A cerebral origin for "directionality".

The cerebral origin of a directional bias in visual perception has proved difficult to ascertain. By means of a brief and reliable visuographic task, from which is derived an index of directionality (D), distributions of directional bias are shown to be related to handedness, as well as to other variables usually associated with cerebral lateralization. Familial sinistrality, gender, and age also influence the direction of bias.