Susceptibility to interference effects in short-term memory of normal and retarded readers.

The short-term memory for serial order of third and fourth grade normal and retarded readres (Ns = 13) was studied. Six pictures of common objects were spatially presented and subjects were required to reconstruct the sequence. On the first six trials, the same pictures were repeatedly presented in different sequences. On the seventh trial, a new set of stimuli was introduced. Analysis of short-term memory over trials showed that normal and retarded readers were similar on Trial 1 but the performance of retarded readers deteriorated more over trials than the performance of normal readers. Short-term memory of both groups improved on Trial 7. The results indicate a greater susceptibility to interference in the short-term memory of retarded readers.     

Word recognition under spatial transformation in retarded and normal readers

The recognition of words in normal, reversed, and inverted orientation was compared in a group of 9- to 11-year-old retarded readers and a matched group of normal readers. Using the ratio of reading times as an index of reading difficulty under spatial transformation, the results confirmed those of earlier studies which have shown that retarded readers' performance is less affected by spatial transformation than is normal readers'. However, an analysis in terms of the ratio of numbers of words read correctly pointed to just the opposite conclusion. The two sets of findings were reconciled by showing that they follow from the form of the function relating reading time to number correct, and by demonstrating that when word lists are equated for orthographic familiarity the performances of retarded and normal readers are equally affected by spatial transformation, whether the time or number ratio is used as an index.     

Development of phonetic memory in disabled and normal readers

The development of phonetic codes in memory of 141 pairs of normal and disabled readers from 7.8 to 16.8 years of age was tested with a task adapted from L. S. Mark, D. Shankweiler, I. Y. Liberman, and C. A. Fowler (Memory & Cognition, 1977, 5, 623–629) that measured false-positive errors in recognition memory for foil words which rhymed with words in the memory list versus foil words that did not rhyme. Our younger subjects replicated Mark et al., showing a larger difference between rhyming and nonrhyming false-positive errors for the normal readers. The older disabled readers' phonetic effect was comparable to that of the younger normal readers, suggesting a developmental lag in their use of phonetic coding in memory. Surprisingly, the normal readers' phonetic effect declined with age in the recognition task, but they maintained a significant advantage across age in the auditory WISC-R digit span recall test, and a test of phonological nonword decoding. The normals' decline with age in rhyming confusion may be due to an increase in the precision of their phonetic codes.     

Prediction of the reading and spelling performances of normal and retarded readers: A four-year follow-up

The purpose of this study was to determine the relative predictive accuracy of a number of measures employed in a 4-year longitudinal study of the neuropsychological abilities of normal and retarded readers. The results indicated that there were some very accurate predictive measures of reading and spelling achievement levels over the 4-year age span studied, and that the relative accuracy of these measures differed markedly for normal and retarded readers. Especially in the case of retarded readers, performance on the Underlining Test was a much more accurate predictor of eventual achievement levels in reading and spelling than were tests of reading, spelling, or psychometric intelligence.This investigation was supported in part under Grant #195 of the Ontario Mental Health Foundation, funds provided by the Research Division, Windsor Western Hospital Centre, and funds from the Ontario Department of Education Grants-in-Aid of Educational Research and Development program. Dr. M. W. Starr offered advice regarding the statistical design.     

An analysis of passive memory in normal and mentally retarded persons

The differential short-term retention of normal and mentally retarded persons is often attributed to differences in strategic functioning. There is, however, evidence for memory differences between these groups on tasks which minimize cognitive strategies. Many of the passive memory studies have been plagued with methodological and interpretative difficulties. The present experiment was an attempt to avoid these problems and clarify the possibility of passive memory differences.It was necessary to equate initial learning and control for rehearsal to compare the passive memory of normal and retarded persons across short, rehearsal-free intevals. The retention intervals were filled with a tonal detection task intended to prevent rehearsal.CA matched normal and retarded adolescents were required to recall sequences of consonants after periods of 0,9, and 27 sec. of tonal detection. These subjects also performed the detection task without the recall requirement over the same intervals. Subjects were classified as rehearsers and nonrehearsers, depending upon variations in their tonal detection accuracy, or response times across the two conditions. The main result was that normal and retarded nonrehearsers showed equal forgetting over the retention intervals.     

