Schubo, A. and Muller, Hermann J. (2009) Selecting and ignoring salient objects within and across dimensions in visual search. Brain Research 1283 , pp. 84-101. ISSN 0006-8993.Full text not available from this repository.
There are two strategies for selecting relevant information from a visual scene: according to either its salience or its relevance for behavioral goals. Although there is broad evidence for the existence of both mechanisms, there has been a debate concerning the impact of top-down control on salience-based selection. We investigated whether salient but irrelevant information is filtered by the visual system and what role the organization of the visual system plays in selection. Using event-related brain potentials (ERPs), we compared processing of the same salient objects when relevant versus irrelevant to the task at hand. Observers had to detect a target singleton defined in a specific dimension (e.g., orientation), while ignoring a singleton non-target defined in either another dimension (e.g., color; Experiment 1, requiring dimension-based search) or the same dimension (Experiment 2, requiring feature-based search). For dimension-based search, the results revealed an enhanced posterior N2, indicative of singleton selection, and an enhanced P3 for target singletons, but no difference between non-target singletons defined in another dimension and blank trials. Also, N2pc results indicated that the allocation of attention was modulated by the task. In contrast, for feature-based search, some ERP enhancement was also observed for non-target singletons (defined in the same dimension as the target) in the N2, N2pc, and P3 latency ranges. This pattern argues in favor of a strong top-down influence on singleton selection that operates on dimensions rather than features.
|Keyword(s) / Subject(s):||Attention guidance, bottom-up selection, top-down selection, dimension-specific processing, posterior N2, N2pc|
|School or Research Centre:||Birkbeck Schools and Research Centres > School of Science > Psychological Sciences|
|Date Deposited:||22 Dec 2010 14:08|
|Last Modified:||17 Apr 2013 12:19|
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