The neural bases of the bilingual advantage in cognitive control: An investigation of conflict adaptation phenomena.

Abstract

The present dissertation examines the effects of bilingualism on cognitive control, the ability to regulate attention, particularly in the face of multiple, competing sources of information. Across four experiments, I assess the conflict monitoring theory of the so-called "bilingual advantage", which states that bilinguals are better than monolinguals at detecting conflict between multiple sources of information and flexibly recruiting cognitive control to resolve such competition. In Experiment 1, I show that conflict adaptation, the phenomenon that individuals get better at resolving conflict immediately after encountering conflict, occurs across domains, a pre-requisite to determining whether bilingualism can improve conflict monitoring on non-linguistic tasks. Experiments 2 and 3 compare behavioral and neural conflict adaptation effects in bilinguals and monolinguals. I find that bilinguals are more accurate at detecting initial conflicts and show corresponding increases in activation in neural regions implicated in language-switching. Finally, Experiment 4 extends the bilingual advantage in conflict monitoring to syntactic ambiguity resolution and recognition memory.