Tuning characteristics of the top-down attentional setting
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Tuning characteristics of the top-down attentional setting Fook K. Chua
Published online: 9 January 2013 # Psychonomic Society, Inc. 2012
Abstract Previous studies of top-down attentional guidance have focused generally on the attentional prioritization of a single target feature. The present study focused on how the attentional system would be configured when the target possesses several unique features. These features were perfectly correlated, which meant that monitoring just one of them would be an adequate strategy. The experiments addressed the following questions: (a) If the target is a singleton, would the attentional system be set to monitor the target’s unique features, or would the search strategy default to singleton detection? (b) Can the target’s static and dynamic features be prioritized simultaneously? (c) Are all of the target’s features prioritized, or only those features that are diagnostic of targethood? The results revealed an attentional system that can be flexibly tuned to multiple target features across static and dynamic dimensions. This system can simultaneously be narrowly tuned to monitor a specific target feature and broadly tuned to detect singletons. Finally, the attentional system monitors only those features that are diagnostic of targethood. Keywords Selective attention . Attentional capture Search for a salient object (e.g., a feature singleton among homogeneous distractors) is efficient, with search latencies roughly independent of display set size. This result has been extensively replicated and has formed the basis of many models of visual search (e.g., Treisman & Gelade, 1980; Wolfe, Cave, & Franzel, 1989), as well as of computational models of visual attention (e.g., Itti & Koch, 2000). One widely held conception is that, at the preattentive stage, the F. K. Chua (*) Department of Psychology, National University of Singapore, Kent Ridge Crescent, Singapore 119260, Singapore e-mail: [email protected]
saliency values of the visual scene are encoded in a twodimensional feature map. Fast, bottom-up mechanisms bias orienting toward the most salient location, and the saliency of a target that is a singleton will be high relative to the rest of the field. Thus, localizing the target is expected to be efficient because attention can be guided swiftly to its location, thereby allowing it to “pop out.” The question is whether this constitutes evidence of bottom-up attentional guidance. In the singleton-search experiment, saliency and targethood are perfectly correlated. However, for capture to be demonstrated unambiguously, it is essential that the experimental design ensure that the observer’s goal does not entail seeking the salient stimulus: That is, targethood and saliency have to be decoupled. Yantis and Egeth (1999) showed that when the object’s salient feature was not diagnostic of targethood, attention would not automatically be guided to it (but see Lamy & Zoaris, 2009, for a recent reevaluation). There appears, however, to be an exception. Yantis and his colleagues (e.g., Jo
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