Harris Julie M, Rushton Simon K
Department of Psychology, University of Newcastle upon Tyne, Henry Wellcome Building, Framlington Place, NE2 4HH, Newcastle, UK.
Vision Res. 2003 Feb;43(4):385-92. doi: 10.1016/s0042-6989(02)00570-9.
Under a variety of conditions, motion in depth from binocular cues is harder to detect than lateral motion in the frontoparallel plane. This is surprising, as the nasal-temporal motion in the left eye associated with motion in depth is easily detectable, as is the nasal-temporal motion in the right eye. It is only when the two motions are combined in binocular viewing that detection can become difficult. We previously suggested that the visibility of motion-in-depth is low because early stereomotion detectors average left and right retinal motions. For motion in depth, a neural averaging process would produce a motion signal close to zero. Here we tested the averaging hypothesis further. Specifically we asked, could the reduced visibility observed in previous experiments be associated with depth and layout in the stimuli, rather than motion averaging? We used anti-correlated random dot stereograms to show that, despite no depth being perceived, it is still harder to detect motion when it is presented in opposite directions in the two eyes than when motion is presented in the same direction in the two eyes. This suggests that the motion in depth signal is lost due to early motion averaging, rather than due to the presence of noise from the perceived depth patterns in the stimulus.
在各种条件下，与双眼线索相关的深度运动比额状平行平面中的横向运动更难被检测到。这很令人惊讶，因为与深度运动相关的左眼鼻颞向运动很容易被检测到，右眼的鼻颞向运动也是如此。只有当这两种运动在双眼观察中结合时，检测才会变得困难。我们之前曾提出，深度运动的可见性较低是因为早期的立体运动检测器对左右视网膜运动进行了平均。对于深度运动，神经平均过程会产生一个接近零的运动信号。在此，我们进一步测试了平均假说。具体而言，我们提出疑问：在之前的实验中观察到的可见性降低是否与刺激中的深度和布局有关，而非运动平均？我们使用反相关随机点立体图来表明，尽管没有感知到深度，但当运动在双眼以相反方向呈现时，比在双眼以相同方向呈现时更难被检测到。这表明深度运动信号是由于早期的运动平均而丢失，而非由于刺激中感知到的深度模式产生的噪声。
