Relative Height on the Picture-Plane and Depth Perception

Geometric considerations of the two-dimensional projection of the three-dimensional visual field led to hypotheses about the possible effect on depth perception of: relative height in the picture plane, the type of supplied reference plane, and angle of regard. In three experiments Ss viewed pairs of equidistant, horizontal rods in front of one of four backgrounds, with either an upward or downward angle of regard. The results confirm the hypothesis that relative height can operate to influence depth perception, that the type of background influences depth perception in the predicted direction, and that a response set resulting in a tendency for Ss to see higher objects as farther irrespective of the reference plane also occurs. The effects of angle of regard and of degree of vertical separation were not completely elucidated.