Tsui Sum Yin, Khuu Sieu K, Hayes Anthony
Department of Psychology, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
Vision Res. 2007 Jan;47(1):8-15. doi: 10.1016/j.visres.2006.09.004. Epub 2006 Oct 27.
Motion signals contained within a stationary object projected on the fronto-parallel plane shift the object's apparent spatial position in the direction of the motion [see De Valois, R. L., & De Valois, K. K. (1991). Vernier acuity with stationary moving Gabors. Vision Research, 31(9), 1619-1626]. We report an analogous apparent position shift of three-dimensional objects that contain local elements that move in depth. Our stimulus was a transparent three-dimensional cylinder defined by 150 limited-lifetime dots, oriented such that it was end on and its tangent plane was circular. Dots moved in depth by changes in their binocular disparities. In the first experiment, observers judged the positions of the near and far ends of the cylinder, by moving marker lines in depth, for different dot speeds. The results showed that when dots moved towards the observer, the perceived location of the two ends of the cylinder appeared closer in depth. When dots moved away from the observer, the opposite effect was produced. Additionally, the amount of apparent position shift produced was dependent on dot speed, with faster speeds producing larger positional offsets. However, we found in the second experiment that when the cylinder contained randomly moving dots, or when the cylinder contained equal amounts of dots moving towards and away from the observer, positional shifts were very much reduced, or abolished. Our findings suggest that motion signals can induce a misperception of position in depth that is similar manner to that produced by motion within an object in the two-dimensional image plane.
投射在额状平行面上的静止物体所包含的运动信号会使物体的视空间位置在运动方向上发生偏移[见德瓦洛伊斯，R. L.，& 德瓦洛伊斯，K. K.（1991年）。静止移动的高斯包络的游标视力。《视觉研究》，31(9)，1619 - 1626]。我们报告了三维物体的类似视位置偏移，这些三维物体包含在深度上移动的局部元素。我们的刺激物是一个由150个有限寿命的点定义的透明三维圆柱体，其定向使得它的一端朝向观察者且其切平面是圆形的。点通过双眼视差的变化在深度上移动。在第一个实验中，观察者通过在深度上移动标记线来判断圆柱体近端和远端的位置，针对不同的点速度。结果表明，当点朝着观察者移动时，圆柱体两端的感知位置在深度上显得更近。当点远离观察者移动时，会产生相反的效果。此外，产生的视位置偏移量取决于点的速度，速度越快，位置偏移越大。然而，我们在第二个实验中发现，当圆柱体包含随机移动的点时，或者当圆柱体包含等量朝着和远离观察者移动的点时，位置偏移会大大减少或消除。我们的研究结果表明，运动信号可以在深度上引起位置的错误感知，其方式与二维图像平面中物体内的运动所产生的错误感知相似。
