Harald Clahsen, University of Essex

Dual-mechanism morphology refers to a family of psycholinguistic models which hold that morphologically complex word forms can be processed both associatively, i.e. through stored full-form representations and by rules that decompose or parse inflected or derived word forms into morphological constituents. We present a brief overview of some relevant experimental results on English and other languages and of different variants of dual-mechanism models that are currently discussed in the literature. Finally, we briefly outline how dual-mechanism morphology can be implemented into morphological theory. Our understanding of how an adult native speaker/hearer processes inflected word forms in real time has increased considerably over the last decade. Experimental studies using a range of different psycholinguistic methods and techniques, e.g. lexical decision, priming, event-related potentials (ERPs), have led to a number of consistent and replicable results, e.g. frequency effects for inflected word forms in lexical decision tasks, priming effects for inflected word forms in different kinds of priming experiments, and left-anterior negativities for incorrectly inflected word forms in ERP violation studies; see Clahsen (1999) and Pinker (1999), for review. The theoretical interpretation of these and other results on morphological processing in adult native speakers is controversial; basically, three different approaches can be distinguished. On one side are different kinds of associative single-mechanism models claiming that all inflected words are stored and processed within a single associative system using distributed representations (see e.g. Bybee 1995, Sereno & Jongman 1997, among others). The morphological structure of an inflected word is not explicitly represented in these models; instead, these models implement networks that represent the mapping relationship between different word forms through associatively linked orthographic, phonological and semantic codes. A radical