This dissertation project tests whether adults who are bilingual (who learned two languages as children) are better at learning a foreign language than are monolingual adults. Previous research suggests that bilinguals have an advantage over monolinguals at some tasks, including creative thinking and problem solving. Recently, researchers have also claimed that bilinguals are better than monolinguals at learning another language, but this hypothesis has not yet been tested systematically.
This project will examine this hypothesized advantage by having bilingual adults learn a language that they don't already know--one that is, in fact, an artificial language, which by design they could not already have been exposed to--and comparing their performance to that of monolingual adults under the same learning conditions. The proficiency that participants attain in the language, as well as measures of their brain activity while they process the language, will be tested at two points, once early on during learning (at low proficiency) and once at the end of training (at high proficiency). The project will also evaluate the effect of the context in which the artificial language is acquired by comparing learning in a classroom to learning in an immersion context. Half of the bilingual participants will train under classroom-like conditions; whereas the second half of this group will receive training under immersion-like conditions. The corresponding data for the monolingual group, which has already been collected, indicates that by the time monolingual learners reach high proficiency, their brain patterns look similar to those of native speakers of most languages, particularly for those who underwent immersion-like training. This suggests that monolingual foreign language learners can indeed become like native speakers in how their brains learn and process the language. The data from bilinguals will be collected and compared to the data from monolinguals. The hypothesized bilingual advantage in acquiring new languages predicts that the bilingual participants will be faster and more accurate than the monolinguals in learning the artificial language. It also predicts that their brain patterns will be even more similar to patterns that are typically found when native speakers process sentences in their own first language.
Because learning foreign languages makes an important contribution to the lives of many people the world over in today's global economy, and because proficiency in foreign languages is also critical to the security needs of the government, findings from this project may have broader consequences for education, policy and security.
Are bilinguals better than monolinguals at learning an additional language? Popular belief holds that bilinguals have an advantage over monolinguals at foreign language learning, but little scientific research has investigated this claim. Moreover, no previous studies have compared the brain patterns of bilingual and monolingual learners of a foreign language, to test whether they may differ and how. This study aimed to empirically test the hypothesis that bilinguals are better than monolinguals at language learning, and to examine whether their brain patterns differ during language learning. Knowing whether such differences exist and what factors (such as type of learning environment, e.g., classroom or immersion) may constrain or enhance learning in each group, has theoretical and practical importance, especially for foreign language education and bilingual language maintenance programs. This study compared additional language learning in English monolingual and Chinese-English bilingual adults. All participants were trained on a small romance language-like artificial language called Brocanto2. Participants in each group (monolingual and bilingual) were trained in either a traditional foreign language classroom-like context (they heard examples of words and sentences, and were given instruction on grammar rules) or a more naturalistic, immersion-like context (with word and sentence examples, but no grammar rule instruction). At two points in the study, low and high experience, we measured participantsâ€™ ability to discriminate between good (grammatical) and bad (ungrammatical) sentences in the language. We also recorded their electrophysiological brain activity in response to these sentences, using the widely-employed technique of Event-Related Potentials, or ERPs. In the instructed, classroom-like condition, bilinguals and monolinguals were similar in their ability to speak and understand Brocanto2 as well as their ability to discriminate between good and bad sentences. However, the bilinguals showed a stronger native language-like ERP response than the monolinguals. This suggests that even in the absence of an observed bilingual advantage in performance, bilinguals may still show more native-like brain processing than monolinguals. However, a different pattern of results emerged in the uninstructed, immersion-like condition. In this condition, like the instructed condition, bilinguals and monolinguals could speak and understand Brocanto2 with similar ability, though the monolinguals were better at discriminating between good and bad sentences. Crucially however, the monolinguals showed more native language-like brain responses than the bilinguals. In this condition, then, there was neither a performance advantage nor a neurocognitive advantage observed for the bilinguals; rather the monolinguals showed more native language-like brain patterns. Overall, the outcomes from this project indicate that, despite popular belief, bilingual advantages at language learning are not absolute and that differences between bilinguals and monolinguals in performance and neurocognitive measures are related the context of learning.