A developmental study of vigilance in learning-disabled and nondisabled children

To test the proposition that learning-disabled children manifest a sustained attentional deficit, the Continuous Performance Test was administered to learningdisabled and nondisabled children at three age levels. Children were tested on three task lengths (5, 10, and 15 minutes) and two modalities (auditory and visual) in which dependent measures were correct detections and false responses, d′ and B values. As expected, learning-disabled children made fewer correct detections and more false responses and were less sensitive (d') to critical stimuli than were nondisabled children at all ages. There was also evidence to indicate that learningdisabled children apply different response criteria across age when compared to nondisabled children. B values varied significantly across age, group, modality, and time on task; d′ remained relatively unchanged across time periods. The popular notion that learning-disabled and younger subjects start a vigilance task with the same capacity as nondisabled older children but show a decline in attention as time on task increases was not supported.     

Allocation of study time and recall by learning disabled and nondisabled children of different ages

Study time and recall by learning-disabled and nondisabled children of five different ages were examined in a task requiring recall of digits that were presented at the child's own rate. Recall increased with age and was significantly higher by nondisabled than disabled children, particularly at older ages. As additional digits of each sequence were presented, study time by 8-year-old disabled and nondisabled groups were relatively constant, increased in older disabled and nondisabled children, but increased more in older nondisabled children than older learning disabled children. Instructions in hierarchical grouping of digits increased recall by all groups to a similar degree, but the increase by younger children and learning disabled children was associated with longer study times. The results suggest that allocation of study time and recall are developmentally delayed in learning disabled children.     

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.     

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.     

The dissociation of repetition priming and recognition memory in language/learning-disabled children.

Recent research has found that the performance of learning-disabled and non-disabled children is dissociated on explicit and implicit tests of memory (Lorsbach & Worman, 1989). The current study further examined this phenomenon by comparing language/learning-disabled (L/LD) and nondisabled children (NLD) on tasks measuring primed picture-naming and item recognition. Included within the design of the experiment was the manipulation of both presentation format (pictures or words) and retention interval (immediate or 1 day). Children were initially presented with pictures and words. Performance was measured both immediately and following a 1-day retention interval on a picture naming task, an item recognition task, and a supplementary measure of memory for presentation format. The magnitude of facilitation associated with primed picture-naming was found to be independent of item recognition performance. In addition, the effects of population (L/LD and NLD) and retention interval (immediate test or 1 day) each produced dissociations between the magnitude of naming facilitation and item recognition performance. Results were discussed in terms of their implications for our understanding of the nature of memory difficulties in L/LD children.     

Time sharing and dichotic listening asymmetry in normal and learning-disabled children

Time-sharing and dichotic listening techniques were used to examine cerebral lateralization for language function in 48 normal and 48 learning-disabled children. All subjects were matched according to age, sex, and handedness. An analysis of results indicated that both nornal and learning-disabled children demonstrated left hemisphere lateralization of language function on the time-sharing and dichotic listening tasks. However, no developmental trends were evident for either group. Differences observed in the performance of the normal and learning-disabled children may relate to how each group utilizes “verbal strategies” and processes simultaneous information in the left hemisphere. The results strongly question the notion that attributes learning disabilities to incomplete or delayed language lateralization and lend support to the notion that cerebral lateralization is not a developmental phenomena.     

Attentional deficit in learning-disabled children: evidence from visual half-field asymmetries

The structural theory of cerebral lateralization has been typically used to explain hemispheric asymmetries. However, the attentional model of brain functioning may help resolve some of the inconsistent findings with groups of learning-disabled children. To test this hypothesis, a visual half-field paradigm for word recognition was employed in a group of 26 learning-disabled and 26 normal children matched for sex, chronological age, and handedness. Three experimental conditions (unilateral, cued unilateral, and bilateral) and two word error types (visually and acoustically confusable words) were analyzed. The results indicated that normals produced the expected RVHF superiority under all experimental conditions, but the learning-disabled produced the expected RVHF superiority only under the cued unilateral condition. Learning-disabled children also made significantly more visually and acoustically confusable errors than normals and unlike normal children increased the number of acoustic errors in the RVF under bilateral stimulation. These results provide evidence that learning-disabled children may process information inefficiently and have brain activation patterns that are more susceptible to attentional effects.     

