Monolingualism, bilingualism and executive function of children from low-income families

Previous study of executive function of bilingual children generally shows better executive function among bilinguals (e.g. Bialystok & Martin, 2004). However, only a few research studies have focused on the bilingual influence of executive function in the context of low-income. Because low-income negatively influences children\u27s executive function (Clearfield & Niman, 2012), it is unclear if bilingual children from low-income families could still show advantages in executive function. Therefore, the goal of this dissertation research was to study the executive function of low-income bilingual and monolingual children, in order to gain a better understanding of the difference in executive function between them. Furthermore, the proposed study intended to investigate the difference between simultaneous bilingual children and sequential bilingual children on their executive function, which has not yet been well studied. This study recruited 60 4- to 5-year-old children from Educare of Omaha, NE. The children completed three executive function tasks: Day/Night task (measuring inhibitory control), Nine Boxes task (measuring working memory), and Spatial Reversal task (measuring shifting). Children\u27s English language proficiency was measured by the Preschool Language Scale 5th (PLS) conducted by Educare evaluators. Children\u27s reading stimulation and mother education level was obtained from questionnaire. If no control variables were involved, the results indicated no significant differences between monolingual children and bilingual children or among monolingual, simultaneous bilingual and sequential bilingual children in inhibitory control, working memory or shifting/cognitive flexibility or integral EF. When comparing two bilingual groups, simultaneous bilingual children showed better working memory than sequential bilingual children; while sequential bilingual children showed better shifting ability than simultaneous bilingual children. After controlling children\u27s English language proficiency, reading stimulation and mother\u27s education level, the monolingual children were found to show better working memory ability than bilingual children. Simultaneous bilinguals demonstrated better working memory than sequential bilingual children. For the comparison among the three language groups with control variables added, simultaneous bilingual children showed higher working memory ability than the other two language groups