Abstract
The confusion arising over judgements of the sizes of angular forms is described. Three experiments are reported. In the first, the apparent-sizes of acute and obtuse angles are estimated. In the second, judgements of the sizes assumed by upward- and downward- and left- and right-facing angles are compared. The third experiment is concerned with tactile reproduction of angles of specified sizes. In discussion an attempt is made to clarify the logical and empirical problems involved.