Bilingualism, Aging, and Cognitive Control

Research in cognitive aging has advanced enormously in the past few decades, producing detailed studies and sophisticated models of agerelated changes in cognitive functions (see chapters in Craik & Salthouse, 2000). Most of this research involves English-speaking participants, and conclusions have been drawn with little or no regard to the possibility that the participants might also speak another language. Yet the existing evidence strongly suggests that bilingualism has an effect on cognitive processing, at least for children and younger adults (see chapters in de Groot & Kroll, 1997, and Harris, 1992). What has not been examined is whether these effects persist over the life span and continue to influence changes in cognitive processing in bilingual older adults. One current reality is that bilingualism is increasingly common in many countries. As an example, the 1996 Canadian Census reported that approximately 11% of Canadians spoke English or French at home in addition to some other language; when only respondents more than age 65 were considered, the figure was 13% (Canada Census 1996, n.d.). In the United States, 17.9% of Americans reported that they spoke a language other than English at home, and it is a reasonable assumption that most of them also speak English (U.S. Census Bureau, 2003). Given the prevalence of bilingualism in North American society (and the prevalence is certainly greater in most European countries), it is important to establish the precise effects of bilingualism on cognitive processing and the way in which these effects are modulated by aging.