ABSTRACT
This chapter provides a review of research prior to Elizabeth Peal and Wallace Lambert study and more recent studies on bilingualism and intelligence. It shows an effect within a sample of bilinguals and when two alternative models for the direction of causality were tested on the longitudinal data, the model claiming degree of bilingualism to be the causal link was more consistent with our obtained data than the model claiming cognitive ability to be the causal variable. Psychological studies of the relation between bilingualism and cognitive abilities began in the early 1920s out of concern raised by the flourishing of psychometric tests of intelligence. The methodological problems stemming from the reality of actual bilingual situations lend difficulty to supporting empirically the claim that bilingualism is associated with greater cognitive flexibility. In contrast to early psychological studies of childhood bilingualism, individual case studies by linguists had concluded that early bilingualism was advantageous to children's cognitive and linguistic development.
