The Physiological Mechanism Of Mind Wandering And The Effect Of Mindfulness Meditation On Mind Wandering

Mind wandering(MW),a common phenomenon,has been seen as the task-unrelated thoughts.Sustained attention to response task(SART)was used in the study,but the task does not explore the effect of meta-awareness or meta-cognition on mind wandering.On the basis of the classical SART,we added meta-awareness into SART,participants were informed to press a button at any time if they realized that they were MW.We defined the modified task as meta-awareness SART(MSART).We could acquire as much MW as possible by participants' introspection and probes.In the study,we defined the MW acquired by participants' meta-awareness as meta-awareness MW,while the MW acquired by probes as the passive MW.Mindfulness has a long history,combined with Buddhism meditation,medicine and psychology.Mindfulness meditation is based on mindfulness technology.To live in the present and fully experience the moment is what it emphases.It is a free and open status in consciousness focusing.It advocates an open attitude to accept and focus on the miserable experience.Mindfulness mediation not only relieves depression,anxiety,sleep and neurodegenerative disorder,but also improves attention and memory.There are two studies in the project.To explore the physiological mechanism of MW and the effect of mindfulness meditation on MW.Study 1: To study the physiological mechanism of MW,and the difference between meta-awareness MW and passive MW.We recruited 41 participants by internet forum or ad.We recorded event-related potentials(ERPs)during MSART.Psychology measures consist of Five-Facet Mindfulness Questionnaire(FFMQ),State-Trait Anxiety Inventory(STAI)and Beck Depression Inventory(BDI).Repeated measures ANOVA reveals that during meta-awareness MW,the mean amplitude of N1 in a window of 130-160 ms was significantly reduced at central electrode site compared to non-MW.The mean amplitude in a window of 190-230 ms,we observed that the ERP positive component at about 200 ms after stimulus presentation(P2)was significantly higher over central sites during meta-awareness MW than non-MW,suggesting participants' attention drifted from the current task when they were MW.The mean amplitude of P300 in a window of350 to 450 ms was significantly reduced during passive MW compared to the non-MW.Taking all factors into consideration,we regarded that meta-awareness could be indeed actively involved in MW.We cautiously concluded that the earlier ERPs were related to meta-awareness during MW,and passive MW was related to late ERPs.Physiological mechanisms between meta-awareness MW and passive MW were different.Study 2: To explore the effect of mindfulness meditation on MW and vigilance.A mixed 2(groups: mindfulness training group and wait-list control group)×2(time:pretest and posttest)design,35 participants were randomized to the mindfulness training group(20 participants)and wait-list control group(15 participants).MSART and psychomotor vigilance test(PVT)were used in the study,PVT was accomplished before MSART.We recorded ERPs during MSART at pretest and posttest both mindfulness training group and wait-list control group.Psychology measures consist of FFMQ,STAI,BDI and Self Consistency and Congruence Scale(SCCS).A mixed 2(groups:mindfulness training group and wait-list control group)×2(time: pretest and posttest)repeated measures ANOVA of FFMQ with time as within-subjects and group as between-subjects factors yielded a significant time by group interaction,then we conducted a follow-up simple effect analysis,mindfulness training group had higher FFMQ total scores at posttest than they did at pretest.We also found non-judging of inner experience(NJ),a factor of FFMQ,yielded a significant time by group interaction,and simple effect analysis showed that the mindfulness training group had higher NJ scores at posttest than pretest.Observing(OB)and describing(DS)had a significant main effect by time,then the paired t test found that the mindfulness training group OB and DS scores of posttest were significantly higher than the pretest.A mixed 2(groups:mindfulness training group and wait-list control group)×2(time: pretest and posttest)repeated measures ANOVA of SAI with time as within-subjects and group as between-subjects factors found a significant time by group interaction,but the simple effect showed the score of wait-list control group at posttest was significantly increased.We found a marginal significant time by group interaction of TAI,but the simple effect found a significant decrease of score of mindfulness training group at posttest.The repeated measures ANOVA of BDI and SCCS had not found significant change between mindfulness training group and wait-list control group.Repeated measures ANOVA of meta-awareness MW found a significant time by group interaction,meta-awareness MW of mindfulness training group was significantly reduced at posttest compared to pretest.It is an undeniable fact that MW of mindfulness training group(both meta-awareness MW and passive MW)was significantly decreased after mindfulness meditation training,but the wait-list control group was not significantly reduced.A mixed 2(groups: mindfulness training group and wait-list control group)×2(time:pretest and posttest)repeated measures ANOVA of RT of PVT with time as within-subjects and group as between-subjects factors yielded a significant time by group interaction,and the simple effect analysis found that RT of PVT of the mindfulness training group was significantly reduced.Repeated measures ANOVA revealed that the mean amplitude of N2 of mindfulness training group at posttest in a window of 180-220 ms at occipital electrode site was significantly higher than pretest.Repeated measures ANOVA also found that the mean amplitude of mismatch negativity(MMN)of mindfulness training group in a window of 100-150 ms at central electrode site at posttest was significantly increased compared to the pretest.Our findings suggested that mindfulness meditation could reduce MW and improve vigilance and attention.N2 and MMN may be the potential physiological mechanism that mindfulness meditation improves attention and vigilance.Taking into account all these findings,we considered that meta-awareness could be indeed actively involved in MW,and earlier ERPs were related to meta-awareness during MW.The mechanisms between meta-awareness MW and passive MW were different,suggesting that MW should be classified in the future study.Mindfulness meditation could significantly improve attention and vigilance,and N2 and MMN may be the essential factors that mindfulness meditation improves attention.