Zhaoping Li
Department of Computer Science, University College London, UK.
J Vis. 2012 Feb 17;12(2):17. doi: 10.1167/12.2.17.
Where we look in visual tasks is determined by both bottom-up and top-down factors. One theory (Li, 1999a, 2002) suggests that visual area V1 creates a bottom-up saliency map, guiding gaze through extensive projections to the superior colliculus. V1 is the only visual cortical area that represents the eye of origin of an input and is also least associated with awareness; I therefore predicted that an ocular singleton (i.e., an item only shown to one eye among other items shown to the other eye) that is perceptually indistinct might nevertheless attract gaze. In visual searches for an orientation singleton target bar among uniformly oriented background bars, an ocular singleton non-target bar, at the same eccentricity as the target from the center of the search display, often captured the first search saccade. The chance of this capture was above 50% (e.g., 75%) when the eccentricity of the singletons was large and luminance did not vary between the bars, and it was below 50% when the eccentricity was smaller and luminance varied. After each search trial, observers reported whether an ocular singleton non-target (which was actually presented in half of the trials) had been shown. When different bars had similar luminance, misses numbered less than 50% and were independent of whether the gaze was captured by the ocular singleton. However, when luminance varied sufficiently between the bars, 50% were missed overall, albeit significantly less for those that captured gaze. The experiments in this work followed the guidelines in the Declaration of Helsinki.
我们在视觉任务中的注视位置由自下而上和自上而下的因素共同决定。一种理论（Li，1999a，2002）认为，视觉区域V1创建一个自下而上的显著性地图，通过广泛投射到上丘来引导注视。V1是唯一代表输入来源眼的视觉皮层区域，并且与意识的关联也最小；因此我预测，一个在感知上不清晰的单眼独特刺激（即，在其他项目展示给另一只眼时，只有一个项目展示给一只眼）可能仍然会吸引注视。在均匀定向的背景条中视觉搜索一个定向独特刺激目标条时，一个与搜索显示中心的目标具有相同偏心率的单眼独特刺激非目标条，常常会捕捉到首次搜索扫视。当独特刺激的偏心率较大且条之间的亮度没有变化时，这种捕捉的概率超过50%（例如75%），而当偏心率较小时且亮度有变化时，该概率低于50%。在每次搜索试验后，观察者报告是否展示了一个单眼独特刺激非目标（实际上在一半的试验中呈现）。当不同的条具有相似亮度时，漏报次数少于50%，并且与注视是否被单眼独特刺激捕捉无关。然而，当条之间的亮度变化足够大时，总体漏报率为50%，尽管对于那些捕捉到注视情况的漏报率明显更低。本研究中的实验遵循了《赫尔辛基宣言》中的指导原则。
