Visual processing of depth and motion in synthetic visual displays

The ability to perceive the trajectory of an object moving through three-dimensional space (called motion-in-depth perception) is based, in part, on dynamic binocular parallax information. Recent analysis(1) shows that the perception of motion-in-depth should be affected by viewing distance information. With other factors held constant, short viewing distances should produce trajectories which are seen as flatter, while long viewing distances should produce trajectories which appear directed more toward the observer. The present study investigated whether such an effect of viewing distance actually occurs. On a synthetic visual display, observers viewed a stereoscopic stimulus moving through three-dimensional space. Two viewing distances were established and observers matched the perceived trajectory of the stimulus at each distance, Results showed that the trajectory of the stimulus was seen as flatter at the short viewing distance, while its trajectory appeared more toward the observer at the long distance. Thus, viewing distance should be considered an important factor affecting the trajectory of moving simulated objects in synthetic visual displays.