Individual Differences in Context: A Neurolinguistic Investigation of Working Memory and L2 Development

This thesis examines the interplay between external and internal factors in second language acquisition by analyzing the role of individual differences in experiential (language contact) and cognitive (working memory) factors in linguistic development that takes place in traditional, at home classroom settings and during study abroad. The study aims to provide a multi-dimensional perspective on these relationships by assessing both behavioral and neural evidence. The study assesses changes in linguistic abilities (overall proficiency, grammaticality judgments, and oral production accuracy) and online processing (event-related potentials elicited during grammaticality judgment task) among intermediate-level learners of Spanish as a second language. Changes in proficiency and processing over the course of one semester of study are analyzed with regard to reported language contact hours and working memory abilities. Analyses revealed that learners in both the At Home and Study Abroad groups evidenced behavioral and processing changes from pre- to post-semester. Within the At Home group, language contact and working memory accounted for changes in (1) overall proficiency and (2) online processing of grammatical gender agreement on adjectives. Within the Study Abroad group, language contact accounted for (1) gains in judgment and production accuracy for grammatical gender agreement on adjectives and (2) changes in online processing of adjective agreement violations. Working memory did not account for behavioral or processing changes within the Study Abroad group. Results of this study contribute data to context-based and neurocognitive approaches to second language acquisition research. They also provide preliminary answers to Collentine and Freed’s (2004) call for theories of language acquisition and processing to take into consideration cognitive abilities and context of learning. Future research that utilizes a multidimensional approach informed by the fields of second language acquisition and cognitive neuroscience is likely to provide further insights into the relationships between external and internal factors in linguistic development and have significant implications for identifying the predictors of successful second language acquisition among adult learners.