BIROn - Birkbeck Institutional Research Online

Selecting and ignoring salient objects within and across dimensions in visual search

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.
Official URL: http://dx.doi.org/10.1016/j.brainres.2009.05.077

Abstract

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.

Item Type: Article
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
Depositing User: Administrator
Date Deposited: 22 Dec 2010 14:08
Last Modified: 17 Apr 2013 12:19
URI: http://eprints.bbk.ac.uk/id/eprint/2518

Archive Staff Only (login required)

Edit/View Item Edit/View Item