Spontaneous state alternations in the time course of mind wandering.

It's a common assumption that people's mental state timeline can be divided into a sequence of focus-mind wandering episodes, each comprises a focusing stage followed by a mind wandering stage. Accordingly, probability of being in a focus state should be high early in an episode and decrease overtime. We investigated the dynamics of shifting between meditation and off task thoughts by systematically probing participants at various time points during a focus-mind wandering episode. Contrary to predictions of the two-stage model, there's no significant decrease in probability of focus state during a focus-mind wandering episode. Simulations matching parameters of each participant suggest that the lack of this negative trend was not due to statistical power. Instead, people may have multiple spontaneous alternations between meditation and off task thoughts before they are able to catch themselves mind wandering. Based on this Multiple Sub-event Model, a novel method was developed to estimate the number of sub-events during a focus-mind wandering episode.

A new approach to differentiate states of mind wandering: Effects of working memory capacity.

Although widely studied, the process of how mind wandering occurs and is subsequently sustained still remains unclear. Moreover, the traditional concept of mind wandering tendency/frequency based on the self- or probe-caught methods alone is incoherent and problematic. We developed a new approach to characterize the mind wandering process by combining the self-caught and probe-caught methods to estimate the time of focus and time of mind wandering separately, and examined their relationship to working memory capacity. Participants performed an OSPAN task and subsequently a basic Mindfulness Meditation Task (focus on breath). During the meditation task, participants indicated when they became aware that they were mind wandering (self-caught method), or were asked if they were mind wandering when probed (probe-caught method). Results showed that time of focus but not time of mind wandering increased with greater working memory capacity. This suggests that individuals with higher working memory capacity were able to focus on the current task longer, but had little effect on the ability to monitor and terminate mind wandering once it occurred. The theoretical and methodological implications of this new approach are discussed.