Investigating the effects of code-switch types on cognitive control.

Code switching, here defined as the use of two languages within a single sentence, has been hypothesized to engage cognitive control such as inhibition and conflict monitoring. The current project investigates whether structurally distinct types of code switching engage cognitive control differently. We tested this in a conflict adaptation paradigm. Early Spanish-English bilinguals in the United States listened to (Experiments 1, 2, 4) or read (Experiment 3) unilingual Spanish sentences and sentences with dense or insertional switches to English. After each sentence, participants saw a Flanker trial and indicated the direction of the center arrow while ignoring the flanking arrows. If processing code switches increases engagement with cognitive control, then subsequent incongruent Flanker trials should demonstrate a reduced Flanker conflict effect. Across four experiments, we found either no effect of code switching on Flanker performance (Experiment 1) or found that the Flanker conflict effect was larger after code switched than after unilingual sentences (Experiments 2-4). We found no evidence that there was a difference between insertional and dense code switching on the Flanker conflict effect or a difference between modalities. We therefore have no evidence that processing code-switched sentences enhances cognitive control. We interpret our finding in terms of resources: Code switches without an interactive context are unexpected and pragmatically odd. This draws resources and attention away from a following Flanker trial, leading to a larger conflict effect after a code switch. (PsycInfo Database Record (c) 2025 APA, all rights reserved).