Bilinguals show poor insight into performance

Published: 29 February 2016 at 14:20


Monolingual speakers more likely to judge their own decisions more accurately

A new study indicates that people who speak two languages (bilinguals) are less accurate than monolinguals at judging their performance.

The research, published in the scientific journal Cognition, was a collaboration between the Multilanguage & Cognition (MULTAC) lab at Anglia Ruskin University and the Brain Decision Modelling (BDM) lab at the University of Cambridge.

The study, funded by the Leverhulme Trust and the Economic and Social Science Research Council (ESRC), investigated whether the daily use of two languages may improve decision-making.  In particular, it looked at how we rate the quality of our decisions, which is known as metacognitive processing.

Adult bilingual and monolingual speakers were required to make rapid decisions in a computer task.  Two circles were presented on the screen and each circle contained a variable number of dots.  Participants were asked to decide which one of the two circles contained more dots and rate how confident they were in their decision. 

Some trials were “easy”, in that the number of dots contained in one circle was clearly larger than the other.  However, other trials were more challenging, making it more difficult for participants to rate their level of confidence.

The study found that the bilingual participants were, on average, 10% less accurate than monolinguals in evaluating their own performance after each decision.  Monolingual speakers were therefore more aware of when they might have made a mistake and when they might have not. 

Given the increasing prevalence of bilingualism in the world, this line of research has practical implications in a range of business, political, safety and educational settings.

Dr Roberto Filippi, director of the Multilanguage & Cognition Lab (MULTAC) at Anglia Ruskin University, said:

“The results are somewhat against our initial predictions.  We often observe a bilingual advantage in attentional processing, and we thought that this advantage would extend to decision-making and metacognitive processing. 

“However, this does not seem to be the case.  We conducted the experiment twice, with two different groups of bilinguals and monolinguals, and obtained the same results. 

“Nobody has previously investigated the effect of second language acquisition on decision-making.  We are now conducting new research to understand why there is such a contrast between bilingual and monolingual speakers, and identify differences in brain structures.

“In our lab we have found scientific evidence for a bilingual advantage in attentional processes.  Now we found a possible bilingual disadvantage in metacognitive processing. 

“Our aim is to investigate the link between language and cognition in an unbiased and rigorous way.  A further study could involve evaluating the performance of bilingual and monolingual managers in a professional setting.”