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No deficiency in left-to-right processing of words in dyslexia but evidence for enhanced visual crowding

Maaike Callens (UGent) , Carol Whitney, Wim Tops (UGent) and Marc Brysbaert (UGent)
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Organization
Abstract
Whitney and Cornelissen hypothesized that dyslexia may be the result of problems with the left-to-right processing of words, particularly in the part of the word between the word beginning and the reader's fixation position. To test this hypothesis, we tachistoscopically presented consonant trigrams in the left and the right visual field (LVF, RVF) to 20 undergraduate students with dyslexia and 20 matched controls. The trigrams were presented at different locations (from –2.5° to + 2.5°) in both visual half fields. Participants were asked to identify the letters, and accuracy rates were compared. In line with the predictions of the SERIOL (sequential encoding regulated by inputs to oscillations within letter units) model of visual word recognition, a typical U-shaped pattern was found at all retinal locations. Accuracy also decreased the further away the stimulus was from the fixation location, with a steeper decrease in the LVF than in the RVF. Contrary to the hypothesis, the students with dyslexia showed the same pattern of results as did the control participants, also in the LVF, apart from a slightly lower accuracy rate, particularly for the central letter. The latter is in line with the possibility of enhanced crowding in dyslexia. In addition, in the dyslexia group but not in the control group the degree of crowding correlated significantly with the students’ word reading scores. These findings suggest that lateral inhibition between letters is associated with word reading performance in students with dyslexia.
Keywords
SERIOL model, Lateral inhibition, PARAFOVEAL RECOGNITION, LETTER IDENTIFICATION, AVERAGE READERS, READING-SKILLS, HEMISPHERIC-DIFFERENCES, LATERAL MASKING, PHONOLOGICAL AWARENESS, ATTENTION SPAN DEFICIT, DEVELOPMENTAL DYSLEXIA, Dyslexia, INTERHEMISPHERIC INTERACTION, Visual word recognition, Letter position encoding, Crowding

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Citation

Please use this url to cite or link to this publication:

MLA
Callens, Maaike, Carol Whitney, Wim Tops, et al. “No Deficiency in Left-to-right Processing of Words in Dyslexia but Evidence for Enhanced Visual Crowding.” QUARTERLY JOURNAL OF EXPERIMENTAL PSYCHOLOGY 66.9 (2013): 1803–1817. Print.
APA
Callens, Maaike, Whitney, C., Tops, W., & Brysbaert, M. (2013). No deficiency in left-to-right processing of words in dyslexia but evidence for enhanced visual crowding. QUARTERLY JOURNAL OF EXPERIMENTAL PSYCHOLOGY, 66(9), 1803–1817.
Chicago author-date
Callens, Maaike, Carol Whitney, Wim Tops, and Marc Brysbaert. 2013. “No Deficiency in Left-to-right Processing of Words in Dyslexia but Evidence for Enhanced Visual Crowding.” Quarterly Journal of Experimental Psychology 66 (9): 1803–1817.
Chicago author-date (all authors)
Callens, Maaike, Carol Whitney, Wim Tops, and Marc Brysbaert. 2013. “No Deficiency in Left-to-right Processing of Words in Dyslexia but Evidence for Enhanced Visual Crowding.” Quarterly Journal of Experimental Psychology 66 (9): 1803–1817.
Vancouver
1.
Callens M, Whitney C, Tops W, Brysbaert M. No deficiency in left-to-right processing of words in dyslexia but evidence for enhanced visual crowding. QUARTERLY JOURNAL OF EXPERIMENTAL PSYCHOLOGY. 2013;66(9):1803–17.
IEEE
[1]
M. Callens, C. Whitney, W. Tops, and M. Brysbaert, “No deficiency in left-to-right processing of words in dyslexia but evidence for enhanced visual crowding,” QUARTERLY JOURNAL OF EXPERIMENTAL PSYCHOLOGY, vol. 66, no. 9, pp. 1803–1817, 2013.
@article{3218188,
  abstract     = {Whitney and Cornelissen hypothesized that dyslexia may be the result of problems with the left-to-right processing of words, particularly in the part of the word between the word beginning and the reader's fixation position. To test this hypothesis, we tachistoscopically presented consonant trigrams in the left and the right visual field (LVF, RVF) to 20 undergraduate students with dyslexia and 20 matched controls. The trigrams were presented at different locations (from –2.5° to + 2.5°) in both visual half fields. Participants were asked to identify the letters, and accuracy rates were compared. In line with the predictions of the SERIOL (sequential encoding regulated by inputs to oscillations within letter units) model of visual word recognition, a typical U-shaped pattern was found at all retinal locations. Accuracy also decreased the further away the stimulus was from the fixation location, with a steeper decrease in the LVF than in the RVF. Contrary to the hypothesis, the students with dyslexia showed the same pattern of results as did the control participants, also in the LVF, apart from a slightly lower accuracy rate, particularly for the central letter. The latter is in line with the possibility of enhanced crowding in dyslexia. In addition, in the dyslexia group but not in the control group the degree of crowding correlated significantly with the students’ word reading scores. These findings suggest that lateral inhibition between letters is associated with word reading performance in students with dyslexia.},
  author       = {Callens, Maaike and Whitney, Carol and Tops, Wim and Brysbaert, Marc},
  issn         = {1747-0218},
  journal      = {QUARTERLY JOURNAL OF EXPERIMENTAL PSYCHOLOGY},
  keywords     = {SERIOL model,Lateral inhibition,PARAFOVEAL RECOGNITION,LETTER IDENTIFICATION,AVERAGE READERS,READING-SKILLS,HEMISPHERIC-DIFFERENCES,LATERAL MASKING,PHONOLOGICAL AWARENESS,ATTENTION SPAN DEFICIT,DEVELOPMENTAL DYSLEXIA,Dyslexia,INTERHEMISPHERIC INTERACTION,Visual word recognition,Letter position encoding,Crowding},
  language     = {eng},
  number       = {9},
  pages        = {1803--1817},
  title        = {No deficiency in left-to-right processing of words in dyslexia but evidence for enhanced visual crowding},
  url          = {http://dx.doi.org/10.1080/17470218.2013.766898},
  volume       = {66},
  year         = {2013},
}

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