Perceptual grouping in good and poor readers

Williams, Mary C.; Bologna, Nancy B.

doi:10.3758/bf03207165

Cited by 49 publications

(18 citation statements)

References 20 publications

(16 reference statements)

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“…In addition, as far as focusing of attention is concerned, dyslexics showed a limited control of the focus size over time. Impaired focusing in children with learning and reading disabilities has also been reported by Sharma et al (1991) and Williams and Bologna (1985), respectively. Normal reading requires that each word is foveally viewed in order to achieve the highest spatial resolution analysis of the stimulus.…”

Section: Discussionmentioning

confidence: 81%

“…The deficit of automatic orienting shown by dyslexics may be explained in terms of three assumptions which are not mutually exclusive: (1) a deficit of the transient or magnocellular (M) pathway, as already discussed in Experiment 1, and/or (2) a reduced speed in the elementary operation of moving of attention, and/or (3) a difficulty to control the focus of attention correlated with a preference for a distributed attention modality, which would be peculiar to developmental dyslexia (Williams and Bologna, 1985;Geiger and Lettvin, 1987). Therefore, the purpose of this third experiment was to study some temporal aspects of attentional focusing in dyslexics and normally reading children.…”

Section: Methodsmentioning

confidence: 93%

“…It has been assumed that a dysfunction in the transient system might play a role in the occurrence of reading disorders (Stein and Walsh, 1997). Accordingly, several studies have reported the presence of attentional deficits associated with dyslexia (Williams and Bologna, 1985;Brannan and Williams, 1987;Geiger and Lettvin, 1987;Geiger et al, 1994;Rayner et al, 1989).…”

Section: Discussionmentioning

confidence: 99%

“…Also, a recent study by Sharma, Halperin, Newcorn et al (1991) reported a deficit of focused attention in a group of children with learning disabilities. Finally, results of a study of Williams and Bologna (1985) indicated a negative correlation between the effects of perceptual grouping and reading ability: grouping effects were stronger in poor readers. The authors suggested that poor readers relied heavily on the holistic information they acquired during reading before a more detailed analysis was accomplished by the focal attentional mechanism.…”

Section: Introductionmentioning

confidence: 93%

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Visual-Spatial Attention in Developmental Dyslexia

Facoetti

Paganoni

Turatto

et al. 2000

Cortex

241

182

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Orienting and focusing of visual attention are two processes strictly involved in reading. They were studied in a group of dyslexic children and normal readers. Shifting of attention by both peripheral and central visual cues was studied by means of the covert orienting paradigm. Focusing, consisting in the ability to control the size of the attentional focus, was investigated using simple reaction times in central vision. Results showed that dyslexics had a specific disability in the shifting of attention caused by a peripheral cue at short SOAs, and were also able to maintain attention focused for short periods of time only, presumably not long enough for efficient visual processing. Our results support the suggestion that visual selective attention deficits in disabled readers may be due to a specific difficulty in orienting and focusing.

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Section: Discussionmentioning

confidence: 81%

Section: Methodsmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 93%

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Visual-Spatial Attention in Developmental Dyslexia

Facoetti

Paganoni

Turatto

et al. 2000

Cortex

241

182

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“…In addition to the studies of speech perception, Mamen, Ferguson and Backman (1986) have reported that part-whole discrimination scores are related to age, but do not differ among children of different ages who are matched in reading ability. Finally, Williams and Bologna (1985) reported that perceptual grouping of non-linguistic stimuli is negatively correlated with reading ability. All of the above studies suggest that beginning readers attend to global aspects of information.…”

mentioning

confidence: 99%

Reading Ability and Attention to Words and Letters in Words

Marmurek

1988

Journal of Reading Behavior

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Students in grades 2, 4, and 6 were tested in two blocks of visual comparison trials. In one block, the primary task was to decide whether two words matched, and in the other block the task was to decide whether a single letter target matched the first letter of a word. On some trials in both blocks, the word comparison item was omitted and subjects were to decide whether a "7" occurred in the replacement display. On those probe trials, the "7" occurred either to the left or right of the display. In all grades, latencies for the primary task were faster for whole-word than for first-letter decisions. On the probe trials, latencies were faster when the probe item appeared in the first position of the display, but only in the block of firstletter trials. Moreover, the first-position advantage on probe trials was greater for good than for poor readers. The results were interpreted to be consistent with the hypothesis that both good and poor readers process words holistically. Poor readers are not more likely than good readers to attend to single

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Visual search performance in dyslexia

Iles¹,

Walsh²,

Richardson³

2000

Dyslexia

108

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According to the magnocellular theory of dyslexia, otherwise intelligent children may fail to learn to read because of abnormalities in the magnocellular layers of the lateral geniculate nucleus (mLGN). If this were the case, one would predict that dyslexic subjects who show a deficit on low-level psychophysical tasks which tax the magnocellular system would also have deficits on higher-level visual tasks which do not rely on the properties of mLGN cells but depend upon the functioning of areas whose main inputs originate in the mLGN. In other words, magnocellular deficits should be traceable at later stages of visual processing. One area where such later processing is thought to occur is the posterior parietal cortex, damage to which impairs function on some classes of visual search. To test this hypothesis, we tested two groups of dyslexic subjects and a group of non-dyslexic controls on a range of visual search tasks. One group of dyslexic subjects had elevated motion coherence thresholds, a sign of deficits at the early levels (e.g. mLGN) of visual processing, and the other group had normal motion coherence thresholds. If the magnocellular deficits extended to the parietal cortex, it follows that the subjects with elevated motion coherence thresholds should have deficit in visual search, whereas those with normal motion coherence thresholds should not. The dyslexics with a motion coherence deficit were also impaired on serial visual search tasks but not on a parallel search. The dyslexics with normal motion coherence performance were unimpaired on visual search. The deficit was expressed as an elevation in reaction times, but there was no difference between the groups either in error rates or in the way the tasks were ranked according to difficulty. The results suggest that those dyslexics who have visual problems related to magnocellular functions also have visual-attentional problems related to the functions of areas such as the parietal cortex, which are dominated by inputs originating in the magnocellular LGN.

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Perceptual grouping in good and poor readers

Cited by 49 publications

References 20 publications

Visual-Spatial Attention in Developmental Dyslexia

Visual-Spatial Attention in Developmental Dyslexia

Reading Ability and Attention to Words and Letters in Words

Visual search performance in dyslexia

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