Relevance of the Irrelevant : Using Task-Irrelevant Emotional Stimuli to Test the Load-Hypothesis through ERP’s

Abstract: The role of attention and perceptual resources were studied in a one-back task and a letter-search task, both using the same stimuli. In the letter task, pictures were used as task-irrelevant and distracting emotional stimuli. The emotional processing of the pictures was measured through the Late Positive Potential (LPP), an event-related potential (ERP) recorded with EEG. LPP activity was significantly greater to emotional than neutral stimuli during the one-back task; this shows that emotional stimuli were processed during an easy task (low load). However, LPP activity dropped for all stimuli during the difficult perceptual task (high load). Selective processes of attention are discussed, in relation to Load Theory and the ability to ignore task-irrelevant, but emotionally significant, stimuli.