Graduation Year

2019

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Psychology

Major Professor

Chad Dubé, Ph.D.

Co-Major Professor

Elizabeth Schotter, Ph.D.

Committee Member

Judith Bryant, Ph.D.

Committee Member

Kyna Betancourt, Ph.D.

Committee Member

Geoff Potts, Ph.D.

Keywords

bilingualism, cognition, executive functioning, inhibition, psycholinguistics

Abstract

Bilingual language control refers to how bilinguals are able to speak exclusively in one language without the unintended language intruding. Two prominent verbal theories of bilingual language control have been proposed by researchers: the inhibitory control model (ICM) and the lexical selection mechanism model (LSM). The ICM posits that domain-general inhibition is employed in order to suppress the unintended language’s activation. The LSM posits that inhibition is not used; rather a lexical selection mechanism targets only the intended language’s words. In order to better test the theories’ hypotheses, I developed computational models to estimate participants’ reaction times when naming in blocks of semantically related pictures and in blocks of semantically unrelated pictures. For these tasks, the ICM model predicts that semantic interference will be abolished when bilinguals switch languages, while the LSM model does not. In Experiment One, English-Spanish bilinguals named pictures that were either semantically related to the previous four trials, or semantically unrelated to the previous four trials. Research indicated that language switching did not abolish priming effects, supporting the ICM. These results contradict conclusions found in previous literature. To reconcile this, another experiment was conducted. It was similar to Experiment One, except filler trials separated semantically related trials. Results showed that each time a semantically related neighbor was presented, naming latency increased by ~10ms regardless of language switching or number of filler items. It suggests that the existing literature mistook incremental learning effects as priming effects, and it demonstrates a need to incorporate theories of incremental learning into theories of bilingual language control.

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