Mack Stephen C, Eckstein Miguel P
Vision & Image Understanding Laboratory, Department of Psychological and Brain Sciences, University of California, Santa Barbara, CA 93106, USA.
J Vis. 2011 Aug 19;11(9):1-16. doi: 10.1167/11.9.9.
There is accumulating evidence that scene context can guide and facilitate visual search (e.g., A. Torralba, A. Oliva, M. S. Castelhano, & J. M. Henderson, 2006). Previous studies utilized stimuli of restricted size, a fixed head position, and context defined by the global spatial configuration of the scene. Thus, it is unknown whether similar effects generalize to natural viewing environments and to context defined by local object co-occurrence. Here, with a mobile eye tracker, we investigated the effects of object co-occurrence on search performance under naturalistic conditions. Observers searched for low-visibility target objects on tables cluttered with everyday objects. Targets were either located adjacent to larger, more visible "cue" objects that they regularly co-occurred in natural scenes (expected condition) or elsewhere in the display, surrounded by unrelated objects (unexpected condition). Mean search times were shorter for targets at expected locations as compared to unexpected locations. Additionally, context guided eye movements, as more fixations were directed toward cue objects than other non-target objects, particularly when the cue was contextually relevant to the current search target. These results could not be accounted for by image saliency models. Thus, we conclude that object co-occurrence can serve as a contextual cue to facilitate search and guide eye movements in natural environments.
越来越多的证据表明，场景上下文可以引导并促进视觉搜索（例如，A. 托拉尔巴、A. 奥利瓦、M. S. 卡斯特利亚诺和J. M. 亨德森，2006年）。以往的研究使用的刺激具有受限的尺寸、固定的头部位置，以及由场景的全局空间配置定义的上下文。因此，尚不清楚类似的效果是否能推广到自然观看环境以及由局部对象共现定义的上下文。在此，我们使用移动眼动仪，研究了在自然条件下对象共现对搜索性能的影响。观察者在摆满日常物品的桌子上搜索低可见度的目标物体。目标物体要么位于与它们在自然场景中经常共现的较大、更显眼的“线索”物体相邻的位置（预期条件），要么位于显示器的其他位置，周围是不相关的物体（意外条件）。与意外位置的目标相比，预期位置的目标平均搜索时间更短。此外，上下文引导了眼动，因为更多的注视点指向线索物体而非其他非目标物体，特别是当线索与当前搜索目标在上下文上相关时。这些结果无法用图像显著性模型来解释。因此，我们得出结论，对象共现可以作为一种上下文线索，以促进自然环境中的搜索并引导眼动。
