Testing Theory II: A Close Look at the Methods and Logic Used in Evaluating a Theory of Visual Search and Attention
In chapter 10 we dealt with the topic of memory search and showed how reaction times have been used to infer search types. The logic developed for inferring different types of memory search on the basis of reaction time has been used more recently by Treisman and her colleagues for measuring types of visual search. The issue here is how we search our environment. Treisman and her colleagues have developed a theory of visual information processing that they term feature integration theory ( Treisman & Gelade, 1980; Treisman & Gormican, 1988; Treisman & Schmidt, 1982; Treisman & Souther, 1985). First, we outline the theory. Second, we consider experiments in visual search using the logic developed by Sternberg for inferring search types. Third, we examine additional predictions from feature integration theory examining the role of focal attention in visual information processing.
According to feature integration theory, early visual information processing occurs in two stages. In the first stage, environmental stimuli are analyzed at a feature level. That is, complex stimuli are broken down into component features. The initial stage of feature recording is thought to be preattentive, and features are held to be