V.S. Weiner, P.H. Schiller and Y.
Zhang, 2006
Vision Sci Soc Abstr., 404a,
Abstract
Using a random-dot display that makes it possible to provide disparity and motion
parallax cues separately or in combination, we examined how effectively these
two cues can be processed by monkeys and humans when contrast, size, and spatial
separation between target and background are systematically varied. Monkeys
and humans were trained to first fixate a central fixation spot and to then
make a saccadic eye movement to the target that appeared either singly in one
of four locations (detection task) or simultaneously with three identical distractors
(discrimination task). In monkeys correct choice was rewarded with a drop of
apple juice. Our results show the following: (1) Providing both disparity and
parallax cues yielded higher percent correct performance and shorter saccadic
latencies than when disparity or motion parallax cues were provided singly.
(2) Reducing the size and contrast of the display reduced performance more dramatically
for stereopsis than for motion parallax. (3) As spatial separation between the
background and the target was increased, performance fell off more dramatically
for motion parallax than for stereopsis. (4) When the stimuli were presented
at isoluminance, the deficit was more pronounced when the display was blue/yellow
than when it was red/green.
Our findings suggest that depth based on disparity cues is processed preferentially
by the midget system, whereas motion parallax cues are processed preferentially
by the parasol system. The koniocellular system that processes color information
in the blue/yellow domain appears to make a limited contribution to depth perception.
Citation: Weiner, V. S., Schiller, P. H., & Zhang, Y. (2006). How effective are disparity and motion parallax cues for depth perception in monkeys and humans? [Abstract]. Journal of Vision, 6(6):343, 343a, http://journalofvision.org/6/6/343/, doi:10.1167/6.6.343.