The bilingual effect on cognitive development: not an executive function advantage, but a differentiation of mental abilities

Abstract

Adopting a different theoretical framework from the one dominating the field, this study explored bilingualism influences on the development and differentiation of mental abilities. Albanian-Turkish bilingual (N = 122) and Albanian-speaking monolingual (N = 129) children, adolescents, and adults were assessed on monitoring, inhibitory control, processing efficiency, fluid reasoning, and vocabulary, and were asked to specify their own language efficiency (a cognizance index). Analyses showed a bilingual advantage in monitoring—adjusting for any fluid reasoning effects—which was larger in children. Moreover, a more pronounced bilingual benefit was observed for the incongruent condition RT of the attention task. Structural equation modelling showed though that the difference between language groups does not lie within the executive function domain (inhibitory control); it rather regards processing efficiency. Analyses also revealed increased differentiation of mental abilities in bilinguals, reflecting enhanced cognitive flexibility. Implications for cognitive developmental and individual differences theories are discussed.