Abstract: What is nature of morphological effects in lexical processing? Can they be reduced to lexical form effects, semantic effects, or the interaction between form and semantic processing? Are there explicit representations of morphological structures in the mental lexicon? These questions were investigated in two experiments on the Uyghur language, which is spoken in China’s Xinjiang area and is an agglutinate language with rich morphological structures. Experiment 1 used the visual-visual priming and cross-modal priming lexical decision tasks and manipulated the morphological relations between primes and targets. In both tasks, significant priming effects were observed for prime-target pairs that shared root morphemes and were semantically related as wholes, whether the targets were derived words (＋m＋o＋s / D， or free-root morphemes (＋m＋o＋s / R). [Here “m” denotes the morphological relation between primes and target, “o” orthographic relation, “s” semantic relation; and “+” denotes having the relation between primes and targets in the relevant dimension and “-“ having no relation.] Priming effects with similar magnitudes were also observed for words that were only semantically related (－m－o＋s / D). In contrast, no significant effect was observed for prime-target pairs that were morphologically related but not semantically related (＋m＋o－s / D) or that were only formally related (－m＋o－s / R). Experiment 2 took advantage of the fact that in Uyghur many words are borrowed from other languages and some of these words are morphologically related in the original languages but only semantically and formally related in Uyghur. Using the delayed repetition priming technique, this experiment compared the priming effects between Uyghur morphologically related words (＋m＋o＋s / D) , borrowed words (－m＋o＋s / D) and pure semantically related words (－m＋o＋s / D). The same pattern of priming effects were found for the three types of words in the short and long lag repetition conditions. These findings were interpreted as supporting the connectionist argument that morphological structure does not need to be represented explicitly in the lexicon and morphological effects in lexical processing can be seen as the result of interaction between semantic processing and form processing.

Key words: lexical processing, morphological priming, Uyghur, connectionist