Using a foreign language does not make you think more: Null effects of using a foreign language on cognitive reflection and numeracy

Aims and objectives/purpose/research questions: Using a foreign language is suggested to affect how we think, even reducing bias. However, the exact mechanisms of its influence are still unknown. In this project, we tested two variants of the “thinking more” mechanism driving the foreign language effect: increased cognitive reflection and greater task engagement. Design/methodology/approach: We analyzed previously collected data from five experiments employing the Cognitive Reflection Test (CRT) and/or the Berlin Numeracy Test (BNT), each administered in the native or foreign language. If the increased reflection explanation is true, the CRT score should be higher in participants using a foreign language. If the greater task engagement explanation is true, the BNT score should be higher in participants using a foreign language. Data and analysis: We report data from N = 1,288 participants who filled the CRT and N = 413 who filled the BNT. Data were analyzed using the NHST approach and its Bayesian alternative over a spectrum of liberal, default, and conservative priors. Data are publicly available at https://osf.io/m8tn9 Findings/conclusions: All the test results were nonsignificant and showed anecdotal to strong evidence that neither the CRT nor the BNT scores improved in the foreign language condition, also when controlling for proficiency. The proportion of intuitive to computational errors was also unaffected. Originality: We are the first to comprehensively test the thinking-more explanation of the foreign language effect. Significance/Implications: Our results undermine the claim that using a foreign language promotes more cognitive reflection or engagement. The foreign language effect likely has a different cause.