Effect of orientation and of shape similarity on perceptual grouping

A method in which Os were asked to partition a pattern into two regions was used to investigate the perceptual grouping produced by changes in the orientation and shape of two-line figures. The results show that the judged similarity of the figures fails to predict the degree to which the figures form distinct perceptual groups. Grouping was most strongly influenced by differences in the orientation of the lines composing the figures. Crossing of lines making up the figures also affected grouping, but was less decisive than line orientation.