Feldmann-Wüstefeld Tobias, Schubö Anna
Experimental and Biological Psychology, Philipps-University, Marburg, Germany.
J Vis. 2013 May 6;13(3):11. doi: 10.1167/13.3.11.
Homogeneous contexts were shown to result in prioritized processing of embedded targets compared to heterogeneous contexts (Duncan & Humphreys, 1989). The present experiment used behavioral and ERP measures to examine whether context homogeneity affects both enhancing relevant information and inhibiting irrelevant in contexts of varying homogeneity. Targets and distractors were presented laterally or on the vertical midline which allowed disentangling target- and distractor-related activity in the lateralized ERP (Hickey, diLollo, & McDonald, 2009). In homogeneous contexts, targets elicited an NT component from 150 ms on and a PD component from 200 ms on, showing early attention deployment at target locations and active suppression of distractors. In heterogeneous contexts, an NT component was also found from 150 ms on and PD was found from 250 ms on, suggesting delayed suppression of the distractor. Before 250 ms, distractors in heterogeneous contexts elicited a contralateral negativity, indicating attentional capture of the distractor prior to active suppression. In sum the present results suggest that top-down control of attention is more pronounced in homogeneous than in heterogeneous contexts.
与异质情境相比，同质情境会导致对嵌入目标的优先加工（邓肯和汉弗莱斯，1989）。本实验采用行为和事件相关电位（ERP）测量方法，来检验情境同质性是否会在不同同质性情境中，既增强相关信息又抑制无关信息。目标和干扰项呈现在视野一侧或垂直中线上，这使得能够在偏侧化ERP中区分与目标和干扰项相关的活动（希基、迪洛洛和麦克唐纳，2009）。在同质情境中，目标从150毫秒开始引发一个NT成分，从200毫秒开始引发一个PD成分，表明在目标位置早期就进行了注意力分配，并对干扰项进行了主动抑制。在异质情境中，从150毫秒开始也发现了一个NT成分，从250毫秒开始发现了PD成分，这表明对干扰项的抑制延迟。在250毫秒之前，异质情境中的干扰项引发了对侧负波，表明在主动抑制之前干扰项引起了注意力捕获。总之,目前的结果表明，自上而下的注意力控制在同质情境中比在异质情境中更明显。
