The Cognitive Tests and their Results
The researchers involved gave the participants a series of cognitive tests that evaluated their verbal reasoning, their vocabulary, verbal fluency, ability to process information and their reading abilities. Bilingual participants scored generally much better than monolingual ones, even when the original intelligence tests did not reflect such an advantage over the rest. The difference was particularly noticeable in the areas of reading and general intelligence. The results also showed that performance improved the more languages the participants spoke, as the results of those who could speak three or four languages were even better than the results of the bilinguals.
A total of 262 of the 853 participants could speak more than one language, 65 of which reported to have learnt the language after the age of 18. According to Fergus Craik, scientist at the Rotman Research Institute, the study serves as excellent evidence to support the relationship between language and cognitive development, while Bak argues that the results show that the benefits of learning a language still persist even if the language is learnt later in life and even when perfect fluency is not achieved.
The group of participants was made up of Scottish citizens of around 70 years of age. The cohort had already been tested back in 1947 and was found to be a very homogeneous group of English native speakers who were all born and raised near Edinburgh. The homogeneity helped rule out other factors that could be influencing the results, like ethnicity or immigration status.