On the Reliability of Switching Costs Across Time and Domains.

Cristina Baus,Marco Calabria,Kalinka Timmer,Albert Costa,Francesca M Branzi

doi:10.3389/fpsyg.2018.01032

Abstract

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.

Highlights

How do bilingual speakers control their two languages to avoid linguistic confusion? Researchers argue that this is achieved by a set of control processes labeled bilingual language control (BLC) (Green, 1998)
We explored the test–retest reliability of linguistic and nonlinguistic switch costs (n-1 shift and the n-2 repetition cost), as well as the presence/absence of cross-talk between the two cognitive control domains for both switch costs
The current study revealed a dissociation between the two types of switch costs (n-1 shift cost and n-2 repetition cost) regarding their test–retest reliability and the cross-talk between domains

Summary

Introduction

How do bilingual speakers control their two languages to avoid linguistic confusion? Researchers argue that this is achieved by a set of control processes labeled bilingual language control (BLC) (Green, 1998). The extent to which this cross-talk between domains is present for switch costs is inconsistent and controversial (Garbin et al, 2010; Branzi et al, 2016a; Timmer et al, 2017). We report a study that explores: (a) the cross-talk between the two systems by looking at switch costs in the two domains, and (b) the reliability of two switching measures often used to explore the cross-talk of control mechanisms between BLC and EC. We argue that the reliability of these measures varies considerably and that when they are reliable, cross-talk between domains is present

Methods

Results

Discussion

Conclusion