Attentional Neuroscience Lab, Department of Psychology, University of British Columbia Vancouver, BC, Canada.
Front Hum Neurosci. 2012 Dec 14;6:329. doi: 10.3389/fnhum.2012.00329. eCollection 2012.
Mind wandering episodes have been construed as periods of "stimulus-independent" thought, where our minds are decoupled from the external sensory environment. In two experiments, we used behavioral and event-related potential (ERP) measures to determine whether mind wandering episodes can also be considered as periods of "response-independent" thought, with our minds disengaged from adjusting our behavioral outputs. In the first experiment, participants performed a motor tracking task and were occasionally prompted to report whether their attention was "on-task" or "mind wandering." We found greater tracking error in periods prior to mind wandering vs. on-task reports. To ascertain whether this finding was due to attenuation in visual perception per se vs. a disruptive effect of mind wandering on performance monitoring, we conducted a second experiment in which participants completed a time-estimation task. They were given feedback on the accuracy of their estimations while we recorded their EEG, and were also occasionally asked to report their attention state. We found that the sensitivity of behavior and the P3 ERP component to feedback signals were significantly reduced just prior to mind wandering vs. on-task attentional reports. Moreover, these effects co-occurred with decreases in the error-related negativity elicited by feedback signals (fERN), a direct measure of behavioral feedback assessment in cortex. Our findings suggest that the functional consequences of mind wandering are not limited to just the processing of incoming stimulation per se, but extend as well to the control and adjustment of behavior.
思维漫游被解释为“与刺激无关”的思维时段，此时我们的思维与外部感觉环境分离。在两项实验中，我们使用行为和事件相关电位（ERP）测量来确定思维漫游是否也可以被视为“与反应无关”的思维时段，此时我们的思维不再调整我们的行为输出。在第一个实验中，参与者执行了一项运动跟踪任务，并偶尔被提示报告他们的注意力是“在任务上”还是“思维漫游”。我们发现，在思维漫游前的时期与在任务上的报告相比，跟踪误差更大。为了确定这一发现是由于视觉感知本身的衰减还是思维漫游对绩效监测的干扰效应，我们进行了第二个实验，参与者完成了一个时间估计任务。他们在收到关于估计准确性的反馈的同时记录他们的 EEG，并偶尔被要求报告他们的注意力状态。我们发现，在思维漫游前的时期，行为和 P3 ERP 成分对反馈信号的敏感性以及对反馈信号的错误相关负波（fERN）的反应明显降低，fERN 是大脑皮层对行为反馈评估的直接测量。我们的研究结果表明，思维漫游的功能后果不仅限于对输入刺激的处理本身，还延伸到对行为的控制和调整。
