Decomposing unpleasantness: differential exogenous attention to disgusting and fearful stimuli.

Negative stimuli have consistently been shown to efficiently attract exogenous attention. Two different types of unpleasant stimuli, disgusting and fearful, sharing similar arousal and valence, are usually employed as a single category. However, since they diverge in several important aspects (biological functionality, associated feelings, and central and peripheral physiological correlates), it may be expected that their potential to capture attention differs. Event-related potentials and behavioral indices were recorded while participants were engaged in a digit categorization task in response to three types of irrelevant, distracting pictures: disgusting, fearful and neutral. Disgusting trials were associated with worse performance than fearful trials in the digit categorization task as revealed by reaction times and number of errors. Moreover, P2-associated cuneus activation and scalp anterior P2 amplitude were greater for disgusting than for fearful distracters. All these indices reveal that, under the experimental conditions employed in the present study, disgusting distracters are more efficient at attracting exogenous attention than are fearful distracters.