recall by focusing attention on the relevant items, but such overt labeling also impeded the strategy of verbal rehearsal used by older subjects. Cultural factors appeared to play a limited role in the present study; the common element of formal schooling, among both American and Yucatecan subjects, was hypothesized as a possible explanation of such cross-cultural similarities.     

Encoding specificity in the recall of pictures and words in children and adults

In this study, the modality of the retrieval cues (pictures or words) was varied in a cued recall task to determine how second and fourth grade children and college adults encode words (Experiment 1) and pictures (Experiment 2). According to the assumptions of the encoding specificity principle, cue modality should affect recall only to the degree to which subjects focus on modality specific (sensory) rather than nonmodality specific (semantic) information in stimuli. In both experiments, the results showed progressively smaller encoding specificity effects with increasing age. To ensure that differences in encoding activity were responsible for these effects, comparisons were made of recall patterns under intentional learn conditions, and under incidental conceptual and sensory orienting conditions. The recall patterns of the children in the conceptual orienting condition were similar to the adult patterns in the learn condition, and the adult recall patterns in the sensory orienting conditions were similar to those of the children in the learn conditions. These results suggest that there are developmental differences in encoding the sensory and semantic information in stimuli that may result from differences in the efficiency with which the semantic information in stimuli is processed. The results suggest that young children typically encode stimuli in a fashion that stresses the sensory aspects of the stimuli, and that recall suffers as a result.     

Developmental changes in children's use of semantic information in recall

Third and seventh graders (age 9 and 13 years) were randomly assigned to three instructional groups and engaged in a sort/recall task. The instructions emphasized either (a) recall of the items, (b) meaningful organization of the items, or (c) meaningful organization and recall of the items. Regardless of instruction, seventh graders sorted 20 unrelated items into semantically-based groupings and exhibited elevated levels of recall. Third graders instructed to group items to facilitate recall formed seemingly random groupings and recalled significantly fewer items than third graders instructed to make semantically-based groupings, even when some of these latter subjects were unaware of a subsequent recall trial. The results indicated that young children are capable of adult-like organizational strategies but are unaware of their relevance to recall performance or conditions under which organization might be an appropriate strategy.     

Children's recall of contextually integrable and nonintegrable episodic events

The hypothesis of this study is that children's deficiency in encoding input information may be attributed partially to a failure to fully integrate target and contextual information. Second and fourth grade children and college adults were shown sentences varying in internal integrability in a cued recall task for target nouns in the sentences. The sentences were internally semantically Congruous, Incongruous, or Anomalous. In acquisition, the subjects were told either to read the sentences (Read Encoding) or to rate the likelihood of the occurrence of the sentential event (Integration Encoding). The results showed large developmental differences in both levels of recall and the Congruity effect (superior recall for the Congruous relative to the Anomalous sentences) in the Read condition. These differences were minimized in the Integration condition. These patterns suggest young children are deficient in the contextual integration of episodic events, and, as a result, make inefficient use of semantic information in the encoding of input information.     

Free recall by deaf and hearing children: semantic clustering and recall in trained and untrained groups.

Free recall tasks with semantically categorizable stimuli were given to 60 deaf and 60 hearing children, divided equally among Grades 3, 5, and 7 (ages 9, 11, and 13 years, respectively). Half the children were trained to use semantic categorization as a memory aid after the first study-test trial. All subjects were told category labels and sizes on the third recall trial. As hypothesized, older children showed more spontaneous semantic clustering and higher recall scores than younger children. Training increased clustering in all groups, while the provision of category information at retrieval increased clustering regardless of training condition. Contrary to expectations, deaf children used semantic clustering as much as hearing children. Deaf children's recall scores, however, were significantly lower than hearing children's. The specific contrasts observed between deaf and hearing children's performance suggest that deaf children's recall deficiencies probably reflect either inadequate knowledge of category membership or inflexibility in reclassifying individual items, rather than a general inability to recognize and use the categorical nature of a list as a mnemonic aid.     

