Westheimer G
Department of Molecular and Cell Biology, University of California, Berkeley 94720.
Vision Res. 1990;30(11):1913-21. doi: 10.1016/0042-6989(90)90167-j.
When it is surrounded by lines of a differing orientation, a test line changes its apparent orientation in a direction away from that of the surround lines. Using a nulling technique to arrive at numerical values, the properties of this simultaneous orientation contrast have been analyzed: it diminishes with distance of the surround lines; rises and then falls off as a function of surround line orientation; decreases with exposure duration; is sharply tuned (+/- 100 msec) for synchrony of test and surround line presentation; is robust to differences between test and surround line disparity but not intensity; and is reduced with dichoptic presentation of test and surround lines. Orientation contrast can be induced in a variety of oriented features, including illusory contours, an ellipse, a moving dot and a row of dots or lines, but two dots alone don't suffice. The results are taken as evidence that orientation is a domain sui generis, in which simultaneous contrast is exhibited in the same manner as in the domains of color, brightness and disparity.
当测试线被不同方向的线条包围时，它会朝着远离包围线方向的方向改变其视在方向。利用归零技术得出数值，对这种同时性方向对比度的特性进行了分析：它会随着包围线距离的增加而减弱；随着包围线方向的变化先上升后下降；随着曝光持续时间的增加而降低；对测试线和包围线呈现的同步性有敏锐的调谐（±100毫秒）；对测试线和包围线视差之间的差异具有鲁棒性，但对强度差异不具有鲁棒性；并且当测试线和包围线进行双眼分视呈现时会降低。方向对比度可以在各种有方向的特征中诱发，包括虚幻轮廓、椭圆、移动的点以及一排点或线，但仅两个点是不够的。这些结果被视为方向是一个独特领域的证据，在该领域中，同时性对比度的表现方式与颜色、亮度和视差领域相同。
