Imaginal vs perceptual scanning of a visual representation.

Imaginal and perceptual scanning were compared to determine whether the reaction time function obtained during imaginal scanning in previous studies is analogous to what would happen in the perceptual situation. Subjects scanned arrays of four digits which were either imagined of physically present. Monotonic increases in reaction time as a function of distance were found in both cases. However, the zero intercept of the reaction times was significantly faster for the perceptual scanning group, probably due to the easier access to the loci. The over-all similarity in the results might suggest that a common structure is employed to represent information from imaginal and perceptual sources.