ABSTRACT
The purpose of this chapter is to assess the possible contributions of neuroscience data to testing the bilingual advantage in executive-functioning hypothesis. Citing one camp of cognitive neuroscientists, I agree that a focus on brain plasticity is not going to solve the debate on cognitive effects, especially not when brain changes are interpreted in the absence of behavioral differences. Supporting evidence for an advantage should involve showing that these differences are accompanied by unambiguous behavioral data substantiating a cognitive gain. Three different theories of the consequences of acquiring an L2 are reviewed and all three share the assumption that, in some sense, bilingual language control becomes more automatic as experience and proficiency is gained. Given that the effects of intensity, use, and timing of bilingualism on neural structures are nonlinear, it is unlikely that differences in structure can accurately predict differences in bilingual language control, much less, differences in far transfer to tasks measuring domain-general EF.
