Event-related brain potentials support episodic-retrieval explanations of flanker negative priming

Brain-electrical correlates of identity-based negative priming (NP) were investigated, using event-related potentials (ERPs) and the lateralized readiness potential (LRP). Sixteen participants responded to the central digit ("target") of a triplet of digits while ignoring the identical flankers ("distractors"). In the DT condition designed to produce NP, the target was the preceding distractor. No stimuli were repeated in the control condition. In the TT condition supposed to produce positive priming (PP), the target stimulus was repeated. With this latter condition, design imbalances were avoided and ERP correlates of PP and NP could be compared. Significant behavioural PP (81-ms RT decrease in the TT condition) and NP effects (13-ms RT increase in the DT condition) were observed. Compared to control, left-posterior P300 amplitude was reduced for priming conditions TT and DT. It is argued that P300 findings are better in line with episodic-retrieval than activation/inhibition view since the latter predicts opposite ERP differences-to-control for TT and DT. P300 reduction may reflect an initial evaluation of both TT and DT probe displays as similar to the prime, resulting in a tendency to repeat the prime response. This tendency is correct in the TT condition but wrong in the DT condition, causing response conflict. A response-conflict account of flanker NP also receives support from the present LRP data: onset of the response-locked LRP occurred significantly earlier for DT than control, indicating increased motor processing time. Overall, data support episodic-retrieval explanations of flanker NP.