On trade-offs in bilingualism and moving beyond the Stacking the Deck fallacy

Abstract

Despite a meteoric rise, results in the cognitive science of bilingualism present with significant inconsistency. In parallel, there is a striking absence of an ecologically valid theory within bilingualism research. How should one interpret the totality of available data that can pull in opposing directions? To proceed, we need to identify which practices impede progression. Hitherto, we bring to the fore an undiscussed practice, contextualizing how it impacts the ability to embed the available results into an overarching theory. We suggest that a stacking the deck fallacy – the tendency to engage differently with available evidence, directing focus to specific sub-samples – hampers theory formation. We put forth a proposal for making progress, building on the premise that what is lacking in the field is a unifying perspective that reconciles seemingly contradictory results. We suggest that the necessary shift of perspective towards progress crucially entails linking the notions of spectrum and trade-off.

Bilingual disadvantages are systematically compensated by bilingual advantages across tasks and populations

“…One well-established cognitive trade-off, for instance, is the speed-accuracy one for which, succinctly put, faster performance taxes responses’ accuracy 41 . This trade-off hypothesis can be conceived as consisting of different ramifications that respond to an environmental trigger (in this case, bilingualism) through playing a zero-sum game 42 : Once we zoom out of individual studies and observe the overall picture in a given population, positive and negative effects (i.e., bilingual advantages and disadvantages) will likely be found to complement each other, striking a balance that optimizes the use of the organism’s finite resources. Such trade-offs are inherent to cognition and life in general 21 , and there is ample evidence of applications of the trade-off hypothesis in different branches of neurocognition or evolutionary ecology 42 .…”

“…This trade-off hypothesis can be conceived as consisting of different ramifications that respond to an environmental trigger (in this case, bilingualism) through playing a zero-sum game 42 : Once we zoom out of individual studies and observe the overall picture in a given population, positive and negative effects (i.e., bilingual advantages and disadvantages) will likely be found to complement each other, striking a balance that optimizes the use of the organism’s finite resources. Such trade-offs are inherent to cognition and life in general 21 , and there is ample evidence of applications of the trade-off hypothesis in different branches of neurocognition or evolutionary ecology 42 . Generally, trade-offs boil down to key, high-level properties of goal-directed systems (e.g., general or task-specific aspects of performance, resilience, efficiency, robustness, and flexibility).…”

Harnessing the bilingual descent down the mountain of life: Charting novel paths for Cognitive and Brain Reserves research

“…Rather, the intention is to appeal to what a simple hike on any mountain evidences: mountains in the real world never have perfectly flat inclines and declines-these only exist in cartoonish renderings and/or can seem as such in photos when the offered perspective comes from a vantage point that is significantly zoomed out. In fact, more generally speaking, it is likely that inconsistencies in heralding the relative zoomed perspective of particular bilingualism and neurocognition studies themselves contribute to misunderstandings that circulate through several debates within the field (Leivada et al, 2021(Leivada et al, , 2023. In any case, the real nature of mountainous climbs and descents entail a series of peaks and valleys, iterative ups and downs taking place along what is otherwise clearly the ascent or the descent.…”

73% of the observed bilingual (dis)advantageous effects on cognition stem from sociolinguistic factors: A systematic review

“…The first one concerns the type of the effects and recognizes three categories of results: bilingual advantages (i.e., positive findings), bilingual disadvantages (i.e., negative findings), and null effects (i.e., findings that suggest that the differences between monolinguals and bilinguals are indistinguishable from zero). Regarding the terminology we use, while we a priori reject the use of evaluative terms such as "bilingual advantage" and "bilingual disadvantage" as simplistic (Leivada et al, 2022), the primary purpose of any systematic review is to take stock. We thus employ these mainstream terms, following a long line of systematic reviews, meta-analyses, and quantitative analyses that adhere to the same practice (Donnelly et al, 2019;Grundy, 2020;Lehtonen et al, 2018;van den Noort et al, 2019;Ware et al, 2020).…”

“…In this respect, another terminological specification should be made about the term "bilingual adaptations", which we use synonymously with the term "bilingual effects". We follow recent literature (e.g., D'Souza & D 'Souza, 2021;Ivanova et al, 2023) that borrowed the term "adaptation" from research on human evolution to highlight that the act of adapting to the surrounding linguistic environment is on par with other ecological adaptations (Leivada et al, 2022). Thus, we use the term "bilingual adaptations" to indicate the offset between advantageous and disadvantageous effects that the bilingual experience has across different cognitive domains, such as executive functions (Bialystok, 2007;Costa et al, 2008 inter alia), semantic fluency (Gollan et al, 2002;Ivanova & Costa, 2008), syntactic processing (Siu & Ho, 2022), and metalinguistic awareness (Adesope et al, 2010).…”