Cognitive Control: Good Bilinguals, Bad Bilinguals, and Monolinguals

The purpose of this study was to investigate how differences within the bilingual population affect the discovery of a bilingual advantage. One-hundred and one Spanish-English bilinguals and 53 English monolinguals participated in three different tasks. In a verbal picture-naming task bilinguals were required to switch between English and Spanish while naming pictures in quick succession. Errors of interference (EI), in which bilinguals named a picture in the uncued language, were used to divide the bilingual group into non-switchers (few EI) and switchers (many EI). The two bilingual groups were then compared with monolinguals in two non-verbal tasks of cognitive control, a shape-color switching task and a Simon task. In the shape-color switching task participants were required to respond to either the shape or the color of a stimulus, and the rule for response changed following a number of trials by the presentation of a non-verbal cue. In the Simon task, participants were presented with different colored circles in different locations on the screen and were required to disregard location and respond to the color of the circle. Results revealed that monolinguals responded faster than both bilinguals in the shape-color task. In the Simon task, monolinguals responded faster than switcher bilinguals, with the non-switcher bilinguals not significantly different from the monolinguals or the switcher bilinguals. Non-switcher bilinguals were more accurate on the shape-color task than switcher bilinguals, with the monolinguals not significantly different from either bilingual group. These results suggest that bilinguals and monolinguals approach these tasks differently, with bilinguals focused on response selection and accuracy to the detriment of their reaction time. This may be due to the salience of response selection (i.e. language selection) in the bilinguals’ daily lives. Additionally, it was found that some bilinguals (non-switchers) outperformed other bilinguals (switchers), indicating that better performance on a verbal switching task is related to better performance on a non-verbal switching task, but no bilingual advantage was discovered in comparisons of bilinguals and monolinguals.