A new study done by Minna Lehtonen and her research group at the Department of Psychology at Åbo Akademi University shows that bilingualism does not seem to increase the cognitive skills related to executive functions in adult bilinguals.
According to Lehtonen, “Active use of two languages and switching between languages has been believed to train these functions, but our comprehensive overview of the entire existing research does not support this statement”.
Their study consisted of a meta-analysis of a total of 152 studies focusing on bilingual and monolingual adults. The participants were judged on their performance in tasks that measured different areas of executive functions.
Studies like this one had also been preformed in 27 other countries where bilingualism takes many forms. In all of these studies according to Lehtonen and her team, no significant benefits were found for bilinguals in sub-areas of executive functions.
Factors that were specifically looked at included age of acquisition of the second language, the age of participant, and the language pair. According to Lehtonen, the results indicate that bilingualism or active use of another language does not improve executive functions in healthy adults.
https://www.sciencedaily.com/releases/2018/03/180305093035.htm