Vowel generalization in normal and learning disabled readers.

Studied vowel–sound associations in 20 learning disabled (LD) children, 20 normal readers matched with the LD children for reading vocabulary (the VM group), and 20 normal readers matched with the LD sample on age (the AM group). All Ss were drawn from a population of LD and normal children in Grades 2–6 in a middle-class school district. The 3 groups were given the Vowel Generalization Test, which includes 25 regularly spelled words, 25 irregularly spelled words, and 25 nonsense words. Responses to each of the 3 item sets were scored according to vowel pronunciation (regular, irregular, and ungeneralized—vowel responses that are never signaled by the orthographic construction of a particular word), consonant pronunciation (correct or incorrect), and overall correctness. Results of ANOVA with post hoc comparisons showed that the LD and AM groups differed on all measures. However, comparisons of the LD and VM groups primarily revealed a tendency of the LD Ss to apply regular vowel associations less frequently and to apply ungeneralized vowel associations more frequently than the VM group. It is concluded that LD children are less likely than normal readers to apply major pattern associations in decoding unknown words and tend instead to produce vowel sounds that are never signaled by the particular orthographic construction. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of visual and auditory distractors on learning disabled and normal children's recognition memory performance.

Investigated whether distractibility in learning disabled (LD) children could be predicted on the basis of diagnosed visual and auditory learning deficits. 26 children in Grades 2–4 were classified as having visual or auditory reading disorders on the basis of the Illinois Test of Psycholinguistic Abilities. They and 17 normally achieving children from the same grades performed visual and auditory recognition memory tasks with visual or auditory distractors presented on 80% of the trials. Analysis of error frequencies revealed that with distractors, Ss in the 2 LD groups made more errors and did not improve over trials as much as control Ss. However, the predicted interaction between learning disability modality and task or distractor modality did not obtain. Rather, all 3 S groups made more errors when task and distractor were in the same modality. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Limitations of object-based feature encoding in visual short-term memory.

The present study investigated object-based feature encoding in visual short-term memory for 2 features within the same dimension that occur on different parts of an object. Using the change-detection paradigm, this experiment studied objects with 2 colors and objects with 2 orientations. Participants found it easier to monitor 1 rather than both features of such objects, even when decision noise was properly controlled for. However, no object-based benefit was observed for encoding the 2 features of each object that were of the same dimension. When similar stimuli were used but the 2 features of each object were from different dimensions (color and orientation), an object-based benefit was observed. These results thus impose a major constraint on object-based feature encoding theories by showing that only features from different dimensions can benefit from object-based encoding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of luminance on visual evoked potential amplitudes in normal and disabled readers

Adsorption of four 5-pyrazolone derivatives and two carboxylic acids from aqueous solutions was studied. Partition coefficients for the analyzed drugs were calculated. Good corelation between log(k1, k2) (Langmuir constants) and log (octanol-water partition coefficient) of the drugs were found. The higher log(k1k2) value the higher solubility of the non-narcotic and analgetic drugs.     

Organization of visual short-term memory.

The authors examined the organization of visual short-term memory (VSTM). Using a change-detection task, they reported that VSTM stores relational information between individual items. This relational processing is mediated by the organization of items into spatial configurations. The spatial configuration of visual objects is important for VSTM of spatial locations, colors, and shapes. When color VSTM is compared with location VSTM, spatial configuration plays an integral role because configuration is important for color VSTM, whereas color is not important for location VSTM. The authors also examined the role of attention and found that the formation of configuration is modulated by both top-down and bottom-up attentional factors. In summary, the authors proposed that VSTM stores the relational information of individual visual items on the basis of global spatial configuration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acquisition of word identification skills in normal and disabled readers.

10 normal and 10 disabled readers in Grades 5 and 6 were required to learn the meaning and pronunciation of unfamiliar words varying in word length and in letter–sound regularity and complexity. Results show that disabled readers were slower to name the unfamiliar words than normal readers, even after 3 sessions of practice. Naming accuracy and latency were found to be more strongly related to both regularity and complexity for disabled readers than for normal readers across 3 test sessions, suggesting that disabled readers were capable of using regular letter–sound correspondences to pronounce printed words but were hampered by weaker knowledge of these correspondences. Performance by both groups on a delayed naming task showed that the differences in naming speed were due to decoding rather than response-execution processes. The effects of word length on naming latency were more pronounced for disabled readers, suggesting that they relied on smaller subword components than normal readers when decoding the stimulus words. Disabled readers were slower at word naming than normal readers in all conditions, suggesting phonological coding and retrieval deficits. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verbal learning, retention, and memory.

