Letter identification in normal and dyslexic readers: A verification

Abstract

In a recent study, Geiger and Lettvin (1987) have reported that the Aubert-Foerster function— a decline in the identifiability of letters with increments in angular distance from the axis of gaze—is flatter in dyslexic than in normal readers. This study has received considerable criticism on methodological grounds. The present investigation, using more appropriate procedures, confirms Geiger and Lettvin’s findings. In two experiments, dyslexic and normal readers identified letters presented tachistoscopically at fixation or at 2.5°, 5.0°, and 7.5° to the right of fixation. In both experiments, normal readers’ accuracy of identification declined sharply between 5.0° and 7.5°, while the accuracy of the dyslexics did not decline from that achieved at fixation over the range of eccentricities employed. The results are probably not attributable to the dyslexics’ inability or unwillingness to follow fixation instructions. © 1989, Psychonomic Society, Inc.. All rights reserved.