The Role of Language Membership Information in Bilingual Language Control

• Main Author: Hoversten, Liv J
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01.01.2017
• Subjects: Cognitive psychology; Neurosciences; Psychology
• ISBN: 9780355461787; 0355461781

The human language system is remarkable in many respects, not least of which is the ability to accommodate more than one system of lexical and syntactic knowledge in the same individual. In fact, it is estimated that more than half of the world’s population is bilingual or multilingual. However, the cognitive processes that these individuals use to monitor and select the appropriate language for comprehension and production remain unclear. The goal of this dissertation was to asses different theories regarding bilinguals’ ability to control retrieval of linguistic information from long-term memory during language processing. Specifically, the studies described examined how and when bilinguals use language membership information during the activation and selection of lexical representations from each language for integration into sentence context. Chapter 1 describes an experiment that used the temporal precision of event-related potentials (ERPs) to answer two research questions: when language membership information is accessed relative to semantic access (i.e., conceptual retrieval) during word recognition and whether it can be used to modulate the degree of processing in the target and nontarget languages. Results demonstrated that language membership information becomes available prior to animacy information, which allows the bilingual brain to reduce the depth of processing in the nontarget language. A follow-up experiment described in Chapter 2 extended these results, also using the fine-grained temporal information offered by ERPs to establish the time course of influence of language membership information derived from sublexical sources in particular. Results confirmed that bilinguals are sensitive to orthographic regularities that distinguish between languages, even in the absence of lexical information. Furthermore, orthographic language membership information was available prior to lexical access, which may enable the restriction of lexical candidates to the target language early during word recognition. Finally, Chapter 3 describes an experiment designed to investigate the relative influences of semantic and language context on bilingual visual word recognition during reading. Eye movement data were used to determine the time course of activation of target and nontarget language meanings of interlingual homographs (IHs) when embedded in sentences. In a uniform monolingual language context, no influence of the nontarget language meaning of the IH was found early during lexical access. When the semantic context allowed for the integration of the nontarget but not the target language meaning, bilinguals seem to have accessed the nontarget meaning later during lexical access, only after integration of the target language meaning failed. These results suggest that language context may have allowed participants to ‘zoom in’ to the target language such that the nontarget language was less accessible under these conditions. Together, these experiments demonstrate the potential for partially selective lexical access. According to this perspective, the nontarget language is neither inaccessible nor fully active at all times. While the bilingual word recognition system is permeable to nontarget language representations, representations from target and nontarget languages are activated to different degrees according to their relevance to the global language context. In other words, the bilingual language control system is both flexible and dynamic in adjusting the gain of each language according to a particular context.