Factors influencing bilinguals’ speed and accuracy of number judgments across languages: A meta-analytic review

Abstract

• For bilinguals, number judgments are overall faster and more accurate in the first language. • Early schooling in the first language predicts a first language advantage in number speed and accuracy. • Low or medium second language proficiency predicts a first language advantage in number task performance. • Late onset of bilingualism predicts a first language advantage in number task performance. • The findings support models of number representation that posit language experience-based format effects. Are bilinguals faster and/or better at performing numerical judgments in one language than in their other language? What factors moderate language differences in number processing ease? To address these issues, we conducted a meta-analysis of 38 studies (based on 1861 participants) in which bilinguals’ speeded performance and accuracy on number tasks was compared across languages within subjects. Analysis of 63 independent effect sizes for reaction time data and 28 for accuracy data showed an overall language difference favoring the first language. This effect was particularly observed in reaction time studies for number tasks involving arithmetic judgments or number naming. The L1 effect was characteristic of bilinguals with low or medium proficiency in the second language, those who were schooled in the first language, and those whose stated preference for arithmetic was the first language. Further, a first language advantage was most characteristic of late bilinguals (for reaction time). For accuracy, additional moderators of a first language advantage included differences between the languages in decade unit counting system. No other effects were significant. The findings lend support to models of number cognition that posit format-sensitive codes. They further clarify that a privileging of the first language is not uniform but varies by bilingualism onset, proficiency, language of early schooling, and language-specific characteristics.