Feature integration that routinely occurs without focal attention.

To analyze visual scenes, the visual system decomposes the visual scene into features that are processed in parallel by separate subsystems. Certain theories (Treisman, Wolfe) propose that these subsystems function independently before focal attention integrates their output. We describe a new paradigm-the gestalt detection task--that directly assesses the degree of preattentive dependence between any two subsystems. We present five experiments that test whether the subsystems that process form and color function independently in processing brief (and, therefore, preattentively processed) stimuli. Our data show that these two subsystems interact during the preattentive processing of feature-dependent information. They are synergistic when the information they receive is consistent; they are antagonistic when the information they receive is inconsistent.