Does learning a second language enhance inhibitory processes and executive function?

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Most people easily modify their attention and behavior to meet the changing demands of their surroundings. For example, people easily shift from reading a book to answering a telephone call without confusing the content of the book with the content of the conversation. Similarly, people who are fluent in more than one language can effortlessly shift from one language to another. Moreover, when communicating with people who speak only one language, bilingual and multilingual speakers rarely experience intrusions from the other languages they speak, presumably because they are able to inhibit the language that is inappropriate for the situation. The inhibitory processes that allow bilingual or multilingual speakers to suppress a language may be the same processes that allow people to shift attention appropriately. If that is the case, inhibitory processes may be better developed in speakers of two or more languages and the possibility exists that general inhibitory processes might be strengthened in monolingual speakers as they learn and develop proficiency in a second language. Modifying behavior to meet the changing demands of the environment requires inhibiting habitual behaviors, shifting attention, and updating working memory. This crucially requires a process of inhibition, in order to keep salient but distracting information from gaining control of attention. An intriguing theory is that the inhibitory processes that allow humans to adapt to a changing environment are the same ones that allow bilinguals to suppress one language while speaking and to shift from one language to the other. The speculation is that inhibition is better developed in bilingual and multilingual speakers relative to speakers of only one language because bilinguals engage inhibitory control processes to control language output as well as to control attention. If correct, inhibitory processes may be strengthened in monolinguals as they learn and develop proficiency in a second language because they will engage this process to inhibit one language when words or phrases are expressed in their other language. To test this hypothesis, the investigator will directly measure event-related brain potentials (electrical potentials generated by populations of neurons milliseconds after a cognitive event) and behavioral responses in monolinguals who are developing second-language proficiency while they perform non-linguistic, auditory, and visual tasks of attention. The longitudinal design will allow an assessment of whether efficiency of inhibitory control increases as second-language learning progresses. In addition, the work will address the national under-representation of minorities in the sciences by funding and mentoring graduate and undergraduate students at a university with an extremely large minority student population.