Pre-stimulus alpha power as an index of proactive control of emotional distractors

The ability to focus on current goals without being distracted by goal-irrelevant information is highly adaptive. Emotional information captures our attention to a greater extent than neutral information; therefore ignoring emotional distractions may require a more effective control strategy. Using behavioural and EEG methods, we study the mechanisms used to control emotional distractions. In Experiment 1, participants performed a simple letter discrimination task at fixation, while irrelevant positive, negative and neutral images were presented peripherally. When distractors occurred on 25% of trials, emotional images were more distracting than neutral images. However, when distractors occurred on 75% of trials, both emotional and neutral distractors were effectively ignored, showing that we can control emotional distractions when they are expected. The attenuation of distraction in the high frequency condition may result from participants adopting a strategy of greater proactive control (i.e., anticipating and preparing to ignore distractors prior to onset) when distractors are expected. In Experiment 2, we are currently testing this hypothesis, recording EEG during task performance to measure pre-stimulus alpha suppression, an established index of anticipatory attention. Distractor valence (positive, negative, or neutral) is blocked, so that participants expect emotional or neutral distractors. If participants adopt proactive control in the high, but not low, distractor frequency condition, there should be greater pre-stimulus alpha suppression in the high frequency condition than in the low frequency condition. In addition, if ignoring emotional distractors requires greater proactive control, pre-stimulus alpha suppression should be greater during emotional distractor blocks than non-emotional distractor blocks.