Distinct ERP signatures of word frequency, phrase frequency, and prototypicality in speech production

Recent studies have documented frequency effects for word n-grams, independently of word unigram frequency. Further studies have revealed constructional prototype effects, both at the word level as well as for phrases. The present speech production study investigates the time course of these effects for the production of prepositional phrases in English, using event related potentials (ERPs). For word frequency, oscillations in the theta range emerged. By contrast, phrase frequency showed a persistent effect over time. Furthermore, independent effects with different temporal and topographical signatures characterized phrasal prototypicality. In a simulation study we demonstrate that naive discrimination learning provides an alternative account of the data that is as least as powerful as a standard lexical predictor analysis. The implications of the current findings for models of language processing are discussed.