Mind wandering occurs when spontaneous thought generation is increased while cognitive control is decreased, presumably in response to antagonistic effects of default mode- (DMN) and goal-directed network (GDN) activity. Previous studies assumed that DMN or GDN activity manifests in behavior with minimal delays and has rigid effects, i.e., DMN always facilitates generation of spontaneous thought and inhibits cognitive control. With those static response functions, the antagonism of DMN and GDN could explain the alternation of task focused and mind wandering states. But it rules out others, such as multi-tasking, where spontaneous thought and cognitive control are both increased, or rumination, where both are decreased. However, shifts from task focused to mind wandering have been shown to occur via a multi-tasking state. We therefore propose dynamic response functions, allowing delay or reversal of DMN and GDN effects. Dynamic response functions enabled us to stochastically predict mind wandering up to at least 30 min in advance from EEG measures of DMN and GDN activity in a tone counting task. Experimental results show both considerable delays and switches between task-positive and negative effects. Mind wandering was initiated by a barrage of DMN activity more than 20 minutes prior a report of mind wandering, directing the mental focus inward. Critically, facilitation of spontaneous thoughts occurred several minutes prior to the report. These thoughts sustained up to 10 min, after which a rebound to task-focused behavior was effectuated, notably without intervention from the GDN. Repeated GDN interventions, however, secured a basic level of task performance.
Dynamic response functions and helical gaps in interacting Rashba nanowires with and without magnetic fields
