The Brain Mechanisms Underlying the Cognitive Benefits of Bilingualism may be Extraordinarily Difficult to Discover

The hypothesis that coordinating two or more languages leads to an enhancement in executive functioning has been intensely studied for the past decade with very mixed results. The purpose of this review and analysis is to consider why it has been (and will continue to be) difficult to discover the brain mechanisms underlying any cognitive benefits to bilingualism. Six reasons are discussed: 1) the phenomenon may not actually exist; 2) the cognitive neuroscientists investigating bilingual advantages may have been studying the wrong component of executive functioning; 3) most experiments use risky small numbers of participants and are underpowered; 4) the neural differences between groups do not align with the behavioral differences; 5) neural differences sometimes suffer from valence ambiguity, that is, disagreements whether “more” implies better or worse functioning and 6) neural differences often suffer from kind ambiguity, that is, disagreements regarding what type of mental events the pattern of activation in a region-of-interest actually reflects

Beyond Panglossian Optimism: Larger N2 Amplitudes Probably Signal a Bilingual Disadvantage in Conflict Monitoring

In this special issue on the brain mechanisms that lead to cognitive benefits of bilingualism we discussed six reasons why it will be very difficult to discover those mechanisms. Many of these problems apply to the article by Fernandez, Acosta, Douglass, Doshi, and Tartar that also appears in the special issue. These concerns include the following: 1) an overly optimistic assessment of the replicability of bilingual advantages in behavioral studies, 2) reliance on risky small samples sizes, 3) failures to match the samples on demographic characteristics such as immigrant status, and 4) language group differences that occur in neural measures (i.e., N2 amplitude), but not in the behavioral data. Furthermore the N2 amplitude measure in general suffers from valence ambiguity: larger N2 amplitudes reported for bilinguals are more likely to reflect poorer conflict resolution rather than enhanced inhibitory control