Orientation bias in the Rod-and-Frame Test.

Rod-and-frame data for a sample of 21 males and 25 females showed marked asymmetries in the magnitudes of the frame effects for left and right frame-tilt. These asymmetries are interpreted as an underlying tendency for individuals to set the rod systematically clockwise or counterclockwise of true vertical, independently of the influence of the visible frame, and the term "orientation bias" is used to describe this tendency. 14 males and 14 females demonstrated orientation biases significantly different from zero. In group comparisons males differed significantly from females, the mean bias for males as a group lying significantly left (counterclockwise) of vertical while the mean for females as a group did not differ from zero. Implications for conventional measures of field dependence are discussed. Possible diagnostic significance of orientation performance for brain injury is also considered, and an unusual individual performance is described.