Berggren Nick, Eimer Martin
Department of Psychological Sciences, Birkbeck College, University of London, Malet Street, London, WC1E 7HX, UK.
Department of Psychological Sciences, Birkbeck College, University of London, Malet Street, London, WC1E 7HX, UK.
Biol Psychol. 2018 Apr;134:1-8. doi: 10.1016/j.biopsycho.2018.02.007. Epub 2018 Feb 16.
Feature-based control processes guide attention towards objects with target features in visual search. While these processes are assumed to operate globally across the entire visual field, it remains controversial whether target-matching objects at task-irrelevant locations can be excluded from attentional selection, especially when spatial attention is already narrowly focused elsewhere. We investigated whether probe stimuli at irrelevant lateral locations capture attention when they precede search displays where targets are defined either by a specific feature (colour or orientation) or by a colour/orientation conjunction by measuring N2pc components (an electrophysiological marker of attentional target selection) to these probes. Reliable N2pcs were triggered by probes not only in the feature search tasks but also when participants searched for feature conjunctions, in spite of the fact that conjunction search requires focal spatial attention. Analogous N2pc results were found in the absence of any spatial uncertainty about the location of conjunctively defined targets, which always appeared at fixation. These results show that rapid attentional capture by objects with target-matching features cannot be prevented by top-down spatial filtering mechanisms, and confirm that feature-based attentional guidance processes operate in a spatially global fashion.
基于特征的控制过程在视觉搜索中引导注意力指向具有目标特征的物体。虽然这些过程被认为在整个视野中全局运作，但任务无关位置上与目标匹配的物体是否能被排除在注意选择之外仍存在争议，尤其是当空间注意力已经狭窄地聚焦在其他地方时。我们通过测量对这些探测刺激的N2pc成分（一种注意目标选择的电生理指标），来研究当探测刺激出现在搜索显示之前时，无关横向位置的探测刺激是否会吸引注意力，在搜索显示中目标由特定特征（颜色或方向）或颜色/方向联合定义。可靠的N2pc不仅在特征搜索任务中由探测刺激触发，而且在参与者搜索特征联合时也会触发，尽管联合搜索需要聚焦的空间注意力。在联合定义的目标位置不存在任何空间不确定性（目标总是出现在注视点）的情况下，也发现了类似的N2pc结果。这些结果表明，具有目标匹配特征的物体所引发的快速注意捕获不能被自上而下的空间过滤机制所阻止，并证实基于特征的注意引导过程以空间全局的方式运作。
