Event related potentials reveal differences between morphological (prefixes) and phonological (syllables) processing...

Behavioral measures in visual priming tasks show opposite effects for syllables and morphemes, which indicate that they are processed by two independent systems. We used event related potentials (ERPs) to explore two priming situations in Spanish: prefix related words (reacción-REFORMA [reaction-reform]), in which prime and target words shared a first syllable that was also a prefix, and syllable related words (regalo-REFORMA [gift-reform.]), in which the shared first syllable was a pseudoprefix in the prime word. Prefix related pairs, unlike syllable related pairs, evoked a very early positivity in reaction to the target (at 150-250ms window), suggesting that the prefix information is immediately available, at a prelexical stage. By contrast, syllable related pairs showed a larger N400 effect. This late negativity may be caused by lateral inhibition among lexical candidates activated in the lexicon by the prime's first syllable.