Berggren Nick, Eimer Martin
Department of Psychological Sciences, Birkbeck College, University of London, Malet Street, London, WC1E 7HX, UK.
Atten Percept Psychophys. 2020 Jul;82(5):2360-2378. doi: 10.3758/s13414-020-01977-5.
We investigated whether spatial filtering can restrict attentional selectivity during visual search to a currently task-relevant attentional window. While effective filtering has been demonstrated during singleton search, feature-based attention is believed to operate spatially globally across the entire visual field. To test whether spatial filtering depends on search mode, we assessed its efficiency both during feature-guided search with colour-defined targets and during singleton search tasks. Search displays were preceded by spatial cues. Participants responded to target objects at cued/relevant locations, and ignored them when they appeared on the uncued/irrelevant side. In four experiments, electrophysiological markers of attentional selection and distractor suppression (N2pc and P components) were measured for relevant and irrelevant target-matching objects. During singleton search, N2pc components were triggered by relevant target singletons, but were entirely absent for singletons on the irrelevant side, demonstrating effective spatial filtering. Critically, similar results were found for feature-based search. N2pcs to irrelevant target-colour objects were either absent or strongly attenuated (when these objects were salient), indicating that the feature-based guidance of visual search can be restricted to relevant locations. The presence of P components to salient objects on the irrelevant side during feature-based and singleton search suggests that spatial filtering involves active distractor suppression. These results challenge the assumption that feature-based attentional guidance is always spatially global. They suggest instead that when advance information about target locations becomes available, effective spatial filtering processes are activated transiently not only in singleton search, but also during search for feature-defined targets.
我们研究了空间滤波是否能在视觉搜索过程中将注意力选择性限制在当前与任务相关的注意力窗口内。虽然在单独项目搜索中已证明有效滤波的存在，但基于特征的注意力被认为在整个视野范围内进行空间全局操作。为了测试空间滤波是否依赖于搜索模式，我们在以颜色定义目标的特征引导搜索和单独项目搜索任务中评估了其效率。搜索显示之前会有空间线索。参与者对线索提示/相关位置的目标物体做出反应，而当目标物体出现在未提示/不相关一侧时则忽略它们。在四个实验中，针对相关和不相关的目标匹配物体测量了注意力选择和干扰项抑制的电生理标记（N2pc和P成分）。在单独项目搜索中，相关目标单独项目会触发N2pc成分，但不相关一侧的单独项目则完全不会触发，这表明存在有效的空间滤波。关键的是，在基于特征的搜索中也发现了类似结果。对于不相关的目标颜色物体，N2pc成分要么不存在，要么大幅减弱（当这些物体很突出时），这表明视觉搜索的基于特征的引导可以被限制在相关位置。在基于特征的搜索和单独项目搜索中，不相关一侧突出物体上P成分的存在表明空间滤波涉及主动的干扰项抑制。这些结果挑战了基于特征的注意力引导总是在空间上全局的假设。相反，它们表明当关于目标位置的预先信息可用时，有效的空间滤波过程不仅在单独项目搜索中，而且在搜索特征定义目标的过程中都会被短暂激活。
