The impact of bilingualism on working memory: A null effect on the whole may not be so on the parts

Abstract

Abundant research has examined the relationship between bilingualism and working memory (WM), a system that keeps information accessible while dealing with concurrent processes, distractions, or attention shifts (Baddeley & Hitch, 1974; Conway et al., 2002; Engle et al., 1999). Some studies have reported no WM differences between bilinguals and monolinguals (Bialystok, 2010; Bialystok et al., 2008; Bonifacci et al., 2011; Engel de Abreu, 2011; Feng, 2009; Namazi & Thordardottir, 2010), leading top scholars to maintain that this domain is impervious to bilingualism. For instance, Bialystok (2009) first claimed that WM is indifferent to the development of a non-native language (L2). Later, she slightly reframed her position, stating that WM is only occasionally enhanced by the bilingual experience (e.g., Bialystok et al., 2009; Bialystok et al., 2012). Likewise, in another study, Engel de Abreu (2011: 6) concluded that ?bilingual experience does not seem to convey any advantage in working memory abilities,? which aligns with recent criticism on the very notion of bilingual benefits (Calvo et al., 2016; Duñabeitia & Carreiras, 2015; Paap et al., 2016).However, there is no shortage of evidence for enhanced WM in bilinguals. While full-blown WM advantages have been only sparsely reported, several studies yielding no overall benefits did find such effects in specific tasks or conditions. This is also true of comparisons between bilingual groups who daily exert different levels of demand on their WM systems (in particular, simultaneous interpreters vs. non-interpreting bilinguals). These findings indicate that WM is not completely unaffected by the distinctive executive demands of bilingualism. Instead, they suggest that a bilingual advantage may indeed exist in some aspects of WM, as we argue below.