Visual Search and Attention A Signal Detection Theory Approach

combination of features; the target cannot be characterized by a single unique attribute. An example of a conjunction search task is a target that is a bright vertical Background Visual search is an everyday task. One might search for line among distractors that are dark vertical lines and bright tilted lines. Neither brightness nor orientation a familiar face in a crowd, or a memo on a cluttered desktop. The ease of search depends chiefly on how alone defines the target uniquely. Treisman and Gelade (1980) suggest that the second limited-capacity stage, distinguishable the target of search is from the background. For instance, it is hard to find a memo on a which depends on attention, integrates the features that define the target. Attention is therefore thought to be desktop cluttered with paper. The task becomes much easier if the memo is a different color than all the other indispensable for successful conjunction search performance. pieces of paper on the desktop. Attention can also improve visual search. Even if the memo is not dis-I will present a different approach to understanding visual search and attention. This approach shows that tinguishable by color, it is easier to find if attention is drawn to its location. For instance, the telephone might a large body of the psychophysical and physiological visual search results can be explained without invoking ring and as I turn to answer it, I might discover the memo sitting next to the phone. In the course of this review, I a second limited-capacity attentive stage. In the scope of this review, visual attention plays a role when observ-will consider visual search and attention, in turn, and will present converging psychophysical and physiological ers are explicitly asked to attend to a location or feature, or when they are implicitly cued to a location or feature. evidence on the mechanisms that underlie these two phenomena. There is a growing body of literature that suggests that visual attention selects objects rather than locations, The task of finding a target among distractors is in general referred to as visual search. Typically there is a although the independence of attention to objects and to locations is still being debated (see Scholl, 2001 for single target that differs from the distractors along one or more dimensions. Let us start with the simple case a review). In some cases, attention has been shown to select objects as complex …