Learning to read undoubtedly involves some measure of perceptual learning. A child has to learn to discriminate between visually similar shapes and to perceive initially unfamiliar patterns that have to be associated with the sounds making up words (see Samuels & Anderson, 1973). It is perhaps not surprising, therefore, that at one time it was common (see Vellutino, 1979) to think of dyslexia as involving a difficulty in intersensory (cross-modal) integration (Beaumont, Thomson, & Rugg, 1981; Birch & Belmont, 1964; Gooddy & Reinhold, 1961) or some form of visuo-perceptual impairment (see Ingram, 1963; Lovell et al., 1964; Silver & Hagin, 1964; Vellutino, 1979; Vernon, 1957), although the precise nature of the putative perceptual deficit was rarely made explicit (Stanovich, 1988a). Indeed, the suggestion of a visuo-perceptual impairment was often made purely on the basis of relatively poor performance on visuo-constructive tasks or performance sub-tests of intelligence scales. Hermann (1959) held that “difficulties in reading and writing can be viewed as the result of an impairment of Gestalt function…which is impeded…because there is primarily a disturbance of directional function” (p. 144). The latter he treated “primarily as a matter of optic-spatial orientation”, while admitting the involvement of “chronological aspects, especially in relation to sequence” (p. 145). Drew (1956) regarded the dyslexia shown by three members of the same family as “due to a basic defect in Gestalt recognition which interferes with visual-verbal comprehension” (p. 457).