Sequential consistency and subjective clustering in the multitrial free recall of children

The organization imposed by children on lists presented in a multitrial free recall task was investigated in two experiments. In the first, 6 and 9 year olds were tested for multitrial free recall of an unstructured noun or mixed list, followed by two sorting trials. Organization was quantified using two structurally comparable indices. One was an index of subjective clustering, based on individual word groupings determined in the sorting trials, and the other was an index of the sequential consistency of recall order over successive trials. The older children had significantly higher scores on recall and subjective clustering but there was no age effect on sequential consistency. In the second experiment 6, 8 and 10 year olds were tested for multitrial free recall of line drawings of common objects. Two sorting trials followed and organization was quantified using the subjective clustering and sequential consistency indices. Recall and subjective clustering scores again showed significant increases with age. As before, no age effect on sequential consistency was found. The results were interpreted in terms of a differential sensitivity of the two indices to an age-related qualitative change in the basis of organization.     

Rehearsal strategy as a function of recall expectation

The subjects were divided into three groups with respect to their expectations concerning a recall task given after the final trial of the usual STM distractor procedure. Group 1 were told only that they would have to recall during each trial's recall interval, thus did not expect to have to recall again. Group 2 were told that they would have to recall all the words presented in the experiment at the end of the last trial, in addition to the trial-by-trial recall. Group 3 were told only that they would have to recall after all words had been presented and they sat passively through the presentation trials. In addition to their recall expectations, half of the subjects in each group received a 2-s presentation and half received a 5-s presentation interval. It was found that the length of the presentation interval had an effect on the number of words recalled at the end of all trials, but recall expectancy did not. However, expectancy did determine the rehearsal strategies of subjects and hence the serial positions from which items were recalled.     

Free recall of abstract and concrete words by American and Ghanaian college students

This investigation compared the free recall of concrete and abstract words in American and Ghanaian college students. There were no differences in the total number of words recalled as a function of concreteness or culture. However, recall of concrete words showed a greater improvement across trials for both cultures. Although there was no difference in the amounts of subjective organization exhibited by Ghanaian and American students, there was evidence for a greater serializing tendency among American students. It appears that the major cultural differences typically observed in African-American comparisons of free recall may be overshadowed by increases in the educational level of the subjects.     

A developmental comparison of the effectiveness of encoding tasks.

In Experiment 1, the free-recall performance of young children, college students, and older adults was examined. Subjects encoded words by simply learning them, by studying them in either base or elaborate sentence frames, or by constructing sentences. Overall recall was better for the college students than for the children or for the older adults, and the college students recalled best in the simple learning condition. The young children recalled best in the sentence construction condition; recall by older adults did not vary as a function of the encoding tasks. In Experiment 2, college students and older adults recalled a categorized list, encoding the words by simply learning them, by studying them in elaborate sentence frames, or by completing word fragments. For both age groups, simple learning produced the highest level of recall. These results suggest that organization provides the most effective encoding system and that older adults may need a more obvious basis for organization than do younger adults. Younger and older adults recalled equally well only when organization was discouraged by conceptual processing.     

The adaptive nature of children's overestimation in a strategic memory task

Kindergarten, first-, and third-grade children were given a multitrial sort-recall task with different items on each trial. Children were asked to predict how many items they would recall prior to each trial. We classified children into high- and low-overestimation groups based on their prediction accuracy on the first two trials and assessed changes in recall and strategy use over trials (trials 4/5 minus trials 1/2). Following predictions, at all grades, children in the high-overestimation group showed greater gains (or fewer losses) in recall than children in the low-overestimation group. Differences in strategy use over trials were generally nonsignificant. The results were interpreted as reflecting the adaptive nature of children's overestimation of their cognitive abilities.     

