Cosman Joshua D, Vecera Shaun P
Department of Neuroscience, University of Iowa, Iowa City, IA, 52242-1407, USA.
Atten Percept Psychophys. 2011 May;73(4):996-1002. doi: 10.3758/s13414-011-0093-y.
Information held in visual working memory (VWM) influences the allocation of attention during visual search, with targets matching the contents of VWM receiving processing benefits over those that do not. Such an effect could arise from multiple mechanisms: First, it is possible that the contents of working memory enhance the perceptual representation of the target. Alternatively, it is possible that when a target is presented among distractor items, the contents of working memory operate postperceptually to reduce uncertainty about the location of the target. In both cases, a match between the contents of VWM and the target should lead to facilitated processing. However, each effect makes distinct predictions regarding set-size manipulations; whereas perceptual enhancement accounts predict processing benefits regardless of set size, uncertainty reduction accounts predict benefits only with set sizes larger than 1, when there is uncertainty regarding the target location. In the present study, in which briefly presented, masked targets were presented in isolation, there was a negligible effect of the information held in VWM on target discrimination. However, in displays containing multiple masked items, information held in VWM strongly affected target discrimination. These results argue that working memory representations act at a postperceptual level to reduce uncertainty during visual search.
视觉工作记忆（VWM）中存储的信息会影响视觉搜索过程中的注意力分配，与VWM内容匹配的目标比不匹配的目标在处理上更具优势。这种效应可能源于多种机制：首先，工作记忆的内容可能会增强目标的感知表征。或者，当目标出现在干扰项中时，工作记忆的内容可能会在感知后起作用，以减少目标位置的不确定性。在这两种情况下，VWM的内容与目标之间的匹配都应导致处理过程更加顺畅。然而，每种效应对于集合大小操作都有不同的预测；感知增强理论认为无论集合大小如何，处理都会更具优势，而不确定性降低理论则预测只有当集合大小大于1时才会有优势，因为此时目标位置存在不确定性。在本研究中，短暂呈现且被掩蔽的目标是单独呈现的，VWM中存储的信息对目标辨别几乎没有影响。然而，在包含多个掩蔽项目的显示中，VWM中存储的信息对目标辨别有强烈影响。这些结果表明，工作记忆表征在感知后层面起作用，以减少视觉搜索过程中的不确定性。
