Abstract
In order to investigate the anisotropy and individual differences in depth perception, we measured magnitude and direction of perceived depth based on disparity and motion parallax using a matching method. The stimulus was a random-dot pattern, subtended 20 deg by 20 deg, which was displayed on a monitor screen. The disparity or motion parallax was modulated sinusoidally with 0.05 c/deg along a horizontal or vertical meridian, simulating a concave or convex depth surface of 1, 4, or 10 cm peak-to-trough depth amplitude. An observer was required to adjust a curved line on the monitor screen so that its shape appeared to match that of the perceived depth surface. For the disparity-defined depth, five of ten observers perceived veridical depth. Two other observers significantly underestimated the magnitude of depth along the horizontal meridian. In that condition, the remaining three observers perceived depth in opposite direction to the geometrical prediction. For the motion parallax-defined depth, we did not find significant anisotropy or individual differences. These results suggest that there is a disparity-specific process which causes anisotropy although there might be common processes to produce depth for these cues.