It is argued that the traditional distinction between verbal learning and retention is arbitrary and that these processes cannot be differentiated. Although traditional operations have been used to distinguish between the 2 constructs, a whole host of more recent operations have served to break down the distinction which was traditionally used. As a result, even the arbitrary distinction between learning and retention which was once utilized is now no longer appropriate. It is suggested the term memory be substituted for learning and retention and that the use of this construct would provide several advantages. (french summary) (23 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Binding in short-term visual memory.

The integration of complex information in working memory, and its effect on capacity, shape the limits of conscious cognition. The literature conflicts on whether short-term visual memory represents information as integrated objects. A change-detection paradigm using objects defined by color with location or shape was used to investigate binding in short-term visual memory. Results showed that features from the same dimension compete for capacity, whereas features from different dimensions can be stored in parallel. Binding between these features can occur, but focused attention is required to create and maintain the binding over time, and this integrated format is vulnerable to interference. In the proposed model, working memory capacity is limited both by the independent capacity of simple feature stores and by demands on attention networks that integrate this distributed information into complex but unified thought objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Training and transfer-of-learning effects in disabled and normal readers: evidence of specific deficits

Two experiments were conducted to assess the specificity of training and transfer deficits in disabled readers, aged 7 to 9 years. Forty-eight children (reading disabled, age-matched normal controls, and reading-level-matched normal controls) participated in both a reading and a nonreading (music) acquisition paradigm. Children received instruction in grapheme-phoneme and symbol-note correspondence patterns, respectively. Posttraining tests (one day and one week) following rule training compared performance on trained exemplar items with performance on untrained transfer items. Results revealed that normal readers were able to transfer their rule knowledge in both the reading and nonreading (music) acquisition paradigms, while disabled readers were proficient only in the music task, and thus demonstrated transfer deficits specific to learning printed language. Transfer was optimally facilitated for all readers when training procedures included not only presentation of exemplars, but also cues for rule derivation and explicit statement of pattern invariances.     

Development of grammatical-sensitivity, phonological, and short-term memory skills in normally achieving and learning disabled children.

The development of a variety of grammatical-sensitivity and phonological skills was studied in 138 normally achieving, 65 reading-disabled, 63 arithmetic-disabled, and 15 attention deficit disordered (hyperactive) children 7 to 14 years old. Word recognition and phonics skills were highly related, and reading comprehension and phonics skills were less so. Grammatical sensitivity and short-term memory were significantly correlated with a variety of reading skills. Children with a reading disability showed a significant lag in the development of grammatical sensitivity and short-term memory and an even greater deficit in phonological skills. The children with a specific arithmetic disability had adequate grammatical abilities, but below-average memory skills at all ages. Children with an attention deficit but normal achievement scores did not have any major difficulties except on a reading-comprehension task that appears to have significant memory and attention components. The acquisition of reading skills is closely related to the development of grammatical and phonological skills, and deficiencies in these areas are related to difficulties with the acquisition of written language skills. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verbal coding and visual memory in aphasics

1 Dose-response curves for the positive inotropic and chronotropic responses to isoprenaline were obtained in atria from untreated guinea-pigs and those receiving various reserpine pretreatments. 2 Tension responses were unaffected, whereas rate responses were depressed by the lowest dose of reserpine (0.05 mg/kg i.p. at 24 hours). 3 With larger 24 h doses and a 3 day pretreatment, the rate and tension dose-response curves were progressively displaced to the left, indicating supersensitivity which was greater for tension at each pretreatment. 4 No supersensitivity to histamine or Ca2+ could be detected, leading to the conclusion that it was selective for the beta-adrenoceptor agonists possibly at the receptor level. 5 As an indication of the adrenergic neurone depleting effectiveness of each reserpine dosage, preparations were exposed to test doses of beta-phenylethylamine. 6 Salbutamol was a partial agonist in untreated atria, the maximum rate (63.3%) and tension (10.0%) responses being less than those for isoprenaline. In atria from reserpine pretreated animals the supersensitivity was revealed as an increase of this maximum compared with isoprenaline. 7 The significance of this observation in relation to the possible mechanism of the supersensitivity is discussed.     

