Intrasentential code-switching requires cognitive control in production (Verreyt et al., 2016) as well as comprehension (Adler et al., under review). The first language needs to be inhibited as...Show moreIntrasentential code-switching requires cognitive control in production (Verreyt et al., 2016) as well as comprehension (Adler et al., under review). The first language needs to be inhibited as soon as the second languages is encountered. The neurological system that is associated with cognitive control may stay active for a while after being triggered. Cognitive control is used for any (cognitive) task that requires inhibition, selected attention or decision making. An example of such a task is the Flanker task, in which a participant has to determine the direction of an arrow surrounded by four (congruent or incongruent) distractors. In general, when the arrows all point in the same direction (congruent condition) participants have a shorter reaction time than when the surrounding arrows point in the opposite direction of the target arrow (incongruent condition). The effect of code-switches on Flanker trials has been studied behaviourally. These studies show that processing a code-switch has a positive effect on the reaction time on the incongruent Flanker trials. In this study, we support previous behavioural findings with an electrophysiological investigation of the effect of code-switch detection on cognitive control. We recorded the EEG of 34 participants while they alternated between reading sentences (with and without code-switches) and Flanker trials. In the analysis of the EEG, we were specifically interested in the P300 component, which is associated with shifts in attention. The P300 amplitude is higher when more cognitive control is required (Neuhaus et al., 2010). Since incongruent Flanker trials require more cognitive control than congruent trials, the classic Flanker effect is that the incongruent trials produce a larger P300. However, after being activated by a code-switch, if the cognitive control mechanism indeed stays active for a while, the P300 amplitude of an incongruent Flanker after a code-switch would be lower than one after a sentence without a code-switch. The mean ERP amplitudes were analysed with a 4-way repeated measures ANOVA. Significant interactions were found between sentence type and congruency. There was a significantly larger P300 in the congruent condition than in the incongruent condition, but only when the preceding sentence did not have a code-switch. The P300 was significantly larger after sentences with a code-switch than after sentences without a code-switch, but only in the incongruent condition. There was no effect of sentence type in the congruent condition. These results provide electrophysiological support for previous findings by Adler et al., (under review).Show less