Department of Psychology and Logopedics, University of Helsinki, Siltavuorenpenger 1A, Helsinki, FI-00014, Finland.
School of Life & Health Sciences, Aston University, Birmingham, B4 7ET, United Kingdom.
Sci Rep. 2018 Jan 25;8(1):1593. doi: 10.1038/s41598-018-19464-1.
The locations of objects in our environment constitute arguably the most important piece of information our visual system must convey to facilitate successful visually guided behaviour. However, the relevant objects are usually not point-like and do not have one unique location attribute. Relatively little is known about how the visual system represents the location of such large objects as visual processing is, both on neural and perceptual level, highly edge dominated. In this study, human observers made saccades to the centres of luminance defined squares (width 4 deg), which appeared at random locations (8 deg eccentricity). The phase structure of the square was manipulated such that the points of maximum luminance gradient at the square's edges shifted from trial to trial. The average saccade endpoints of all subjects followed those shifts in remarkable quantitative agreement. Further experiments showed that the shifts were caused by the edge manipulations, not by changes in luminance structure near the centre of the square or outside the square. We conclude that the human visual system programs saccades to large luminance defined square objects based on edge locations derived from the points of maximum luminance gradients at the square's edges.
物体在我们环境中的位置可以说是我们的视觉系统必须传达的最重要信息之一，以促进成功的视觉引导行为。然而，相关物体通常不是点状的，也没有一个唯一的位置属性。相对较少的是已知的视觉系统如何代表这样的大型物体的位置，因为视觉处理在神经和感知水平上都是高度边缘主导的。在这项研究中，人类观察者向亮度定义的正方形（宽度 4 度）的中心进行扫视，这些正方形随机出现在（8 度的离轴距离）。正方形的相位结构被操纵，使得正方形边缘的最大亮度梯度点在试验之间移动。所有受试者的平均扫视终点都与这些变化惊人地定量一致。进一步的实验表明，这些变化是由边缘操纵引起的，而不是由正方形中心或外部的亮度结构变化引起的。我们的结论是，人类视觉系统根据正方形边缘上的最大亮度梯度点的边缘位置来规划对大亮度定义的正方形物体的扫视。
