The effects of stimulus complexity and sensory modality on reaction time in normal and retarded readers.

Intra- and crossmodal performance of normal and retarded readers was compared in a reaction-time task. Both reading groups showed slower crossmodal than intramodal shifting. This effect occurred equally for both reading groups. Differences between the two groups occurred, however, when a complex visual stimulus was present. The complex stimulus resulted in the retarded readers showing slower reaction times to other stimuli in that setting. This effect occurred for stimuli both within and across modalities. The results suggested that the demands of stimulus complexity within the visual modality rather than the demands of crossmodal shifting were related to reading ability.