Stuit Sjoerd M, Verstraten Frans A J, Paffen Chris L E
Utrecht University, Neuroscience & Cognition Utrecht, Helmholtz Institute, Division of Experimental Psychology, Heidelberglaan 2, NL-3584 CS, Utrecht, The Netherlands.
Vision Res. 2010 Sep 15;50(19):1913-21. doi: 10.1016/j.visres.2010.06.014. Epub 2010 Jul 3.
During binocular rivalry, perception alternates between dichoptically presented incompatible images. With larger images, such perceptual alternations will typically start locally and then gradually spread across the image, known as traveling waves of perceptual dominance. Several image-features (such as local contrast) are known to determine where in the image a traveling wave originates. Here we investigate whether orientation contrast in the suppressed image affects these spatial origin(s) of perceptual alternations. The results show that the origins are increasingly biased towards locations of increasing orientation contrast in the suppressed image. This increase in bias is related to the efficiency of visual search for the orientation contrast, tested offline: we find large biases towards orientation contrast when visual search for it is efficient, and small biases when search for it is inefficient. Our results imply that rivalry suppression is not homogenous across the suppressed image, but is dependent on local image-features in the suppressed image. The relation between spatial bias and visual search performance suggests that spatial origins of perceptual alternations are biased to salient locations in the suppressed image. Moreover, the finding that saliency affects the spatial origin of a perceptual alternation is in agreement with the idea that saliency is represented at a monocular, unconscious level of visual processing.
在双眼竞争期间，感知在双眼分别呈现的不相容图像之间交替。对于较大的图像，这种感知交替通常会从局部开始，然后逐渐在整个图像中传播，这被称为感知优势的行波。已知几种图像特征（如局部对比度）可决定图像中行波的起始位置。在此，我们研究被抑制图像中的方向对比度是否会影响感知交替的这些空间起始位置。结果表明，这些起始位置越来越偏向于被抑制图像中方向对比度增加的位置。这种偏差的增加与离线测试的视觉搜索方向对比度的效率有关：当对方向对比度的视觉搜索效率高时，我们发现对其有较大偏差；而当搜索效率低时，偏差较小。我们的结果表明，竞争抑制在被抑制图像中并非均匀分布，而是取决于被抑制图像中的局部图像特征。空间偏差与视觉搜索性能之间的关系表明，感知交替的空间起始位置偏向于被抑制图像中的显著位置。此外，显著性影响感知交替的空间起始位置这一发现与显著性在单眼、无意识视觉处理水平上得到表征的观点一致。
