Mind-wandering impedes response inhibition by affecting the triggering of the inhibitory process

Mind-wandering is a state where our mental focus shifts towards task-unrelated thoughts. While it is known that mind-wandering has a detrimental effect on concurrent task performance, e.g., decreased accuracy, its effect on executive functions is poorly studied. Yet, the latter question is relevant to many real-world situations, e.g., rapid stopping during driving. Here we studied how mind-wandering would affect the requirement to subsequently stop an incipient motor response. We tested, first, whether mind-wandering affected stopping, and second, which component of stopping was affected: the triggering of the inhibitory brake or the implementation of the brake following triggering. We observed that during mind-wandering, stopping-latency increased as did the proportion of trials with failed triggering. Indeed, 67% of the variance of the increase in stopping-latency was explained by the increased trigger failures. Thus, mind-wandering affects stopping, primarily by affecting the triggering of the brake.