From searching for features to searching for threat: Drawing the boundary between preattentive and attentive vision

The distinction between preattentive and attentional processing has been a key element in many theories of attention, but there are conflicting claims as to which functions are performed preattentively, and which require attention. Recent studies suggest that stimuli associated with strong emotions or threat are effective at capturing and/or holding attention. Especially relevant for the question of preattentive vision are search experiments showing that emotional stimuli are sometimes found more quickly than neutral stimuli. An examination of these experiments indicates that there is no evidence that the threatening nature of stimuli is detected preattentively. There is evidence, however, that participants can learn to associate particular features, combinations of features, or configurations of lines with threat, and use them to guide search to threat-related targets. This debate highlights the importance of determining not only what information is encoded preattentively, but how target features that are used to guide search are specified.