Speed of size scaling in human vision

Ss compared the forms of pairs of rapidly presented rectangles. The rectangles varied in size and frontal plane orientation. The speed of mental size scaling was estimated from the relationship of judgment time to the size discrepancy between the rectangles. In addition, the speed of mental rotation was estimated by the increase in judgment time produced by a discrepancy between the orientations of the rectangles. Size scaling and mental rotation seem to be largely independent of one another.