Warren Paul A, Rushton Simon K
School of Psychology, Tower Building, Cardiff University, Cardiff, Wales, UK.
J Vis. 2007 Aug 16;7(11):2.1-11. doi: 10.1167/7.11.2.
A moving observer needs to be able to estimate the trajectory of other objects moving in the scene. Without the ability to do so, it would be difficult to avoid obstacles or catch a ball. We hypothesized that neural mechanisms sensitive to the patterns of motion generated on the retina during self-movement (optic flow) play a key role in this process, "parsing" motion due to self-movement from that due to object movement. We investigated this "flow parsing" hypothesis by measuring the perceived trajectory of a moving probe placed within a flow field that was consistent with movement of the observer. In the first experiment, the flow field was consistent with an eye rotation; in the second experiment, it was consistent with a lateral translation of the eyes. We manipulated the distance of the probe in both experiments and assessed the consequences. As predicted by the flow parsing hypothesis, manipulating the distance of the probe had differing effects on the perceived trajectory of the probe in the two experiments. The results were consistent with the scene geometry and the type of simulated self-movement. In a third experiment, we explored the contribution of local and global motion processing to the results of the first two experiments. The data suggest that the parsing process involves global motion processing, not just local motion contrast. The findings of this study support a role for optic flow processing in the perception of object movement during self-movement.
移动的观察者需要能够估计场景中其他移动物体的轨迹。如果没有这种能力，就很难避开障碍物或接住球。我们假设，对自我运动（光流）过程中在视网膜上产生的运动模式敏感的神经机制在这个过程中起着关键作用，将由于自我运动产生的运动与由于物体运动产生的运动“区分”开来。我们通过测量放置在与观察者运动一致的流场中的移动探针的感知轨迹，来研究这种“流区分”假设。在第一个实验中，流场与眼球旋转一致；在第二个实验中，它与眼球的横向平移一致。我们在两个实验中都操纵了探针的距离，并评估了其后果。正如流区分假设所预测的那样，在两个实验中操纵探针的距离对探针的感知轨迹产生了不同的影响。结果与场景几何形状和模拟自我运动的类型一致。在第三个实验中，我们探讨了局部和全局运动处理对前两个实验结果的贡献。数据表明，区分过程涉及全局运动处理，而不仅仅是局部运动对比。这项研究的结果支持了光流处理在自我运动过程中物体运动感知中的作用。
