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Department of Cognitive Science

Seminar Abstract

Morphological priming in speech production: There's butter in butterfly but no corn in corner.

Speaker : Professor Niels Schiller, Leiden Institute for Brain and Cognition and Leiden University Center for Linguistics, Leiden University, The Netherlands.
Date : 11th of December 2012, 4:00PM until 5:30PM
Location : C5C498 - Palermo Room, Macquarie University.

This talk will be about how we plan and produce speech. More specifically, how do we put together words and sentences and what are the linguistic units that need to be activated and retrieved from long-term memory. For instance, words can consist of smaller meaningful elements called “morphemes”, e.g. the Dutch compound vaatwasser (‘dishwasher’) consisting of vaat (‘dirty dishes’) and wasser (derived from wassen ‘to wash, to clean’). How do we represent words like vaatwasser in our memory – as one holistic entity or do we also store the elements vaat and wasser separately? The present study investigated morphological priming in Dutch as well as its time course and neural correlates in overt speech production using a long-lag priming paradigm. Prime words were compounds (e.g. the word jaszak, ‘coat pocket’) that were morphologically related to a picture name (e.g. jas ‘coat’) or form-related monomorphemic words (e.g. jasmijn, ‘jasmine’ for jas). The morphologically related prime compounds could be semantically transparent (e.g. eksternest, ‘magpie nest’) or opaque (e.g. eksteroog, lit. ‘magpie eye’, but meaning ‘corn’ on a toe, for a picture of a magpie, Dutch ekster). Behavioral (reaction time), event-related potential (ERP) and functional neuroimaging (fMRI) data were collected in separate sessions. The production of morphologically related and complex words facilitated subsequent picture naming and elicited a reduced N400 compared with unrelated prime words. The effects did not differ for transparent and opaque relations. Mere form overlap between a prime word and a target picture name did not affect picture naming. These results suggest that morphological priming in language production cannot be reduced to semantic and/or phonological processing. Moreover, morphologically related but not form-related words led to a neural priming effect in the left inferior frontal gyrus (LIFG). The time course of these priming effects as reflected in the ERP measure is in accordance with a meta-analytic temporal estimate of morphological encoding in speaking. The neuroimaging results point to a functional role of the LIFG in morphological information processing during language production contrary to previous meta-analytic findings, since the effects seem to be independent of semantic overlap. It is suggested that the LIFG subserves word form encoding in language production.