Authors:

BOZIC, M., Tyler, L.K., & MARSLEN-WILSON, W.D.

Reference:

Year of publication:

2008

CBU number:

7013

Abstract:

Lexical complexity plays a prominent role in modulating the activity of the fronto-temporal language network. Studies with regularly inflected words show that processing morpho-phonological complexity (e.g. stem + inflectional affix) activates left-lateralised areas, while lexical-semantic complexity (e.g. competition due to presence of embedded stems – e.g., clay/claim) engages bilateral frontal regions. The current efMRI experiment asked whether similar left-lateralised decomposition and bilateral competition processes hold for derivationally complex words, where the stem-affix relationship is strongly lexicalised and less semantically predictable. In a set of single spoken words we manipulated the presence of embedded stems and derivational suffixes with varying degrees of productivity, forming a gradient in the extent they are predicted to trigger competition and decomposition processes. Words were contrasted with a complex auditory baseline that does not trigger a speech percept (‘musical rain’, Uppenkamp et al, 2006). We found that stem competition generated by derivational complexity engages bilateral fronto-temporal language regions, but with no hemispheric dissociation comparable to that observed for inflections. This is arguably because derivational affixes do not trigger decompositional processes in the same way as inflectional affixes. We suggest a neuro-cognitive account of the representation and processing of derivationally complex forms in English.