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

Two lexical decision experiments were carried out in Spanish in order to address questions about the processing and representation of morphologically complex words in the mental lexicon. Responses to targets (e.g., mor-os "Moors") were found to be reliably slower and less accurate when they were preceded by stem homograph primes (mor-ir "to die") compared to unrelated control 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 stem as the stem homograph primes (moral "moral"). We take this as evidence that the stern homograph effect is a direct consequence of morphological decomposition in lexical access. In a second experiment, an inhibitory effect was observed when the same targets were preceded by primes that were not themselves stem homographic with the target, but rather allomorphically related to stems that were stem homographs (muer-e "she/he/it dies"). Since target 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.