The present investigation was designed to examine a role of perceptual (Exp. I) and memory (Exp. II) processes on the occurrence of laterality effects. In Exp. I, the Ss made the "same or different" jugdement with respect to a pair of random farms which were successively presented to the right and left visual fields. The condition in which stimuli were presented to the right visual field first and to the left visual field second produced more errors than the converse condition. In Exp. II, the Ss formed matching judgements on a pair of forms which were serially presented to the same visual fields with a long delay interval. The right visual field condition produced more errors than the left visual field condition. This tendency was outstanding when the delay interval was comparatively long. The findings of the two experiments suggest that both factors, memory and perceptual, contribute to a laterality effect in the recognition of non-verbal materials.