The more you ignore me the closer I get: An ERP study of evaluative priming.

We used event-related brain potentials (ERPs) to investigate the various mental processes contributing to evaluative priming-that is, more positive judgments for targets preceded by affectively positive, as opposed to negative, prime stimuli. To ensure ecological validity, we employed a priori meaningful landscape pictures as targets and emotional adjectives as visual primes and presented both primes and targets for relatively long durations (>1 s). Prime-related lateralized readiness potentials (LRPs) revealed response priming as one source of the significant evaluative priming effect. On the other hand, greater right-frontal positive slow wave in the ERP for pictures following negative, as compared with positive, primes indicated altered impression formation, thus supporting automatic spreading activation and/or affect misattribution accounts. Moreover, target LRPs suggested conscious counter-control to reduce the evaluative priming net effect. Finally, when comparing prime ERPs for two groups of participants showing strong versus weak evaluative priming, we found strong evidence for the role of depth of prime processing: In the weak-effect group, prime words evoked an increased visual P1/N1 complex, a larger posterior P2 component, and a greater left-parietal processing negativity presumably reflecting semantic processing. By contrast, a larger medial-frontal P2/N2 complex in the strong-effect group suggested top-down inhibition of the prime's emotional content. Thus, trying to ignore the primes can actually increase, rather than decrease, the evaluative priming effect.