ERP effects of short interval masked associative and repetition priming

In a previous study we used event-related potentials to dissociate semantic (associative) and repetition priming when prime words were masked below (40 ms primes) and above (80 and 120 ms primes) levels of awareness (Holcomb, P. J., Reder, L., Misra, M., & Grainger, J. (2005). Masked priming: an event-related brain potential study of repetition and semantic effects. Cognitive Brain Research, 24, 155--172.). While robust priming effects were present on the N400 component regardless of the prime duration in the repetition priming experiment, in the semantic priming experiment significant priming effects were only obtained when primes were consciously detected. In the current study we again compared associative and repetition priming, but this time within a single experiment and using a short interval priming paradigm. As in several recent studies we again found robust repetition priming effects on both the N400 and an earlier index of priming, the N250. However, there was no evidence of any priming effect in the semantic/associative condition. The findings are discussed in the context of the functional significance of masked priming effects.