In many studies comparing bilinguals to monolinguals, researchers have found that bilinguals outperform monolinguals on certain measures of cognitive control. This is called the bilingual advantage. The bilingual advantage most likely is caused by the bilingual's experience regularly switching between two languages and their respective grammatical properties. In order to appropriately switch between languages, the bilingual must a) control the selection of the target language according to the linguistic environment and b) resolve conflict between competing alternatives. If this hypothesis is true, then 1) the more language switching performed and language conflict resolved, the more cognitive advantage she will have, and 2) the more experience a bilingual has managing language switching and conflict, the more cognitive advantage she will have.
In order to investigate this claim, the researchers are recruiting college students in training programs that are either a) being trained to manage low levels of bilingual language switching and conflict such as learning a second language that is a signed language, which competes less with the native spoken language, or b) being trained to manage high levels of bilingual language switching and conflict, specifically simultaneous interpreting. Simultaneous interpreting is a complex cognitive task in which the bilingual must concurrently comprehend and produce two languages with differing grammatical properties. The participants are either beginning or advanced students (in both the low-switch/conflict and the high-switch/conflict groups) so that the role of experience will also be investigated. In addition, the researchers are recruiting both bimodal (signed language-spoken language) bilinguals and unimodal (spoken language-spoken language) bilinguals for each of the groups. A variety of language ability and cognitive ability measures are administered to the participants. The research will speak to differences and similarities between unimodal and bimodal bilinguals, and will investigate the role of cognitive enhancement based on amount of language switching and conflict resolution and experience managing the switching and conflict. It will also contribute to the training of a promising scholar.
The goal of the completed research was to examine the bilingual advantage. The bilingual advantage is the finding that bilinguals tend to outperform monolinguals on certain measures of cognitive control (such as the ability to be less distracted by irrelevant information and the ability to rapidly switch back and forth between tasks or sets of rules). The primary hypothesis for the source of the bilingual advantage is that resolving conflict (e.g., having two words come to mind for a single concept) and selecting the appropriate target language (i.e., not using one language when you mean to use the other) require cognitive control, and that bilinguals’ extensive use of cognitive control results in cognitive control enhancement. However, the bilingual advantage is somewhat controversial: some researchers find strong evidence for the advantage while others find no such evidence. We tested factors that might account for why some researchers find the advantage while others do not. We hypothesized that the language management demands for bilinguals might vary substantially, which would vary the amount of cognitive control needed to manage the demands. Specifically, we hypothesized that bilinguals in a college environment would be cued to use the dominant language by the environment (hearing lectures in the dominant language, hearing students between classes using the dominant language, hearing students in the dorms use the dominant language), such that excessive cognitive control would not be necessary—these bilinguals would automatically use the dominant language on a campus with little additional cognitive control needed. However, for bilinguals who are being trained to regularly process both languages simultaneously—comprehending one language while producing another language—the amount of cognitive control necessary to manage this task would be large and the cognitive control enhancements would be great. We therefore predicted that 1) advanced simultaneous interpreter students (e.g., individuals training to become U.N. interpreters) would outperform beginning simultaneous interpreter students because they would have more experience engaging in demanding cognitive control, and 2) advanced simultaneous interpreter students would outperform bilinguals without simultaneous interpreter training (e.g., typical bilingual college students). In order to test our hypotheses, we administered a variety of cognitive ability measures to a wide range of bilinguals differing in amount and type of bilingual training. In all, we tested 268 bilingual individuals from the Monterey Institute of International Studies (MIIS) and Princeton University. Previous research suggested that we should find differences between the groups such that bilinguals who presumably must recruit more cognitive control to manage both languages (e.g., interpreter students) should outperform bilinguals who presumably recruit less cognitive control to manage both languages (e.g., typical bilingual college students). However, the groups did not differ reliably on any of the measures of cognitive ability. Given that Princeton students might have higher cognitive abilities than the MIIS students in general, we compared groups within MIIS who should recruit more (interpreter students) or less (translation students) cognitive control and also compared groups within Princeton (fully bilingual vs. second language learners). There were no reliable differences. Also, given potential intelligence differences among the groups, which could mask other cognitive control differences, we statistically controlled for intelligence. There were no reliable differences. During these group analyses, occasional statistical differences between groups emerged, however, the pattern of results was not consistent and the results were generally uninterpretable. To conclude, we hypothesized that bilinguals with greater cognitive control demands to manage their two languages would demonstrate greater cognitive control relative to bilinguals with lesser cognitive demands to manage their two languages. Our hypothesis was not supported by the data. While the results did not confirm our hypothesis, the work has intellectual merit and broader impacts. This study advances knowledge by examining a potential source of the bilingual advantage and ruling it out as a viable factor for future research. This work also offers a baseline of cognitive ability scores within these groups for future researchers and interpreter training programs. The current study represents the largest investigation of cognitive abilities and specially trained bilinguals to date and was conducted by qualified researchers with the resources to carry out the study appropriately. The study examined a novel potential source of the bilingual advantage, which would have been transformative had we found evidence for our hypothesis: the results could have helped parents make language decisions for their children, educators make language curriculum decisions for their students, and young adults make career choices for themselves. As it stands, we know that other factors need to be investigated to understand the bilingual advantage. The research in this area has impacted how many inside and outside of academia view bilingualism. For example, parents were previously discouraged from raising their children bilingually and are now encouraged, in large part due to the bilingual advantage research. Future research is necessary to determine the reliability of the bilingual advantage and its source.
