Recognition of Form and of Orientation by Poor and Normal Readers

Abstract

Poor and normal readers were tested on two visual recognition tasks (N = 34). In both tasks, subjects were shown a random-dot pattern as a standard stimulus on each trial. After a 0.5-sec. or a 15-sec. interval (i.e., ‘perceptual’ versus ‘memory’ delay conditions), subjects were shown four patterns on a test slide and required to identify the one resembling the standard. This comparison was based on form identity in Task I and on form orientation in Task II. Recognition by poor and normal readers did not differ at at either delay on Task I or at the 0.5-sec. delay on Task II. No evidence of a generalized perceptual deficit among dyslexics was obtained. In general accordance with the theory of Corballis (1974), poor readers performed significantly worse than normals at the 15-sec. delay on Task II, indicating defective memory for orientation. More specific predictions of Corballis's theory were not borne out, however, with regard to the frequency of different types of error. Furthermore, up-down (rather than left-right) rotation errors appeared to be a better predictor of dyslexics' reading performance.