Influence of stimulus symmetry on visual scanning patterns

Eye movements of four Ss performing a complexity rating task in which the stimuli consisted of random shapes differing in symmetry, number of turns (sides) in the perimeter, and structural angularity were examined. It was found that for both symmetrical and asymmetrical shapes, the number of fixations and fixation time increased directly with structural complexity (number of sides). Distributions of fixations for symmetrical shapes clustered in one-half of the shapes, while the distributions of fixations for asymmetrical shapes did not exhibit this one-sided bias. No differences were found in the distributions of fixation time to either half of asymmetrical or symmetrical shapes. The findings suggest that S utilizes an organizing code in addition to the featural code in characterizing a given shape. The organizing code permits S to generate the feature code for a gwen shape on the basis of partial information.