Figure 8.13: Treisman’s theory of feature detection and integration During stage 1 of visual processing, in Treisman’s theory, the primitive features of all stimuli that reach the eyes are registered automatically and simultaneously—that is, in parallel. In this example, all the features of both the X and the V are registered simultaneously in the appropriate feature-mapping areas of the brain. Integration of features occurs at stage 2, during which information is processed serially, from one localized area of the visual field at a time. In this example, only the information from one stimulus, the X, is being processed. An instant later, stage 2 might operate on the V, but it cannot operate on the X and V at the same time.