Evidence Mounts Against the ‘Bilingual Advantage’
16th April 2018
A new meta-analysis published in Psychological Bulletin provides more reason for doubt. The authors averaged the results of 152 studies and found little evidence that bilingualism confers any general cognitive benefit. So what happened to all of the exciting “bilingual advantage” research that we hear so much about? When the authors of the meta-analysis compared effect sizes across the various studies, they found that the most imprecise studies — imprecise in the sense that their small sample sizes introduced a lot of random error — tended to report the most positive results. This is classic evidence of publication bias, whereby shaky studies are more likely to be published if they produce results that go in a favored direction. After correction for publication bias, the effects of bilingualism on cognitive inhibition, monitoring, shifting, and working memory were all effectively zero. Effects on attention and verbal fluency were actually negative, albeit small.