Can we shield ourselves from task disturbance by emotion-laden stimulation?

Emotion-laden stimuli can disturb information processing in an unrelated cognitive task. We investigated the possibilities and limitations for shielding from such disturbance. Participants performed a simple categorization task while being simultaneously exposed to negative, neutral, and positive pictures. Performance dropped with negative pictures, relative to positive and neutral stimuli. Unlike Stroop or Simon interference effects, this negativity-based disturbance did not reduce as a function of previous experience of disturbance (Exp. 1) or of announcement of such disturbance on a trial-by-trial basis (Exps. 2 and 3). We found hints of a reduction of negativity-based disturbance, however, when negative stimulation occurred with high list-wide probability (Exp. 4). These observations suggest that the control of negativity-based task disturbance might be possible in a sustained manner, but that it is severely limited when operating in a transient, moment-to-moment manner.