Reading acquisition enhances an early visual process of contour integration

Authors

  • Marcin Szwed,

    1.  INSERM U992, Cognitive Neuroimaging Unit, IFR 49, Gif sur Yvette, France
    2.  Université Pierre et Marie Curie-Paris 6, Faculté de Médecine Pitié-Salpêtrière, Paris, France
    3.  CEA, NeuroSpin center, IFR 49, Gif sur Yvette, France
    4.  Université Paris XI, Orsay, France
    5.  Psychophysiology Laboratory, Institute of Psychology, Jagiellonian University, Kraków, Poland
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  • Paulo Ventura,

    1.  Faculty of Psychology, University of Lisbon, Portugal
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  • Luis Querido,

    1.  Faculty of Psychology, University of Lisbon, Portugal
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  • Laurent Cohen,

    1.  Inserm, ICM Research Center, U975, Paris, France
    2.  AP-HP, Groupe hospitalier Pitié-Salpêtrière, Department of Neurology, Paris, France
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  • Stanislas Dehaene

    1.  INSERM U992, Cognitive Neuroimaging Unit, IFR 49, Gif sur Yvette, France
    2.  Université Pierre et Marie Curie-Paris 6, Faculté de Médecine Pitié-Salpêtrière, Paris, France
    3.  CEA, NeuroSpin center, IFR 49, Gif sur Yvette, France
    4.  Université Paris XI, Orsay, France
    5.  Collège de France, Paris, France
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Marcin Szwed, Inserm-CEA Cognitive Neuroimaging Unit U992, CEA/NeuroSpin, Bat 145, Point Courrier 156, F-91191 GIF/YVETTE, France; e-mail: mfszwed@gmail.com

Abstract

The acquisition of reading has an extensive impact on the developing brain and leads to enhanced abilities in phonological processing and visual letter perception. Could this expertise also extend to early visual abilities outside the reading domain? Here we studied the performance of illiterate, ex-illiterate and literate adults closely matched in age, socioeconomic and cultural characteristics, on a contour integration task known to depend on early visual processing. Stimuli consisted of a closed egg-shaped contour made of disconnected Gabor patches, within a background of randomly oriented Gabor stimuli. Subjects had to decide whether the egg was pointing left or right. Difficulty was varied by jittering the orientation of the Gabor patches forming the contour. Contour integration performance was lower in illiterates than in both ex-illiterate and literate controls. We argue that this difference in contour perception must reflect a genuine difference in visual function. According to this view, the intensive perceptual training that accompanies reading acquisition also improves early visual abilities, suggesting that the impact of literacy on the visual system is more widespread than originally proposed.

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