Language and visuospatial abilities in learning-disabled, brain-damaged, and nondisabled young adults

This study confirmed the construct validity of dysphasic errors but not of Block Design or dyscopia for 88 male and 22 female young adults, aged 17 to 29 yr. Right-hand sensorimotor deficits correlated with dysphasic errors but not with Block Design. Brain-damaged and learning-disabled with Halstead Impairment Index (HII) greater than or equal to 0.4 differed from nondisabled on both dysphasic errors and Block Design. Learning-disabled with HII less than 0.4 differed from nondisabled only for dysphasic errors. As a group, young learning-disabled adults had impaired language abilities. Learning-disabled with HII greater than or equal to 0.4 and brain-damaged had generalized neuropsychological deficits characterized by less adequate language and visuospatial abilities.     

Using story contexts to bias children’s true and false memories

The effects of embedding standard Deese/Roediger-McDermott (DRM) lists into stories whose context biased interpretation either toward or away from the overall themes of the DRM lists on both true and false recognition were investigated with 7- and 11-year-olds. These biased story contexts were compared with the same children’s susceptibility to false memory illusions using the standard DRM list presentation paradigm. The results showed the usual age effects for true and false memories in the standard DRM list paradigm, where 11-year-olds exhibited higher rates of both true and false recognition compared with the 7-year-olds. Importantly, when DRM lists were embedded in stories, these age effects disappeared for true recognition. For false recognition, although developmental differences were attenuated, older children were still more susceptible to false memory illusions than younger children. These findings are discussed in terms of current theories of children’s false memories as well as the role of themes and elaboration in children’s memory development.     

Visual and auditory selective attention and reflection-impulsivity in normal and learning-disabled boys at two age levels

Selective attention to visual and auditory stimuli and reflection-impulsivity were studied in normal and learning-disabled 8- and 12-year-old boys. Multivariate analyses, followed by univariate and paired-comparison tests, indicated that the normal children increased in selective attention efficiency with age to both visual and auditory stimuli. Learning-disabled children increased in selective attention efficiency with age to auditory, but not to visual, stimuli. Both groups increased with age in reflection as measured by Kagan's Matching Familiar Figures Test (MFF). The 8-year-old learning-disabled children were more impulsive than the 8-year-old normals on MFF error scores, but not on MFF latency scores. No difference occurred between the 12-year-old learning-disabled and normal children on either MFF error or MFF latency scores. Correlations between the selective attention scores and MFF error and latency scores were not significant.This research was supported in part by BEH grant G007507227. The authors are indebted to Eleanor McCandless for her assistance in securing the learning-disabled subjects and to James McLeskey and Michael Popkin for their assistance in collecting and analyzing data.     

Phonetically inaccurate spelling among learning-disabled, head-injured, and nondisabled young adults

We applied the Boder and Jarrico (1982, The Boder Test of Reading-Spelling Patterns, New York: Grune & Stratton) criteria to the WRAT spelling list and examined the phonetically inaccurate spelling error patterns of learning-disabled (LD), head-injured (HI), and nondisabled young adults. Phonetically inaccurate (PI) errors were reliably rated (interrater r = .94) and were correlated significantly more strongly with dysphasic errors (r = .33) than with dyscopia (r = .16). ANOVA showed that LD and HI, which did not differ, made significantly more PI errors than both nondisabled and HI. These results indicate that PI errors reflect an underlying language disorder. The results also suggest that PI errors are more frequent in brain-related disorders. Finally, when group differences in cognitive ability are statistically controlled, PI errors are more common only among LD persons.     

Hemispheric asymmetry and recategorized WISC-R patterns in learning-disabled and nondisabled children.

The relationship between hemispheric processing and recategorized WISC-R patterns (spatial strengths and depressed Acquired Knowledge scores) in 14 learning-disabled and 14 nondisabled boys was examined. A genetic-prenatal hormonal basis appears most plausible.     

Comprehension of nonverbal communication: A reexamination of the social competencies of learning-disabled children

This study was designed to determine whether learning-disabled (LD) children differed from nondisabled (NLD) children in their ability to comprehend nonverbal communication when potential attentional differences between the groups were controlled. In addition, the relationship between nonverbal comprehension and social competence was assessed. Thirty LD and 30 NLD boys between 9 and 12 years of age were administered a short form of the Profile of Nonverbal Sensitivity (PONS) to assess nonverbal comprehension; social competence measures included teachers' ratings of aggressive and withdrawn behaviors using the Behavior Problem Checklist, and blind judges' ratings of performance on a role-play of friendshipmaking skills. Under attention-incentive conditions, no performance differences between LD and NLD children were found on the PONS; however, LD children were judged to be more withdrawn and less socially skilled. While PONS scores were not related to other social competence measures, hey were associated with academic achievement and IQ. Results emphasize the importance of considering the presence of attentional problems in LD children that may interfere with an accurate assessment of their skills.     

