CAN CERTAIN STIMULUS CHARACTERISTICS INFLUENCE THE HEMISPHERIC-DIFFERENCES IN GLOBAL AND LOCAL PROCESSING

Hemispheric processing of global and local form was examined in two experiments in which the size of hierarchical visual stimuli was manipulated in divided-attention tasks. In experiment 1, the subjects were instructed to decide whether or not a symmetrical target (T) was in the visual object presented. In experiment 2, the target to be detected was nonsymmetrical (L). In both studies, global precedence was found depending on stimulus size. When the stimuli subtended about 3-degrees vertically, global dominance was found, but it was not detected when the stimuli subtended about 10-degrees. Experiments 1 and 2 provided evidence against the analytic/holistic dichotomy, presenting the same performance for both hemispheres: the global analysis was much better than the local analysis. When the target was in the global form, both the LH and the RH analyzed the 3-degrees stimuli more efficiently, while both analyzed the 10-degrees stimuli with greater efficiency when the target was in the local form.