%ALopez, B.%AZhang, M.%AArredondo, M.%AKim, S.%Anull Ed.%BJournal Name: The international journal of bilingualism; Journal Volume: 25; Journal Issue: 1 %D2021%I %JJournal Name: The international journal of bilingualism; Journal Volume: 25; Journal Issue: 1 %K %MOSTI ID: 10296801 %PMedium: X %TThe Simon effect in bilingual language brokers: A role for emotion and proficiency %XAims and objectives/purpose/research questions: Language brokering (LB) is an informal translation experience where bilinguals serve as linguistic and cultural intermediaries for family members. LB may have long-term socio-emotional and cognitive outcomes, yet little is known about its effects on executive functions (EFs). This study examines how first language (L1) proficiency and negative emotions tied to language brokering experiences affect EF performance on a Simon task (ST). Design/methodology/approach: Fifty-three Mexican American Spanish–English bilinguals with LB experience performed a ST, and reported their feelings towards LB for their mother. Data and analysis: Mean reaction times (RTs) and accuracy rates for correct ST trials were analyzed using linear mixed effects modeling, with trial type, proficiency and negative emotions tied to LB experience as factors and their interactions as additional predictors. Findings/conclusions: The L1 proficiency and negative emotions tied to brokering experiences have divergent, but combined effects on EF. Contrary to our hypotheses, low L1 proficiency predicted better performance and the smallest Simon effect was found for brokers with low L1 proficiency and low negative emotional brokering experiences. However, high L1 proficiency predicted better performance (smallest RTs) regardless of negative emotions tied to brokering experiences. Originality: This study takes a different perspective on the examination of individual differences among bilinguals, in which we examine how negative emotions tied to brokering experiences coupled with L1 proficiency relates to EF performance. Significance/implications: Our results provide support for the need to understand how individual differences in bilingual language experiences, such as L1 proficiency and negative emotions tied to LB, interact with performance on the ST. %0Journal Article