• Korean Journal of Cognitive Science
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• v.16 no.4
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• pp.243-254
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• 2005

Pulfrich effect implies the possibility that motion information is processed by the system that processes depth information, and this possibility by supported by various neurophysiological studies. Although Pulfrich effect is processed by the system that processes binocular disparity, the representative depth information, there has not been a psychophysical research to determine the characteristics of the interaction between Pulfrich effect and binorular disparity using a stimulus containing the two information sources. Present research examined the characteristics of the interacation between Pulfrich effect and binocular disparity by nenuring the depth and rotation direction of a rotating cylinder comprised of random dots under two different conditions: 1) consistent rendition where the Pulfrich effect and binocular disparity depth the depth and rotation direction of the cylinder in a consistent manner 2) inconsistent rendition where they did not. , The perceived depth of the cylinder in the consistent condition was larger than that in disparity/Pulfrich effect only condition. Interestingly, the perceived rotation direction of the cylinder in the inconsistent condition was modulated by the relative strength of the disparity and the Pulfrich effect. These results imply that binocular disparity and Pulfrich effect are processed by a common neurophysiological methanism.

• Korean Journal of Cognitive Science
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• v.18 no.3
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• pp.223-244
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• 2007

Two well known mis-localization effects, flash-lag effect (FLE) and the Pulfrich effect, have similar phenomena and theoretical explanations. In order to directly compare two phenomena, thereby examining the possibility that two phenomena have a common mechanism, the magnitudes of two effects were measured under the same experimental settings and stimuli. The Pulfrich depth was measured from each of four different brightness ratios of two moving stimuli, each of which was projected to each eye. The magnitude of FLE was measured from each of five different brightness levels, which were the same levels used in the Pulfrich experiment. The Pulfrich depth was increased with the increase of brightness ratio, whereas similar pattern was not found in the magnitude of FLE. Furthermore, actual Pulfrich depths were greatly different from those predicted from the difference of two FLEs. These results suggest that two phenomena may not have a common mechanism.