Read Jenny C A, Cumming Bruce G
Laboratory of Sensorimotor Research, National Eye Institute, National Institutes of Health, Bethesda, MD, USA.
J Vis. 2005 May 17;5(5):417-34. doi: 10.1167/5.5.3.
In the Pulfrich effect, an illusion of depth is produced by introducing differences in the times at which a moving object is presented to the two eyes. In the classic form of the illusion, there is a simple explanation for the depth percept: the interocular delay introduces a spatial disparity into the stimulus. However, when the moving object is viewed stroboscopically, this simple explanation no longer holds. In recent years, depth perception in the stroboscopic Pulfrich effect has been explained by invoking neurons that are sensitive both to stereo disparity and to direction of motion. With such joint motion/disparity encoders, interocular delay causes a perception of depth by causing a shift in each neuron's preferred disparity. This model has been implemented by N. Qian and R. A. Andersen (1997). Here we show that this model's predictions for perceived disparity are quantitatively at odds with psychophysical measures. The joint-encoding model predicts that the perceived disparity is the virtual disparity implied by the apparent motion; in fact, the perceived disparity is smaller. We show that the percept can be quantitatively explained on the basis of spatial disparities present in the stimulus, which could be extracted from pure disparity sensors. These results suggest that joint encoding of motion and depth is not the dominant neuronal basis of depth perception in this stimulus.
在普尔弗里希效应中，通过使移动物体呈现给双眼的时间产生差异，会产生深度错觉。在该错觉的经典形式中，对于深度感知有一个简单的解释：双眼间延迟会在刺激中引入空间视差。然而，当以频闪方式观察移动物体时，这个简单的解释就不再成立了。近年来，频闪普尔弗里希效应中的深度感知是通过调用对立体视差和运动方向都敏感的神经元来解释的。有了这种联合运动/视差编码器，双眼间延迟通过引起每个神经元偏好视差的偏移而导致深度感知。这个模型已由钱南东和R.A.安德森（1997年）实现。在此我们表明，该模型对视差感知的预测在数量上与心理物理学测量结果不一致。联合编码模型预测，感知到的视差是由表观运动所暗示的虚拟视差；实际上，感知到的视差更小。我们表明，这种感知可以基于刺激中存在的空间视差进行定量解释，而这些空间视差可以从纯视差传感器中提取。这些结果表明，运动和深度的联合编码不是这种刺激中深度感知的主要神经基础。
