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Abstract

Two experiments investigated visual processing asymmetries in normal and dyslexic readers, with unilateral tachistoscopic presentations. The experiments employed randomized or blocked presentations of verbal and nonverbal materials to determine whether previously reported differences between dyslexics and normals were due to structural hemispheric differences or to strategical processing differences. The results indicate that if dyslexics are unable to predict the nature of the stimulus, then they behave as normal readers. Their atypical laterality emerges only when they can adopt a strategy in anticipation of a specific type of stimulus. This leads to the suggestion that developmental dyslexia is associated more with inappropriate modes of thought than it is with hemispheric dysfunction.

References

Annett

(1970). A classification of hand preference by association analysis. British Journal of Psychology, 61, 303–321.

Bryden

M. P.

(1978). Strategy effects in the assessment of hemispheric asymmetry. In Underwood

(Ed.), Strategies of information processing (pp. 117–150). London: Academic Press.

Davidoff

(1982). Studies with non-verbal stimuli. In Beaumont

J. G.

(Ed.), Dividend visual field studies of cerebral organization (pp. 29–55). London: Academic Press.

Kerschner

J. R.

(1977). Cerebral dominance in disabled readers, good readers, and gifted children: Search for a valid model. Child Development, 48, 61–67.

Kimura

(1969). Spatial localization in left and right visual fields. Canadian Journal of Psychology, 23, 445–448.

Kinsbourne

(1973). The control of attention by interaction between the cerebral hemispheres. In Kornblum

(Ed.), Attention and performance IV. London: Academic Press.

Krueger

L. E.

(1970). Search time in a redundant visual display. Journal of Experimental Psychology, 83, 391–399.

Marcel

Katz

Smith

(1974). Laterality and reading proficiency. Neuropsychologia, 12, 131–139.

Marcel

Rajan

(1975). Lateral specialization for recognition of words and faces in good and poor readers. Neuropsychologia, 13, 489–497.

10.

Orton

S. T.

(1937). Reading, writing and speech problems in children. London: Chapman and Hall.

11.

Pirozzolo

F. J.

Rayner

(1979). Cerebral organization and reading disability. Neuropsychologia, 17, 485–491.

12.

Underwood

(1977). Attention, awareness, and hemispheric differences in word recognition. Neuropsychologia, 15, 61–67.

13.

Underwood

(1978). Concepts in information processing theory. In Underwood

(Ed.), Strategies of information processing (pp. 1–22). London: Academic Press.

14.

Underwood

Rusted

Thwaites

(1983). Parafoveal words are effective in both visual fields: Preattentive processing of semantic and phonological codes. Perception, 12, 213–221.

15.

Underwood

Whitfield

(1985). Right-hemispheric interactions in picture-word processing. Brain and Cognition, 4, 273–286.

16.

Witelson

S. F.

(1977). Developmental dyslexia: Two right hemispheres and none left. Science, 195, 309–311.

Hemispheric Asymmetries in Developmental Dyslexia: Cerebral Structure or Attentional Strategies?

Abstract

References