Attention gating in short-term visual memory.

Investigated attention shift to a stream of numerals, in rapid serial visual presentation, using 3 graduate students with normal or corrected-to-normal vision. Ss detected a target embedded in a stream of letters presented at the left of fixation and, as quickly as possible, shifted their attention to a stream of numerals at the right of fixation. They attempted to report, in order, the 4 earliest occurring numerals after the target. Numerals appeared at rates of 4.6, 6.9, 9.2, and 13.4 sec. Analyses demonstrated that, for all Ss, targets, and numeral rates, the relative position of numerals in the response sequence showed clustering, disorder, and folding. Reported numerals tended to cluster around a stimulus position 400 msec after the target. Numerals were reported in an apparently haphazard order. The actual order of report resulted from a mixture of correctly ordered numerals with numerals ordered in the direction opposite to their order of presentation. Results are quantitatively described by a strength theory of order and are efficiently predicted by a computational attention gating model (AGM). The AGM may be derived from a more general attention model that assumes that (a) after detection of the target, an attention gate opens briefly to allow numerals to enter a visual short-term memory and (b) subsequent order of report depends on both item strength (how wide the gate was open during the numeral's entry) and on order information (item strength times cumulative strength of prior numerals). (78 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Short-term and working memory differences in language/learning disabled and normal adults

Fifteen adults who reported a childhood history of speech-language and/or learning disability (L/LD) were tested on two verbal memory tasks. Their performance on sentence repetition and reading span measures was compared with that of a matched control group who reported no childhood history of L/LD. Results indicated statistically significant group performance differences on both short-term and working memory tasks. This suggests that verbal memory difficulties may be a longterm component of L/LD.     

Verbal and nonverbal short-term memory impairment in untreated Parkinson's disease.

Extended previous research (J. A. Cooper et al, 1991) and examined whether the impairment in verbal and nonverbal short-term memory (STM) documented in chronically treated patients with Parkinson's disease (PD) is attributable to the pathology of the disease or to antiparkinsonian drug therapy. Verbal recall by a group of 58 never-treated PD patients was virtually perfect when the retention intervals were distractor free but was impaired, as compared with a matched group of 34 healthy control Ss, following distractor-filled intervals. Nonverbal recall by the PD group showed significant forgetting after distractor-free but not distractor-filled intervals. Recall was not related to depressive symptoms, motor disability, or distractor task performance. Thus, STM impairment in PD occurs for both verbal and nonverbal material and arises directly from the disease pathology rather than from antiparkinsonian medication. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parrel processing in visual short-term memory.

Visual short-term memory for the contrast and spatial frequency of sinusoidal gratings was measured in a delayed discrimination task in which the 2 stimuli to be compared were separated in time by 1-10 s interstimulus intervals (ISIs). Delayed discrimination thresholds for spatial frequency and contrast were compared, both when the 2 types of thresholds were measured in separate blocks of trials and when the 2 types of measures were randomly intermixed in an uncertainty paradigm, which required participants to process information about both dimensions on each trial. In both cases, accuracy of memory for spatial frequency was independent of ISI, but memory for contrast decreased as ISI increased. Performance was lower in the uncertainty case, but only by an amount predicted by statistical decision theory for independent sources. The results are consistent with a model assuming a set of parallel special-purpose visual discrimination and short-term memory mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Problem-solving strategies in learning disabled and normal boys: Developmental and instructional effects.

