Does bilingualism make you smarter? An investigation of language and cognitive control.

Speaking two languages proficiently from childhood (balanced bilingualism) may benefit cognition. On tasks requiring cognitive control (CC)—the ability to override conflict from extraneous information—bilinguals often outperform monolinguals. This may be due to bilinguals’ frequent suppression of one language over another, acting as naturalistic “cognitive-control training.” The scope of the “bilingual advantage” is poorly understood. We investigated if bilinguals’ benefit includes the ability to revise misinterpretations during language processing, motivated by research showing that, in monolinguals, CC recruits the same cortical regions as correcting language comprehension errors. We also tested if briefly practicing a memory task with high conflict-resolution demands (short-term CC training) improves reinterpretation. Spanish-Catalan bilinguals and Spanish monolinguals read easy sentences and sentences susceptible to misinterpretation, before and after completing either a high- or low-conflict “3-back” memory task. While reading, subjects answered questions testing for misanalysis. The memory task presented words sequentially and subjects indicated when one appeared 3 items previously. Only the high-conflict version contained “lure” words presented 2, 4, or 5 items before, interfering with the correct 3-back item. Bilinguals outperformed monolinguals in the high-conflict, but not low-conflict, version; they also exhibited better reading comprehension across all sentences. Irrespective of group, subjects’ improvement on “lure” trials during the experiment predicted pretest-to-posttest comprehension improvement on sentences requiring revision. For some, briefly practicing conflict-resolution increases CC, benefiting subsequent sentence-reinterpretation skills. Thus, bilingualism may bestow an advantage when conflict-detection is crucial, including during language processing involving occasional reinterpretation demands. Critically, CC training in monolinguals may yield similar benefits.