Jason W. Gullifer, Ph. D. Psychology and Language Science - US grants

A hallmark of bilingual language processing is the parallel activation of the two languages during the use of only one language in production comprehension. In order to select a word in a single language from the myriad of co-activated words, bilinguals exploit an exquisite mechanism of language control that may come to affect cognitive and executive function. However, the exact nature of this mechanism is unknown. With National Science Foundation support, Mr. Jason Gullifer will collect data for his dissertation under the direction of Drs. Judith Kroll and Paola Dussias. Using an array of experimental methodologies, including behavioral and electrophysiological measures, Gullifer and colleagues will investigate whether differences in sentence structure between English and Spanish can function as a cue enabling bilingual speakers of those two languages to make a language choice during comprehension. Reaction times to name words in the context of sentences and brain potentials time-locked to the presentation of those words will be used to test the hypothesis that structural differences between languages can influence the degree of language co-activation. An independent behavioral experiment utilizing a method to measure cross-language syntactic priming will be used to determine the degree of representational overlap of each of the structures between Spanish and English, revealing the relationship between the degree of cross-language overlap and language co-activation.

The funded research has a number of broader impacts. Increasing diversity makes it important to learn a second language to enhance communication. The biological basis of second language learning was identified in 2005 in the AAAS publication 'Science' as one of the top 125 questions for scientific inquiry over the next quarter-century. The proposed research informs language learning by advancing models of language comprehension and production. Learning a second language also confers benefits to cognition, and the funded research will identify one mechanism by which language selection is achieved, helping to answer the question of how bilingualism impacts cognition. The proposed research includes a component for the mentorship of undergraduate research assistants by involving individuals who have been historically underrepresented in scientific research.

Project summary Bilinguals experience activation of both languages when they intend to use a one language. If multiple language alternatives are activated, how does a bilingual settle upon the intended alternative without interference from the unintended language? This problem is unique to bilinguals apart from monolinguals. Recent psycholinguistic and neuroscience approaches have argued for the existence of a cognitive control mechanism in the form of inhibition of the unintended language, and an emerging literature suggests that lifelong experience using cognitive control to mitigate language competition may generalize from the realm of language control to broader aspects of cognitive control. Yet, very little is known about precisely how language control comes to impact general cognitive function. Recent proposals implicate the role of language environment in how cognitive control is recruited for language selection. The proposed experiments investigate this potential locus of control by employing a longitudinal study of young adult bilinguals in Montreal before and after they switch the dominant language of their environment after secondary school. Montreal provides special test bed for the controlled study of bilingual populations. Children typically acquire French and English at an early age and attain high proficiency in both languages by secondary school, though they may be dominant in the use of either French or English. After secondary school some students enter programs in which the dominant language of the environment is switched from that of earlier development. The planned experiments exploit evidence from brain imaging, behavioral, and eye-tracking methodologies to assess the consequences of a switch in immersion context for brain structure, language selection, and executive function. Young adult speakers of French and English living in Montreal will undergo structural brain scans and be tested on a variety of cognitive and linguistic tasks at two time-points: (1) immediately after becoming immersed in the non-dominant at a post-secondary program and (2) one year following immersion. Control groups will consist of bilinguals who have not shifted their immersion context. Previous behavioral research shows that a shift in the dominant language of the immersion environment can have profound effects on lexical organization. However, the homogeneous bilingualism in Montreal allows for better control of variables that influence language processing and interactions (e.g., age of acquisition, country of origin, age of arrival, and proficiency level) isolating the variable of immersion context. Neuroimaging research shows that bilingual brains contain more grey-matter density in language and control regions (e.g., left inferior parietal lobe) compared to monolingual and that brain plasticity can be observed over relatively short time periods. Yet, no studies to our knowledge have explored structural reorganization longitudinally in bilingual speakers. Any effect of immersion context should generalize to bilinguals living elsewhere, but future research will be needed to confirm this and test how immersion might interact with other variables.