Ranking of Apparent Area for Different Shapes of Equal Area

St~mmasy.-36 figures of equal area but different form made up six form classes: triangles, quadrilarerals, polygons, ellipses, stars and irregular figures. 24 students presented with each set one at a time were asked to rank the figures from largest to smallest in perceived area. Next these Ss ranked sets including figures from the different shape classes, the sets being formed on the basis of ranks in the first task. Kendall's W and Friedman's x.' were significant for rankings within all sets suggesting consistent and differentiated influences of form on apparent area. Significant negative correlations between figure perimeter and ranks of estimated area in Exp. 1 and their absence in Exp. 2 suggested perimeter is related to apparent area with only certain sets of figures.