Focal-attentive and preattentive processes in letter- and figure-search tasks.

Evidence for preattentive and focal-attentive processes was obtained with two reaction-time tasks. In each case, effects of preattentive processes were identified by stimulating different proportions of the visual field. By varying the length of the search path, the effects of focal-attentive processes were identified. The first task, which required scanning arrays of letters, yielded short reaction times whereas the second task, which required the location of figures, led to long reaction times. The difference is explained by low automation and the strong demands of the latter task. The data do not indicate an interaction between preattentive and focal-attentive processes.