The Role of Executive Control in Bilingual Lexical Access
thesisposted on 28.10.2014, 00:00 by Joanna C. Bovee
The purpose of the current study was to investigate the role of executive control components during bilingual lexical retrieval (i.e., word retrieval). Executive control components of interest included inhibition, updating of working memory, and shifting. The goals were to identify (a) which components play a role during lexical retrieval and (b) whether increased executive control ability is related to higher proficiency in a second language. To do this, I tested highly proficient English-Spanish bilinguals (BLs) and native English speakers who were current Spanish language learners (SLLs) on two switch tasks: one non-verbal (shape and color identification) and one verbal (picture-naming in English and Spanish). Additionally, participants completed a battery of tests that measured individual differences in executive control. More proficient bilinguals were predicted to exhibit greater executive control on the verbal switch task. In particular, they were expected to show more advanced use of the updating component than the less proficient bilinguals. Better executive control as measured by the individual differences battery was expected to be associated with more efficient processing during the verbal and nonverbal switch tasks. Results showed very few differences between participants groups. SLLs and BLs had similar switching and mixing costs on the non-verbal and verbal switching tasks. Both participant groups had similar working memory and shifting skills. The bilinguals did show enhanced inhibitory skills compared to SLL. Measures of executive control did not correlate well with the two switching tasks, and therefore were not predictive of performance on the switching tasks. These data suggest that being bilingual does not always afford enhanced executive control. Using two languages frequently could lead to enhanced control of language processing, but this does not necessarily extend to the non-verbal domain.