Cognitive control in linguistic and non-linguistic contexts in bilinguals and monolingual

Open Access
Author:
Ting, Caitlin Yeh-Shan
Graduate Program:
Psychology
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
November 21, 2013
Committee Members:
  • Adriana Van Hell, Thesis Advisor
Keywords:
  • bilingualism
  • cognitive control
  • homograph processing
  • lexical ambiguity
  • psycholinguistics
  • word recognition
Abstract:
Research on bilingual language processing shows that bilinguals always have their two languages active, even in situations that require the use of only one language. So how do bilinguals successfully perform in one language without the other language intruding, and how do bilinguals seamlessly switch between their two languages when required? What control mechanism can explain how a bilingual manages to select what language they are speaking in? Is this mechanism specific to the practiced domain of language or does it also extend to more general, non-linguistic tasks requiring cognitive control? The present study examines the cognitive correlates employed by bilinguals and monolinguals in both linguistic and non-linguistic contexts, and provides further insight into psycholinguistic models, such as the Inhibitory Control model (Green, 1998). Given that bilinguals have a unique experience with cognitive control as a result of managing the pervasive parallel activation of their two languages, I investigate whether bilinguals and monolinguals recruit the same cognitive mechanisms in linguistic and non-linguistic contexts. Cognitive control in linguistic and non-linguistic contexts is examined in English-Spanish bilinguals, Spanish-English bilinguals, and English monolinguals. Bilinguals and monolinguals are presented with interlingual and intralingual homographs and controls in a language-specific (English) lexical decision task and in a generalized lexical decision task (linguistic context) and complete a non-verbal task switching task (non-linguistic context). In the English lexical decision task, bilinguals tested in their first language recognized interlingual homographs more quickly than matched controls, whereas bilinguals tested in their second language did not recognize interlingual homographs differently than the matched controls. Meanwhile, both groups of bilinguals and the monolinguals recognized intralingual homographs more quickly than matched the controls. In the generalized lexical decision task, only the Spanish-English bilinguals recognized interlingual homographs differently than the matched controls. In particular, Spanish-English bilinguals recognized these homographs more quickly than the controls. Moreover, both bilingual groups recognized intralingual homographs more quickly than the matched controls. In the cued color-shape task, bilinguals and monolinguals experienced a switch cost, where participants were slower and less accurate to respond to switch trials as compared to non-switch trials. The magnitude of the switch cost was not different for bilinguals and monolinguals. Response latency data from the lexical decision tasks suggest that lexical ambiguity within and across languages does not require suppression of one lexical candidate. Instead, it appears that a speaker is able to respond as soon as a homograph’s representations are recognized and before an alternate lexical candidate is considered, eliminating semantic competition from occurring. Moreover, this study complements recent behavioral studies that have begun to examine how the role of executive control in linguistic tasks relates to bilingual performance in non-linguistic tasks by investigating differences between bilinguals and monolinguals in their use of executive control in linguistic and non-linguistic contexts. In particular, the findings from this study suggest that bilinguals do not differ from monolinguals in how they employ cognitive control in linguistic contexts. Moreover, it appears that bilinguals’ practice with executive control in linguistic tasks does not extend to their performance on non-linguistic tasks, because both bilinguals and monolinguals experience switch costs, where they respond less quickly and less accurate to switch trials as compared to non-switch trials, and the magnitude of these switch costs were not different.