Mind Wandering and the Adaptive Control of Attentional Resources Julia W. Y. Kam 1 , Elizabeth Dao 1 , Maria Stanciulescu 1 , Hamish Tildesley 2 , and Todd C. Handy 1 Abstract ■ Mind wandering is a natural, transient state wherein our neuro- cognitive systems become temporarily decoupled from the exter- nal sensory environment as our thoughts drift away from the current task at hand. Yet despite the ubiquity of mind wandering in everyday human life, we rarely seem impaired in our ability to adaptively respond to the external environment when mind wan- dering. This suggests that despite widespread neurocognitive de- coupling during mind wandering states, we may nevertheless retain some capacity to attentionally monitor external events. But what specific capacities? In Experiment 1, using traditional perfor- mance measures, we found that both volitional and automatic forms of visual–spatial attentional orienting were significantly atten- uated when mind wandering. In Experiment 2, however, ERPs re- vealed that, during mind wandering states, there was a relative preservation of sensitivity to deviant or unexpected sensory events, as measured via the auditory N1 component. Taken together, our findings suggest that, although some selective attentional processes may be subject to down-regulation during mind wandering, we may adaptively compensate for these neurocognitively decoupled states by maintaining automatic deviance–detection functions. ■ INTRODUCTION One of the odd quirks of human cognition is that we fre- quently get lost in our own trains of thought, even when doing attention-demanding tasks. When driving, for ex- ample, many people have had that unsettling experience of suddenly realizing that theyʼve been completely tuned out for the past few miles, with little recollection of the traffic and terrain thatʼs been navigated in the interim. But this raises a striking question regarding our natural propensity to have our thoughts drift off-task—how is it that our minds can regularly wander like this during on- going tasks, yet we still seem to retain some capacity to monitor and respond to the external environment? Is some ability to selectively attend to salient events in the outside world actually preserved when in mind wandering states? The question is all the more perplexing given what we know about the effect of mind wandering on stimulus processing in cortex. When in mind wandering states, there is a significant reduction in the extent to which we cognitively analyze or process task-relevant events, relative to when in “on-task” attentional states (e.g., Barron, Riby, Greer, & Smallwood, 2011; Oʼ Connell et al., 2009; Smallwood, Beach, Schooler, & Handy, 2008). Likewise, the initial sensory-evoked cortical activ- ity engendered by task-irrelevant events also decreases, an effect observed in both the visual and auditory domains (e.g., Braboszcz & Delorme, 2011; Kam et al., 2011). Such evidence has suggested that mind wandering facilitates the production and maintenance of internal trains of thought by transiently “decoupling” neurocognitive systems from external stimulus inputs (e.g., Barron et al., 2011; Schooler et al., 2011; Smallwood et al., 2011; Smallwood, Obonsawin, & Heim, 2003). But if our thoughts become decoupled when mind wandering, do our attentional systems de- couple as well? Given this question, the goal of our study was to ex- amine whether controlled or more volitional attentional functions change as we drift in and out of mind wander- ing states, and if so, how this compares to the possible effect of mind wandering on more automatic or reflexive attentional functions. In our first experiment, we thus asked participants to perform two different visual–spatial cuing tasks that required making manual responses to lateralized targets. One task involved volitional spatial orienting (e.g., Posner 1980), and the other task involved reflexive spatial orienting (e.g., Tipper, Handy, Giesbrecht, & Kingstone, 2008; Friesen & Kingstone, 1998). The voli- tional orienting of spatial attention involves individuals voluntarily shifting their attention elsewhere, whereas re- flexive spatial orienting involves an external stimulus that attracts oneʼs attention involuntarily. At unpredictable in- tervals during task performance, we stopped participants and asked them to report on their task-related attentional state-either “on-task” or “mind wandering.” We then exam- ined the RTs to targets as a function of whether they were in cued or uncued spatial locations and whether they immediately preceded an “on-task” versus “mind wander- ing” report. If mind wandering disrupts visual selective 1 University of British Columbia, 2 Dartmouth College © 2013 Massachusetts Institute of Technology Journal of Cognitive Neuroscience 25:6, pp. 952–960 doi:10.1162/jocn_a_00375