PHONOLOGICAL EFFECTS ON THE AUDITORY N400 EVENT-RELATED BRAIN POTENTIAL

We report 3 experiments exploring the responsiveness of the auditory N 400 event-related potential to the phonological relations between word or non-word targets and preceding prime words. When subjects had to d ecide whether primes and targets rhymed, non-rhyming words produced gr eater negativity in the N400 time range than rhyming words. The same e ffect was obtained when these targets were spoken by another voice tha n the prime words, suggesting that the effect is determined by phonolo gical factors, and not merely by a physical-acoustic mismatch (Experim ent 1). In the rhyming task, the differential N400 for non-rhyming vs. rhyming words was equally pronounced for non-rhyming vs. rhyming non- words (Experiment 2). In a lexical decision task on the same stimuli, a difference between non-rhyming and rhyming targets was obtained for words, but not for non-words (Experiment 3). The results show that the auditory N400 is sensitive to phonological variables. It is further p roposed that phonological effects on the auditory N400 are not manifes tations unique to phonological processes that demand conscious attenti on, but may also reflect operations that are performed automatically d uring auditory word recognition.