Is Semantic Processing Automatic?

McKenna, Erin
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University of Delaware
Emotion-induced blindness (EIB) occurs when an emotionally salient, irrelevant distractor grabs attention and causes impaired awareness for subsequent relevant targets. The extent of processing target pictures receive before emotional pictures block them from awareness remains unclear. The central interference theory proposes a two-stage model of processing that must occur for awareness of targets. During the first stage, stimuli are rapidly detected and semantically processed and if they contain target features, they are selected to enter stage 2. Stage 2 processing involves consolidation into working memory (Chun & Potter, 1995). The current study focused on whether missed target pictures were semantically processed before being blocked from awareness, as predicted by the central interference theory. We measured semantic processing using the N400 event-related potentials. We also examined whether or not targets were processed through early selection phases using the N2 component and whether or not they were consolidated into working memory using the P3b component. Participants viewed streams of pictures that could contain a negative (emotionally arousing picture), neutral (a nonthreatening picture of people or animals), or baseline (landscape) picture followed by a target picture that was related or unrelated to a previously presented object picture. We found that the N400 to an unrelated picture presented in the lag 2 position was similar across all distractor conditions. Behavioral data suggested that participants were impaired in detecting targets pictures presented at lag 2 when they were preceded by negative or neutral distractors. On the other hand, the ERP data hinted that participants were experiencing an emotional blink. The data support the central interference theory and suggest that semantic processing can occur without awareness.