Visual half-field symmetry in orientation perception.

The perception of orientation in the left and right visual half-fields has been investigated. No evidence for interfield differences was obtained for the discrimination of single lines by line matching or in magnitude of the systematic orientation distortion in orientation contrast and rod-and-frame experiments. Furthermore, increasing the time interval between test and comparison lines in successive matching provides no evidence for a differential operation of short-term spatial memory in the two hemispheres. It is concluded that hemispheric asymmetries do not arise at the level of sensory processing of spatial signals.