Dependence of Speed and Direction Perception on Cinematogram Dot Density
Conducted 3 experiments with a total of 5 Ss (including 1 of the authors) to examine how changes of dot density affect perceived speed and direction and speed discrimination of random-dot cinematograms. With abrupt decreases in dot density of random-dot cinematograms, perceived speed decreased, while with abrupt increases in dot density, perceived speed increased. Further, in steady-state conditions, perceived speed was also affected in the same way, but to a lesser degree, by the dot density of cinematograms. Direction discrimination of random-dot cinematograms was enhanced when dot density increased abruptly from one stimulus to the next but was degraded when dot density decreased abruptly. Finally, speed discrimination remained constant even when density changed abruptly. The perceived-speed and direction-discrimination data are consistent with the motion coherence theory.
Watamaniuk, S. N.,
Grzywacz, N. M.,
& Yuille, A. L.
(1993). Dependence of Speed and Direction Perception on Cinematogram Dot Density. Vision Research, 35 (5-6), 849-859.