Experimental Studies of a Perceptual Anomaly

Abstract
The experiment to be reported in this paper stems from previous work on the block design rotation effect (Shapiro, 2, 3, 4; Yates, 9, 10; Williams, Lubin et al., 7). As is well known, the block design test in its various forms: Kohs, Wechsler and Goldstein Scheerer, requires the subject to reproduce, with one-inch multi-coloured cubes, a series of abstract designs. It has been reported by a number of observers that subjects sometimes leave their reproductions in a rotated position, although otherwise the designs have been correctly reproduced.