Data trimming procedure can eliminate bilingual cognitive advantage

Abstract

Bilingualism and its cognitive impacts have drawn increasing interest. Recently, inconsistencies in the findings have raised discussions on what might have caused such discrepancies and how evidence should be evaluated. This review tries to shed new light onto the reasons for the inconsistencies by taking a novel perspective. Motivated by the finding that bilingualism affects response time distribution profiles, particularly findings that suggest bilinguals have fewer long responses, we investigated the relation between maximum response times allowed/included in the analysis of an experiment and the finding of a bilingual advantage. We reviewed 68 experiments from 33 articles that compared monolingual and bilingual speakers' performance in three commonly used non-verbal interference tasks (Simon, Spatial Stroop and Flanker). We found that studies that included longer responses in their analysis were more likely to report a bilingualism effect. We conclude that seemingly insignificant details such as the data trimming procedure can have a potential impact on whether an effect is observed. We also discuss the implication of our findings and suggest the usefulness of more fine-grid analytical procedures.

More similitudes than differences between bilinguals and monolinguals on speeded and demand-varying executive tasks

“…In fact, in studies with comparable designs to the current one, results show the opposite pattern (Emmorey et al, 2008;Jiao et al, 2019;Luk et al, 2010). We speculate that faster RTs in monolinguals for the NgF task might stem from the emphasis on speeded trial presentation pace (Zhou & Krott, 2016), which resulted in an enhanced baseline executive control exerted by participants, as compared to that involved in the less speed-demanding tasks usually reported in the BA literature. Thus, we conjecture that bilinguals might experience a general enhanced executive control as a consequence of the lifelong practice they have switching back and forth from one of their languages to the other in changing contexts.…”

“…Hence, task demands shall increase as a function of this temporal limitation (Dambacher & Hübner, 2013;Kiselev, Espy, & Sheffield, 2009;van Veen, Krug, & Carter, 2008). In this sense, we intentionally designed several speeded pace tasks, as compared to those tasks usually employed in the field (Zhou & Krott, 2016), motivated by previous findings suggesting that the BA is more noticeable when tasks are more demanding (Yang & Yang, 2017). Furthermore, the acceleration of the tasks' pace could likely evade the ceiling effect in task performance in young adults and make differences between groups more noticeable.…”

Cultural Effects Rather Than a Bilingual Advantage in Cognition: A Review and an Empirical Study

“…It is telling that despite performing separate analyses for each variable, which increases the chances of discovering a false positive in favor of a bilingual advantage, we still found no evidence to support the hypothesis. Additionally, we were also able to establish through the analysis of control trials that the Korean advantage was not related to general processing speed (Paap, 2017), and we showed that the absence of a bilingual advantage was not related to the trimming of response time data (Zhou & Krott, ). By including a measure of nonverbal IQ as a factor in each model, our findings are also free of this potential confound .…”

The bilingual adaptation: How minds accommodate experience.

“…Other factors that may also prevent the appearance of significant differences between monolingual and bilingual young adults performing executive control tasks have been discussed elsewhere and include the selection and designation of the participants as monolingual or bilingual, the statistical methods used in the analyses, the features of the tasks, and the interpretation of the results (Bak, 2015, 2016; Bialystok, in press; Kroll & Bialystok, 2013; Zhou & Krott, 2016). A full discussion of these factors is beyond the scope of the present review.…”