Cognitive Benefits of Bilingualism

In stark contrast to early suspicions that bilingual children were at risk of retardation or at best, “mentally confused” (Bialystok, 2005), recent research links bilingualism to cognitive reserve and suggests it may offer protection against dementia in old age. Cognitive reserve describes a kind of resilience which appears to mediate the relationship between brain pathology and the clinical expression of that pathology; it is thought that this resilience derives from more efficient use of brain networks and/or the ability to deploy differential brain networks to a given task (Stern, 2002). Using a sample drawn from a memory clinic, Bialystok, Craik and Freedman (2007) found that bilingual patients presented symptoms of dementia three to four years later than monolingual patients. A second study, featuring a different sample, found that the first clinical appointments of bilinguals occurred 4.3 years later and the estimated age of onset (based on self or relative reports) was 5.1 years later than monolinguals. Although these results should be viewed with some caution due to social and cultural differences between participants, the difference is dramatic and has understandably caused much excitement about the potential impact of bilingualism on the efficiency and resilience of the brain.

The suggestion that bilingualism could enhance general cognitive performance is not new. Following the first reports of positive cognitive effects in Peal and Lambert’s (1962) landmark study, bilingualism has been linked to numerous cognitive benefits including improved metalinguistic awareness (Ben-Zeev, 1977; Ianco-Worrall, 1972), creativity (Kessler & Quinn, 1987; Ricciardelli, 1992) and problem-solving (Kessler & Quinn, 1980). In recent years, an influential area of research has explored the relationship between bilingualism and executive control, that is, the ability to selectively attend to stimuli and to inhibit inappropriate responses in order to achieve desired goals. A large number of studies (reviewed below) have found that bilinguals outperform their monolingual peers in tests involving cognitive conflict. Most of this research has focused on individuals who were bilingual from birth or early childhood, but a recent study found similar advantages in late-proficiency Chinese-English bilinguals who acquired their second language between the ages of 12 and 19 years old (Tao, Marzecova, Taft, Asanowicz, & Wodniecka, 2011). It is widely hypothesized that the bilingual advantage in these tasks arises because the bilingual brain places additional demands on a domain-general aspect of executive control in order to selectively attend to two competing language systems (e.g. Bialystok, Craik, Green & Gollan, 2009; Costa, Hernandez, Costa-Faidella, & Sebastian-Galles, 2009; Hinchley & Klein, 2011).

It protects against the onset of dementia in old age and produces numerous sensory and executive cognitive benefits in life.