Assessing effects of viewing distance on normal Chinese reading: Some methodological and theoretical implications

Viewing distance determines a range of factors affecting reading performance. Previous studies of Chinese-character reading have shown considerable disagreement and inconsistency in their choice of viewing distances, however, with obvious implications for research in this area. The present study aimed to resolve this issue by determining the optimal viewing distance for studies of normal Chinese reading. Stimuli were pages of text that were composed of a standard Chinese typeface (Song) that was presented in a standard size (10.5 pt). Forty reading distances were used, ranging from 2.5 to 100.0 cm. Distances within the range of 7.5–55.0 cm produced faster reading rates than did the distances at either end of the continuum, and a regression model showed that 35 cm was the optimal viewing distance. These findings indicate an optimal range of retinal image sizes between 2.0° and 0.3° per character. The implications of these findings for understanding the processes that are involved in Chinese reading and for the appropriate presentation of Chinese stimuli in experiments are discussed.     

The effects of memory strategy instruction in the short-term motor memory of the mentally retarded

The present study investigated the effectiveness of teaching mnemonic strategies aimed at overcoming difficulties of mentally retarded students in retaining the motor short-term memory information of a preselected movement. The memory strategy employed was a combination of the "feel" of the movement and the spatial location of the hand relative to the body. The design of the study was a 2 x 2 (Instructional Treatment x Retention Condition) factorial. The instructional treatment factor included teaching the subjects a memory strategy versus no memory-strategy instruction. The retention condition factor included immediate recall and a 15-sec retention interval. There were five trials per subject. The data were interpreted as supporting the effectiveness of the memory-strategy instruction.     

Complexity effects in visuo-spatial working memory: implications for the role of long-term memory

Several studies have shown that the capacity of visuo-spatial working memory is limited by complexity. Using a variant of the Corsi blocks task, this paper investigates the effect of complexity of the to-be-remembered path on visuo-spatial memory span. Redundancy was determined by three Gestalt principles: symmetry, repetition, and continuation. Experiment 1 revealed an effect of path complexity. The subsequent experiments explored whether the superiority for recall of structured over complex paths can be attributed solely to the operation of visuo-spatial working memory, or whether it also reflects the use of long-term knowledge. Experiment 2 demonstrated that the effect of complexity remained, even when the mechanisms for visuo-spatial coding were removed by a secondary visuo-spatial task. In Experiments 3 and 4 subjects were trained in the recall of complex paths. This led to the creation of long-term memory representations for these paths, as shown by an improvement in their span, and a concomitant lack of transfer to new paths. Finally, Experiment 5 showed that one prior repetition of a complex path was sufficient to produce specific and long-term learning effects. These results point to the involvement of long-term memory processes in the temporary retention of visuo-spatial material for which representations exist in long-term memory. They also suggest that the effect of complexity may provide a tractable technique for investigating the mechanisms underlying the limits of visuo-spatial short-term storage.     

Nonselective read-out from iconic memory in normal, borderline and retarded adolescents

The hypothesis that retarded individuals read-out information from iconic memory at a slower rate, relative to their CA matched peers, was tested. Three IQ groups (normal, borderline and retarded) were selected with 10 subjects in each group. A tachistoscope presented a stimulus array and a post-stimulus cue for 100 msec. each, separated by a variable interstimulus interval (ISI). This stimulus array consisted of 10 letters arranged on two horizontal rows. The post-stimulus cue was a circle which surrounded the position of the correct letter. Nine ISIs were used and ranged from −100 (cue before array) to 500 msec. A 3 × 9 repeated-measures analysis of variance revealed non-significant effects for IQ and the IQ × ISI interaction. A significant effect was found for ISIs (p < .01) which reflected reduced performance at the intermediate ISIs for all intelligence groups. The hypothesis of a read-out deficit in the retarded was not supported. The present findings were discussed in relation to previous research which supported a read-out deficit in the retarded.     

Concreteness effects in different tasks: implications for models of short-term memory

This study investigates concreteness effects in tasks requiring short-term retention. Concreteness effects were assessed in serial recall, matching span, order reconstruction, and free recall. Each task was carried out both in a control condition and under articulatory suppression. Our results show no dissociation between tasks that do and do not require spoken output. This argues against the redintegration hypothesis according to which lexical-semantic effects in short-term memory arise only at the point of production. In contrast, concreteness effects were modulated by task demands that stressed retention of item versus order information. Concreteness effects were stronger in free recall than in serial recall. Suppression, which weakens phonological representations, enhanced the concreteness effect with item scoring. In a matching task, positive effects of concreteness occurred with open sets but not with closed sets of words. Finally, concreteness effects reversed when the task asked only for recall of word positions (as in the matching task), when phonological representations were weak (because of suppression), and when lexical semantic representations overactivated (because of closed sets). We interpret these results as consistent with a model where phonological representations are crucial for the retention of order, while lexical-semantic representations support maintenance of item identity in both input and output buffers.