Bottom-up guidance in visual search for conjunctions
Keywords:attention, visual search, bottom-up, top-down, conjunction
Deposited by:Dr. Michael J. Proulx
Date of Issue:2006
Journal/Publication Title:Journal of Experimental Psychology: Human Perception and Performance
Abstract:Understanding the relative role of top-down and bottom-up guidance is crucial for models of visual search. Previous studies have addressed the role of top-down and bottom-up processes in search for a conjunction of features, but with inconsistent results. Here an attentional-capture method was used to address the role of top-down and bottom-up processes in conjunction search. The role of bottom-up processing was assayed by including an irrelevant size singleton in a search for a conjunction of color and orientation. One object was uniquely larger on each trial, with chance probability of coinciding with the target; thus the irrelevant feature of size was not predictive of the target’s location. Subjects searched more efficiently for the target when it was also the size singleton and less efficiently for the target when a nontarget was the size singleton. Although a conjunction target cannot be detected on the basis of bottom-up processing alone, subjects utilized search strategies that relied significantly on bottom-up guidance to find the target, resulting in interference from the irrelevant size singleton.