Thesis defense Vitória Piai (Donders Series 144)
3 March 2014
Promotors: Prof.dr. H. Schriefers, Prof. dr. A. Roelofs
Choosing our words: Lexical competition and the involvement of attention in spoken word production
A core process in spoken language production is the quick and accurate retrieval of intended words from long-term memory. According to a prominent theory, conceptually driven word retrieval involves the activation of a set of candidate words in left middle temporal cortex, and competitive selection of the intended word from this set regulated by frontal cortical mechanisms. However, although competition is widely regarded in the cognitive neurosciences as a ubiquitous mechanism, its role in lexical selection has recently been disputed.
This dissertation presents a series of studies examining some recent challenges to the hypothesis that co-activated words compete for selection and, therefore, influence how long it takes to select a target word. Using behavioural methods, as well as neuroimaging techniques (electro- and magnetoencephalography and functional magnetic resonance imaging), I critically evaluated the alternative accounts. The results, presented in six experimental chapters, led me to argue that alternative hypotheses lack theoretical specification and, more importantly, empirical support to replace the competition hypothesis. Therefore, I conclude that the lexical competition hypothesis (still) provides the best explanatory framework for understanding lexical selection in spoken word production.