The Relationship Between Executive Function and Bilingual Language Control

© 2019 Gabriel Hans OngMany contemporary proposals of bilingualism conjecture that domain-general Executive Functions (EFs) are fundamental to language control. These proposals revolve around two main observations: the first is that bilinguals have been shown to demonstrate superior performance on tasks used to measure non-linguistic EFs, and the second is that language switching superficially appears to relate to switching between tasks (a process which has been associated with EFs) in that they both induce a Response Time (RT) cost. Critically, direct evidence for the involvement of EFs in both non-linguistic and linguistic bilingual processing have not been demonstrated, but merely speculated. In this thesis, I present a series of four analyses, where I explicitly investigate the presence of EFs in bilingual processing by expressing their impact as a set of cognitive model parameter changes to task performance. The results reveal that bilingual behaviour across both the non-linguistic and linguistic domains do not exhibit signs of EFs, but instead demonstrate the influence of other lower-level general cognitive processes. The main conclusions of this thesis are as follows: A) the putative bilingual advantage is attributed to enhanced selective attention and B) language switches are attributed to automatic bindings between language information and response. These findings are discussed in terms of their implications for current frameworks of language control and bilingualism in general