Perceptual and lexical effects in letter identification: an event-related potential study of the word superiority effect.

Full Abstract

Most classical models of visual word recognition are based on sequentially organized levels of representation and involve feedback mechanisms to various extents. In this study, we aim at clarifying which of the early processing stages of visual word recognition are modulated by top-down lexical effects. We studied the identification of letters embedded in briefly presented words (e.g., TABLE) and illegal nonwords (e.g., GTFRS) using event-related potentials (ERPs). Participants were involved in the Reicher-Wheeler paradigm:
they were asked to indicate which of two letters displayed above and below a string of hashes was flashed immediately before at fixation within a letter string, which was either a word or a nonword. Event-related potentials were significantly modulated by the lexical status of stimuli around 200 ms after stimulus onset, i.e., in the peaking window of the N1 component. In light of our results, we propose that visual word form representations can constrain letter identification at a prelexical stage i.e., during the extraction of letter-shape information. In addition, we show that this facilitatory top-down effect is sensitive to stimulus exposure duration.

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Author information

Author/s: Martin, Clara D (CD); Nazir, Tatjana (T); Thierry, Guillaume (G); Paulignan, Yves (Y); Démonet, Jean-François (JF);

Affiliation: INSERM U455, Hôpital Purpan, F-31059, Toulouse Cedex, France. c.martin(-atsign-)bangor.ac.uk

Journal and publication information

Publication Type: Clinical Trial; Journal Article

Journal: Brain research (Brain Res), published in Netherlands. (Language: eng)

Reference: 2006-Jul; vol 1098 (issue 1) : pp 153-60

Dates: Created 2006/08/28; Completed 2006/10/24; Revised 2006/11/15;

PMID: 16774747, status: MEDLINE (last retrieval date: 12/26/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Adult
Electroencephalography
Electrophysiology
Evoked Potentials - physiology
Female
Functional Laterality - physiology
Humans
Male

Parietal Lobe - physiology
Psycholinguistics
Psychomotor Performance - physiology
Reaction Time
Reading
Recognition (Psychology) - physiology
Temporal Lobe - physiology
Visual Perception - physiology

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