Perceptual grouping produced by line figures

Two experiments, one with 2 and one with 3-line figures, studied the relative effectiveness of differences in orientation and shape in producing grouping by Similarity. The results showed that changes in shape or orientation which leave the component lines of the figures vertical and horizontal do not facilitate grouping as readily as changes which alter the direction of the component lines to 45° and 135°. These results corroborate and extend the findings of Beck (l966a, 1966b) and are discussed in relation to the problem of specifying the properties of line figures that produce grouping by similarity.