Stem homograph inhibition and stem allomorphy: Representing and processinginflected forms in a multilevel lexical system

Two lexical decision experiments were carried out in Spanish in order to ad dress questions about the processing and representation of morphologically complex words in the mental lexicon. Responses to targets (e.g., mor-os "Mo ors") were found to be reliably slower and less accurate when they were pre ceded by stem homograph primes (mor-ir "to die") compared to unrelated cont rol primes (sill-a "chair"), and this inhibitory effect was over and above the marginal reaction time effect for morphologically unrelated primes that shared just as much left-to-right orthographic overlap with the target ste m as the stem homograph primes (moral "moral"). We take this as evidence th at the stern homograph effect is a direct consequence of morphological deco mposition in lexical access. In a second experiment, an inhibitory effect w as observed when the same targets were preceded by primes that were not the mselves stem homographic with the target, but rather allomorphically relate d to stems that were stem homographs (muer-e "she/he/it dies"). Since targe t inhibition was found for primes whose inflectional stems are not strictly ambiguous at the level of form, this pattern of results provides evidence for morphologically abstract (lemma-like) representations that are engaged in lexical access at a form-neutral level of morpholexical processing. (C) 1999 Academia Press.