Categorical and schematic organization and the development of retrieval strategies

This study investigated the effects of schematic and categorical organization on young children's recall. Preschool and kindergarten children recalled either a taxonomic list or a story in one of two presentation conditions: an alternate condition, in which the material was presented, children recalled it and the procedure was repeated, or a successive condition in which the material was presented twice and children recalled it twice. Although preschool children's story recall was well organized, their list recall was poorly organized, and organization did not increase over recall trials in either presentation condition. In contrast, kindergarten children's recall of both the story and the list was well organized, and their recall was better organized on the second recall trial than on the first in both presentation conditions. These results are discussed in terms of the development of retrieval strategies during the preschool years/     

Development of hierarchical conceptual relationships in children's semantic memories

The present study was designed to determine when children first display evidence of hierarchical conceptual organization. Children aged 5 to 9 answered either semantic or sensory questions about a list of words composed of either superordinate terms, prototypical category instance, or moderately typical instances. In a later unanticipated cued recall task the children were given taxonomically related cues composed of the two remaining word types not used in the orienting phase. The 5-year-olds' performance revealed that they possessed a modest degree of hierarchically organized conceptual information, which by age 9 had developed to relatively sophisticated levels. In particular, it was found that the range of information contained in the 5-year-olds' conceptual hierarchies was considerably narrower than that of the 9-year-olds', which supports Rosch's contention that conceptual categories are first constructed around prototypical instances. The children's performance on the cued recall task was also compared to their performance on traditional class inclusion and object-sorting tasks. It was found that the object-sorting task overestimated, while the class inclusion task underestimated the extent to which conceptual information is hierarchically organized in 5-year-olds.     

Recall of familiar objects and projected color photographys of objects by mentally retarded individuals of comparable mental age.

The effects of cue-availability on short-term and long-term recall of 40 mentally retarded children were investigated. Subjects were chosen on the basis of comparable mental age (approximately 90 mo.) and randomly assigned to either an objects (high cues) group or slides (low cues) group. 52 familiar objects served as stimuli for the objects group and projected color photographs of the objects were presented to the slides group. In the short-term recall session the subjects were shown stimuli grouped into eight trials and asked to recall the names of the stimuli in each trial ten seconds after presentation. Delayed recall was obtained 48 hr. later in a free recall session. The objects group scored significantly higher than the slides group on memory span (p less than .01), short-term recall (p less than .001), and delayed recall (p less than .025). The facilitation of recall achieved by using three-dimensional stimuli was clearly demonstrated, and the relative degree of facilitation was comparable for both short- and long-term recall.     

Problem solving,recall, and isomorphic transfer among third-grade and sixth-grade children

Analogical reasoning processes were studied in third- and sixth-grade children. One group at each grade level received two analogs of the “farmer's dilemma”, a scheduling problem that requires seven moves for solution, during acquisition. Other groups received one analog or only a transfer task. On each trial the child heard a list of statements representing the exact series of moves necessary to solve the problem, was immediately asked to recall the list, materials representing the problem were then produced, and the child was asked to show how to solve it. A trial was terminated and a new one begun when an error was made on the physical task. Following criterial performance all children were transferred to an isomorphic analog and simply instructed to solve it. Third-graders in the two-analog condition required more trials in acquisition than the other groups, which did not differ from each other. Transfer was better following two analogs, but was unaffected by grade level. Grade level affected recall accuracy, but recall accuracy was not a good predictor of transfer performance. Trial-by-trial analyses suggested that propositions representing the solution are acquired piecemeal, but consolidation of the generalizable problem representation is abrupt.     

