Perception of the upright in normal and schizophrenic subjects.

To see the effects of a large angle of frame-tilt, movement of the rod in the clockwise direction, and the difference between the normal and schizophrenic subjects in the perception of the upright, a mixed design (subjects X angle X presentation X trial) was used. 24 normal and 24 schizophrenic subjects were tested in a darkroom with a rod-and-frame test. The results showed a small error with a clockwise movement of the rod, when the frame also was tilted clockwise, and no difference in perception of the upright between the normal and schizophrenic subjects.