A developmentally sensitive problem-solving task, the 20-Questions Game, was utilized in this study to examine development- and treatment-related variables among 48 learning disabled and 48 normal boys of two age levels (8–10 years old and 11–23 years old). Subjects performed on three different versions of the experimental task before, immediately after, and two weeks after receiving one of two treatment packages, which differed in their emphasis on task-specific and metacognitive strategies. Results indicated that both younger boys and learning disabled boys demonstrated less efficient problem-solving skills than their older and normally achieving peers. In all subject groups, boys' ability to make use of specific problem-solving skills was highly influenced by variations in stimulus characteristics. Brief training was effective in improving the performance of all subject groups on trained and untrained materials at posttest and follow-up trials. However, expected differences in effectiveness between treatment packages were not realized. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The operative basis of performance on Piagetian memory tasks: Evidence from normal and learning disabled children.

Investigated the role of operative schemes in explaining older children's superior memory on past Piagetian memory tasks. In Exp I, 60 1st–4th grade concrete operational children—half with deficits in visual memory (learning disabled, LD)—reconstructed 2 stimuli in which operative schemes were or were not relevant (a seriated array vs an arbitrary color sequence). As predicted, LD children performed significantly worse than normals on the arbitrary stimulus only. Exp II tested whether this difference resulted simply from differential task difficulty. 28 preschoolers who either could or could not seriate reconstructed both stimuli. Only seriaters performed significantly better on the operative stimulus than on the arbitrary stimulus, supporting the Piagetian position. (2 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exploring developmental differences in visual short-term memory and working memory.

Although visuospatial short-term memory tasks have been found to engage more executive resources than do their phonological counterparts, it remains unclear whether this is due to intrinsic differences between the tasks or differences in participants’ experience with them. The authors found 11-year-olds’ performances on both visual short-term and working memory tasks to be more greatly impaired by an executive suppression task (random number generation) than were those of 8-year-olds. Similar findings with adults (e.g., Kane & Engle, 2000) suggest that the imposition of a suppression task may have overloaded the older children’s executive resources, which would otherwise be used for deploying strategies for performing the primary tasks. Conversely, the younger children, who probably never had the capacity or know-how to engage these facilitative strategies in the first place, performed more poorly in the single task condition but were less affected in the dual task condition. These findings suggest that differences in the children’s ability to deploy task-relevant strategy are likely to account for at least part of the executive resource requirements of visual memory tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Coarse-to-fine encoding of spatial frequency information into visual short-term memory for faces but impartial decay.

Face perception studies investigated how spatial frequencies (SF) are extracted from retinal display while forming a perceptual representation, or their selective use during task-imposed categorization. Here we focused on the order of encoding low-spatial frequencies (LSF) and high-spatial frequencies (HSF) from perceptual representations into visual short-term memory (VSTM). We also investigated whether different SF-ranges decay from VSTM at different rates during a study-test stimulus-onset asynchrony. An old/new VSTM paradigm was used in which two broadband faces formed the positive set and the probes preserved either low or high SF ranges. Exposure time of 500 ms was sufficient to encode both HSF and LSF in the perceptual representation (experiment 1). Nevertheless, when the positive-set was exposed for 500 ms, LSF-probes were better recognized in VSTM compared with HSF-probes; this effect vanished at 800-ms exposure time (experiment 2). Backward masking the positive set exposed for 800 ms re-established the LSF-probes advantage (experiment 3). The speed of decay up to 10 seconds was similar for LSF- and HSF-probes (experiment 4). These results indicate that LSF are extracted and consolidated into VSTM faster than HSF, supporting a coarse-to-fine order, while the decay from VSTM is not governed by SF. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Auditory short-term memory and digit span: Normal versus poor readers.

Investigated the relationship between reading comprehension level, digit span, and short-term memory for Morse codelike temporal patterns in 3 experiments. Consistent with previous research on children, Exp I using 60 undergraduates demonstrated that Ss performed better when the 1st pattern was auditory than when it was visual or tactual. In Exps II and III with 36 undergraduates and 98 5th graders, respectively, no relationship was found between digit span and accuracy in comparing patterns of tones presented a few seconds apart. However, both tasks discriminated between children with normal and poor reading comprehension scores on a standardized test (Reading Comprehension subtest of the California Achievement Tests). It appears that these 2 tasks index fundamental processes that underlie reading comprehension. Digit span seems to assess an individual's ability to rapidly develop meaningful codes in memory for incoming verbal stimuli. The auditory pattern comparison procedure appears to measure ability to maintain information in short-term memory. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)