The effect of reinforcement and verbal rehearsal on selective attention in learning-disabled children

A central-incidental task of selective attention was administered to 100 learning-disabled boys — 48 younger children (81/2–101/2 years) and 52 older children (101/2–121/2 years). Subjects at both age levels were assigned to one of four conditions: (a) a standard condition; (b) a rehearsal condition, in which subjects were taught a verbal rehearsal strategy; (c) a reinforcement condition, in which correct responses were rewarded; and (d) a combined rehearsal-reinforcement condition. Older subjects recalled more central task but not more incidental task information than younger subjects. A measure of selective attention efficiency was also greater for older than for younger subjects. Central recall in the rehearsal-reinforcement condition was greater than in any other condition. Central recall was greater in the rehearsal condition than in the standard and reinforcement conditions. Selective attention efficiency was greater for both rehearsal conditions than for both nonrehearsal conditions. Incidental recall was higher for reinforcement subjects than for rehearsal subjects. Results suggest that induced verbal rehearsal improves central recall and selective attention in learning-disabled children. Reinforcement alone does not improve central recall but may when paired with rehearsal.This article is based on a Ph.D. dissertation completed by the senior author at the University of Virginia. Preparation of this article was supported in part by a contract (300-77-0495) from the Bureau of Education for the Handicapped, Office of Education, for the University of Virginia Learning Disabilities Research Institute.     

Semantic and acoustic processing in free and cued recall by educable mentally retarded adolescents

The abilities of educable mentally retarded adolescents to encode and retrieve words with semantic and acoustic cues were investigated in a free and cued recall task. On each of three trial blocks, seven groups of subjects were presented 20 unrelated stimulus words. Groups received either semantic, acoustic, or no encoding cues along with the stimuli. Free recall was requested from all subjects, followed immediately by a second period of either free recall or cued recall with the semantic or acoustic cues. Semantic cues were most effective when presented both at encoding and retrieval. The subjects were unable to use acoustic information as effective retrieval aids. Results were discussed in terms of encoding dimension dominance and mediational deficiencies.     

The influence of acoustic similarity on serial recall of letter sequences

Acoustic similarity is known to impair short-term memory (STM) for letter sequences. The present series of experiments investigated the effects of acoustic similarity on long-term retention. In the first experiment, subjects were asked to learn one of two lists of 8 letters, the letters being either of high or low acoustic similarity. Lists were visually presented for three trials, with subjects responding after each trial. Then subjects participated in an immediate memory task for digits which lasted for 20 min. Finally, subjects tried to recall the list of letters they had learned previously. Lists having items of high acoustic similarity were more difficult to recall on the first trial, but were better recalled on the delayed retention test. In a second experiment, groups of subjects were again asked to learn one of two lists of 8 letters differing in acoustic similarity, using different orders of the letters used previously. The procedures were identical except that in two groups, a STM task for digits intervened between the presentation and test of the letters. This intervening task minimized the effects of STM and eliminated the differences in retention found previously. In a third experiment, better long-term retention for material having high acoustic similarity was also obtained when subjects used a backward recall procedure. In the last experiment 14 item lists were learned to a criterion of two correct trials, and retention was tested after each trial and at a delay of 20 min. and 23 hr. No effect of acoustic similarity was found and little retention loss occurred. These results suggest that reducing the STM component by introducing a STM control or by lengthening the list caused the effect of acoustic similarity to disappear.     

Alternative theories of concept identification among older adults

The purpose of the present experiment was to investigate some predictions of hypothesis testing and S-R association (frequency) theories regarding memory for intratrial events on a conjunctive concept-identification task. They have received extensive study with young adults but not with older subjects. The individual events under investigation were feedback, responses, hypotheses, and stimuli. Hypothesis-testing theory requires subjects to retain information concerning the correct hypothesis from one trial to the next whereas frequency does not. 75 subjects (60-70 yr. old) participated in the study. Subjects had difficulty in recalling the correct hypothesis stated on previous trials. These errors occurred on problems with negative response trials, not with incorrect feedback. The results contradict predictions based on hypothesis-testing models but are consistent with frequency theory. Unlike in the studies based on younger adults, present subjects did not recall the hypothesis very well under the conditions in which hypothesis testing was made part of the primary task.