Information processing and speech lateralization in learning-disabled children

The relationship between information processing and speech lateralization was investigated in learning-disabled children. The Kaufman Assessment Battery for Children (K-ABC) assessed simultaneous and successive processing while a dichotic listening paradigm with free recall and directed attention conditions assessed speech lateralization. A three-factor ANOVA design conducted on the dichotic data revealed that normal children demonstrated stronger right ear advantage (REA); whereas learning-disabled showed weaker right ear advantage. Further, lambda analyses conducted on individual subjects revealed that the learning-disabled did not demonstrate the REA, were not biased attenders, and did not get more right ear than left ear items when attention was directed to one ear. Multiple-regression analysis was used to predict sequential processing from the dichotic data for both groups. Learning-disabled children demonstrated a substantial deficit in sequential processing as compared to normal children. These results indicate that learning-disabled children may not have adequate cerebral lateralization of receptive speech processes, shift their attention more readily, and are more inadequate in sequential processing that presumably subserves language functioning. Perhaps learning-disabled children have deficiencies of processor capacity of salient areas of the left (language) hemisphere.     

Development of cerebral dominance: dichotic listening asymmetry in normal and learning-disabled children

The magnitude of the dichotic right-ear advantage was assessed in 48 normal and 48 learning-disabled children representing an age range of approximately 5 years. All subjects were matched according to age, sex, and handedness. An analysis of results indicated a significant right-ear advantage in both the normal and learning-disabled children, but revealed no developmental trends for either group. Differences observed in the performance of the learning-disabled and normal children may reflect variability in selective attention rather than differences in the degree of cerebral lateralization. These results suggest a need for a reconceptualization of the causative factors affecting children with learning disorders and lend support to the notion that cerebral lateralization is not a developmental phenomenon.     

Information processing in reading-disabled and nondisabled children

Reading disabled and nondisabled children (13-14 years of age) were presented lists of 10 words each at different rates (one word per 1, 2, and 4 sec), and immediately after the last word of each list they recalled the words in any order. Recall of the first few words presented from each list (the primacy effect) was lower in reading-disabled than nondisabled children, and slower presentation rates increased the primacy effect in both groups. These findings suggest that reading-disabled children are not completely failing to use elaborative encoding but are using less effective elaborative encoding than nondisabled readers. With all presentation rates, recall of the last few words (the recency effect) was comparable in both groups, suggesting that older reading-disabled children encode and recognize the stimuli and that elaborative encoding is deficient in reading-disabled in spite of adequate stimulus encoding and recognition.     

学习困难儿童元记忆能力的实验研究

该研究以有和无意义联系的两种中文词对为材料,采用2×3×2混合实验设计,对小学三到五年级的学习困难儿童与学优儿童的JOL监测判断水平和学习时间分配之间的差异及其发展特点进行研究。结果表明：（1）学习困难儿童的JOL判断等级显著低于学优儿童;（2）在自定步骤学习过程中,随着年级增长,学习困难儿童能够根据学习材料的性质决定其学习时间的分配策略,表现出一定的元记忆控制能力,但其分配策略的有效性不高;（3）学习困难儿童的JOL监测判断水平和学习时间分配策略从小三到小五在缓慢提高;（4）学习困难儿童的JOL监测判断和学习时间分配之间存在交互影响。     

Processing of occurrence-rate and item information by children of different ages and abilities

Two experiments compare the performance of children who vary in both age and learning ability. In the first experiment, learning disabled and nondisabled children from three age groups were tested for their incidental memory for frequency of occurrence information. In the second experiment, learning disabled and nondisabled children from two age groups were tested for their intentional memory of item information on a free recall test. In agreement with the notion that frequency is automatically encoded, all groups extracted frequency information and neither age nor learning ability influenced performance. However, both age and ability influenced performance on the recall test.     

Do learning-disabled children exhibit peripheral deficits in selective attention? An analysis of eye movements during reading

It has been suggested that deficits in selective attention play a functional role in the learning and behavior problems of children diagnosed as learning- disabled. In the present study, peripheral and central aspects of selective attention were distinguished and peripheral aspects were examined. The attending eye movements during reading of 12 fifth-grade learning-disabled children who read at the third-grade level were compared with 12 fifth-grade children who read at the fifth-grade level (grade placement controls) and 12 third-grade children who read at the third-grade level (reading level controls). The learning-disabled children did not differ from their reading level controls on any of W measures but showed a pattern of eye movements that was generally slower and less smooth than their grade placement controls. While these patterns might be considered to be immature relative to normal readers of the same age, they are not indicative of peripheral deficits in selective attention. Males, however, did exhibit more variability in duration of fixations and made more regressive eye movements than did females.