Bacon W F, Egeth H E
Johns Hopkins University, Baltimore, Maryland.
Percept Psychophys. 1994 May;55(5):485-96. doi: 10.3758/bf03205306.
Theeuwes (1992) found a distracting effect of irrelevant-dimension singletons in a task involving search for a known target. He argued from this that selectivity is determined solely by stimulus salience; the parallel stage of visual processing cannot provide top-down guidance to the attentive stage sufficient to permit completely selective use of task-relevant information. We argue that in the task used by Theeuwes, subjects may have adopted the strategy of searching for an odd form even though the specific target form was known. In Experiment 1, we replicated Theeuwes's findings. Search for a circle target among diamond nontargets was disrupted by the presence of a diamond nontarget that was uniquely colored. In two subsequent experiments, we discouraged the singleton detection strategy, forcing subjects to search for the target feature. There was no distracting effect of a color singleton in these experiments, even with displays physically identical to those of Experiment 1, demonstrating that top-down selectivity is indeed possible during visual search. We conclude that goal-directed selection of a specific known featural identity may override stimulus-driven capture by salient featural singletons.
特乌韦斯（1992年）在一项涉及寻找已知目标的任务中发现了无关维度单一特征的干扰效应。他据此认为，选择性完全由刺激显著性决定；视觉处理的并行阶段无法为注意阶段提供足够的自上而下的指导，以允许完全选择性地使用与任务相关的信息。我们认为，在特乌韦斯所使用的任务中，尽管特定目标形状是已知的，但受试者可能采用了寻找奇异形状的策略。在实验1中，我们重复了特乌韦斯的研究结果。在菱形非目标中寻找圆形目标会受到一个颜色独特的菱形非目标的干扰。在随后的两个实验中，我们不鼓励单一特征检测策略，迫使受试者寻找目标特征。在这些实验中，即使显示与实验1的显示在物理上相同，颜色单一特征也没有干扰效应，这表明在视觉搜索过程中自上而下的选择性确实是可能的。我们得出结论，对特定已知特征身份的目标导向选择可能会超越显著特征单一特征的刺激驱动捕获。
