Cognitive Advantages in Adult Turkish Bilingual Immigrants - a Question of the Chicken or the Egg.

A number of studies suggest both cognitive disadvantages and advantages of bilingualism. In the current study, it is attempted to provide an account of the cognitive advantages associated with bilingualism in a Turkish immigrant population in Denmark.The total sample consisted of 71 middle-aged and older adults born and raised in Turkey who had migrated to Denmark in their teenage years or later. All participants were assessed with a neuropsychological test battery and degree of Turkish-Danish bilingualism was estimated via rater assessment according to a three-point scale. Associations between bilingualism and cognitive function were established for five cognitive domains: executive function, memory, language, visuospatial function and speed. Analysis of covariance was used to estimate the independent association between bilingualism and cognitive function for each cognitive domain. Covariates included education, gender, ethnicity, and proportion of life lived in Denmark. In unadjusted analyses, greater degree of bilingualism was associated with better executive functioning (p < .001), visuospatial functioning (p = .002) and speed (p < .001). However, in analyses adjusted for covariates only executive functioning (p = .01) and task switching ability (p = .01) remained significant, while a trend for better memory function was found in those with a high degree of bilingualism (p = .07).The current study indicates that bilingual Turkish immigrants have better executive functioning and episodic memory compared to Turkish immigrant monolinguals. Whether this is due to the effects of bilingualism or reflects inherent cognitive abilities in those able to acquire bilingualism in later life remains to be resolved.