ERP signatures of cross-modal semantic fragment priming: early context effects in speech perception

Research in speech perception and language comprehension has shown that the processing and recognition of a word (the target) is facilitated if a related word (the prime) precedes it. This effect is observable even if the prime only consists of a word-initial fragment (e.g. bor- facilitates the recognition of border). The fragment priming paradigm has gained an important role in ERP studies on lexical access, since it reliably shows a distinct deflection at around 350 ms after word-onset, taken as index for lexical activation. While previous studies concentrated on form-related prime-target pairs, we are interested in ERP fragment priming components elicited by meaning-related pairs. For that purpose, we designed a cross-modal priming experiment, in which primes were either the initial syllables of their following targets (e.g. bor[der]-border; phonological condition) or the initial syllables of a semantic relative to these targets (e.g. mar[gin]-border; semantic condition). We found a reliable P350 effect in the phonological condition, but not in the semantic condition, and a N400 priming effect for the phonological condition. The phonological and the semantic condition differed from the control condition in an early negativity around 180 ms post onset. Our results are discussed with respect to ERP components that index form-based and meaning-based processing, possibly reflecting separate representations.