On the reliability of switching costs across time and domains

Bilingual speakers are suggested to use control processes to avoid linguistic interference from the unintended language. It is debated whether these bilingual language control (BLC) processes are an instantiation of the more domain-general executive control (EC) processes. Previous studies inconsistently report correlations between measures of linguistic and non-linguistic control in bilinguals. In the present study, we investigate the extent to which there is cross-talk between these two domains of control for two switch costs, namely the n-1 shift cost and the n-2 repetition cost. Also, we address an important problem, namely the reliability of the measures used to investigate cross-talk. If the reliability of a measure is low, then these measures are ill-suited to test cross-talk between domains through correlations. We asked participants to perform both a linguistic- and non-linguistic switching task at two sessions about a week apart. The results show a dissociation between the two types of switch costs. Regarding test–retest reliability, we found a stronger reliability for the n-1 shift cost compared to the n-2 repetition cost within both domains as measured by correlations across sessions. This suggests the n-1 shift cost is more suitable to explore cross-talk of BLC and EC. Next, we do find cross-talk for the n-1 shift cost as demonstrated by a significant cross-domain correlation. This suggests that there are at least some shared processes in the linguistic and non-linguistic task.The research leading to these results has received funding from the Dutch Organization for Scientific Research (NWO) with grant 446-14-006 and from the Ministerio de Economía, Industria y Competitividad (MINECO) with the Juan de la Cierva grant (IJCI-2016-28564) awarded to KT. This work was also supported by grants from the Spanish government (PSI2014-52181-P and PSI2017-87784-R), the Catalan government (SGR 2009-1521 and 2017 SGR 268), the La Marató de TV3 Foundation (373/C/2014), and the European Research Council under the European Community’s Seventh Framework (FP7/2007–2013 Cooperation Grant Agreement 613465-AThEME). And last, MC was supported by the postdoctoral Ramón y Cajal fellowship (RYC-2013-14013) and FB was supported by the postdoctoral Marie Sklodowska-Curie fellowship (658341)