Hemispheric differences for global and local processing: effect of stimulus size and sparsity

The present experiment was designed to assess the hemispheric differences for global and local processing in healthy participants under different conditions of stimuli visibility, by means of varying the size and sparsity. Three different sizes and three different matrixes of hierarchical stimuli were introduced. Stimuli consisted of incomplete squares with one side missing. Participants were asked to carry out an orientation classification task (left/right), indicating the orientation of the square opening either at global or local levels. The results do not support the hemispheric differences for global and local processing, showing the same efficiency of right and left hemispheres for analyzing global and local information. Nevertheless, other results found are consistent with the hypothesis of right hemisphere superiority under degraded stimulus conditions.