A comparison of the electrophysiological effects of formal and repetition priming

Three experiments investigated the electrophysiological consequences of repetition (e.g., scandal-scandal, buple-buple) and formal (e.g., scan-scandal, bup-buple) priming using words and nonwords. In each experiment, repetition and formal priming resulted in positive-going shifts in the event-related potential (ERP) that onset at approximately 200 ms poststimulus and were initially of similar magnitude. Subsequently, the repetition effect became larger than the formal priming effect. Although the word and nonword formal priming effects and the nonword repetition effects were greatest over midline and right hemisphere sites, the word repetition effects were greatest over the midline. It is suggested that the positive-going shift seen in the repetition and formal priming conditions was a modulation of the well-documented N400 component of the ERP. The topographic differences between the priming effects may have reflected differences in the nature of the representations to which cognitive operations are applied rather than differences in the nature of the operations themselves.