Dissociating the freely-moving thought dimension of mind-wandering from the intentionality and task-unrelated thought dimensions

Positively framing mind wandering does not increase mind wandering in older adults

Age-related differences in mind wandering are robust, with older adults reporting less mind wandering compared to younger adults. While several theories have been put forth to explain this difference, one view has received less attention than others. Specifically, age-related differences in mind wandering might occur because older adults are reluctant to report on their mind wandering. The aim of the current study was to explicitly test this hypothesis. Older and younger adults completed a go/no-go task with intermittent thought probes to assess mind wandering. In one condition, participants were provided with standard instructions about how to respond to questions about their thoughts. In a second condition, participants were provided with a positive framing of mind wandering. Mind wandering was assessed both subjectively (i.e., via thought probes) and objectively (i.e., using different behavioral measures from the go/no-go task). The results of the study suggest that positively framing mind wandering did not impact rates of mind wandering or objective indicators of mind wandering for older or younger adults. Older adults reported less mind wandering, regardless of condition, compared to younger adults. Older adults also had generally better performance on the go/no-go task compared to younger adults. Bayesian analyses suggested that the main effect of framing condition, although not significant in Frequentist terms, did provide moderate evidence of an overall effect on mind wandering rates. We interpret the results as evidence against the reluctance hypothesis, consistent with previous work.

Comparing attentional disengagement between Prolific and MTurk samples

Attention often disengages from primary tasks in favor of secondary tasks (i.e., multitasking) and task-unrelated thoughts (i.e., mind wandering). We assessed whether attentional disengagement, in the context of a cognitive task, can substantially differ between samples from commonly used online participant recruitment platforms, Prolific and Mechanical Turk (MTurk). Initially, eighty participants were recruited through Prolific to perform an attention task in which the risk of losing points for errors was varied (high risk = 80% chance of loss, low risk = 20% chance of loss). Attentional disengagement was measured via task performance along with self-reported mind wandering and multitasking. On Prolific, we observed surprisingly low levels of disengagement. We then conducted the same experiment on MTurk. Strikingly, MTurk participants exhibited more disengagement than Prolific participants. There was also an interaction between risk and platform, with the high-risk group exhibiting less disengagement, in terms of better task performance, than the low-risk group, but only on MTurk. Platform differences in individual traits related to disengagement and relations among study variables were also observed. Platform differences persisted, but were smaller, after increasing MTurk reputation criteria and remuneration in a second experiment. Therefore, recruitment platform and recruitment criteria could impact results related to attentional disengagement.

Neural representations of self-generated thought during think-aloud fMRI

Is the brain at rest during the so-called resting state? Ongoing experiences in the resting state vary in unobserved and uncontrolled ways across time, individuals, and populations. However, the role of self-generated thoughts in resting-state fMRI remains largely unexplored. In this study, we collected real-time self-generated thoughts during "resting-state" fMRI scans via the think-aloud method (i.e., think-aloud fMRI), which required participants to report whatever they were currently thinking. We first investigated brain activation patterns during a think-aloud condition and found that significantly activated brain areas included all brain regions required for speech. We then calculated the relationship between divergence in thought content and brain activation during think-aloud and found that divergence in thought content was associated with many brain regions. Finally, we explored the neural representation of self-generated thoughts by performing representational similarity analysis (RSA) at three neural scales: a voxel-wise whole-brain searchlight level, a region-level whole-brain analysis using the Schaefer 400-parcels, and at the systems level using the Yeo seven-networks. We found that "resting-state" self-generated thoughts were distributed across a wide range of brain regions involving all seven Yeo networks. This study highlights the value of considering ongoing experiences during resting-state fMRI and providing preliminary methodological support for think-aloud fMRI.

Prefrontal contributions to the stability and variability of thought and conscious experience

The human prefrontal cortex is a structurally and functionally heterogenous brain region, including multiple subregions that have been linked to different large-scale brain networks. It contributes to a broad range of mental phenomena, from goal-directed thought and executive functions to mind-wandering and psychedelic experience. Here we review what is known about the functions of different prefrontal subregions and their affiliations with large-scale brain networks to examine how they may differentially contribute to the diversity of mental phenomena associated with prefrontal function. An important dimension that distinguishes across different kinds of conscious experience is the stability or variability of mental states across time. This dimension is a central feature of two recently introduced theoretical frameworks-the dynamic framework of thought (DFT) and the relaxed beliefs under psychedelics (REBUS) model-that treat neurocognitive dynamics as central to understanding and distinguishing between different mental phenomena. Here, we bring these two frameworks together to provide a synthesis of how prefrontal subregions may differentially contribute to the stability and variability of thought and conscious experience. We close by considering future directions for this work.

Mind wandering at encoding, but not at retrieval, disrupts one-shot stimulus-control learning

The one-shot pairing of a stimulus with a specific cognitive control process, such as task switching, can bind the two together in memory. The episodic control-binding hypothesis posits that the formation of temporary stimulus-control bindings, which are held in event-files supported by episodic memory, can guide the contextually appropriate application of cognitive control. Across two experiments, we sought to examine the role of task-focused attention in the encoding and implementation of stimulus-control bindings in episodic event-files. In Experiment 1, we obtained self-reports of mind wandering during encoding and implementation of stimulus-control bindings. Results indicated that, whereas mind wandering during the implementation of stimulus-control bindings does not decrease their efficacy, mind wandering during the encoding of these control-state associations interferes with their successful deployment at a later point. In Experiment 2, we complemented these results by using trial-by-trial pupillometry to measure attention, again demonstrating that attention levels at encoding predict the subsequent implementation of stimulus-control bindings better than attention levels at implementation. These results suggest that, although encoding stimulus-control bindings in episodic memory requires active attention and engagement, once encoded, these bindings are automatically deployed to guide behavior when the stimulus recurs. These findings expand our understanding of how cognitive control processes are integrated into episodic event files.

Re-examining the effect of motivation on intentional and unintentional task-unrelated thought: accounting for thought constraint produces novel results

It has been proposed that motivating participants to perform well on a cognitive task ought to lead to decreases in rates of intentional, but not unintentional, task-unrelated thought (TUT; a commonly studied variety of mind wandering). However, at odds with this prediction, research has found that increasing motivation results in decreases in both intentional and unintentional TUTs. One possible explanation for this surprising finding is that standard assessments of TUT may inadvertently conflate TUTs with another variety of mind wandering: unconstrained thought. If so, then deconfounding task-unrelated and unconstrained varieties of mind wandering might produce the predicted effect of a decrease in intentional, but not unintentional, TUT when motivation is increased. To explore this possibility, in the present study, participants completed a sustained-attention task after receiving standard instructions (normal-motivation condition) or instructions informing them that they could leave the study early if they achieved a certain level of performance (motivated condition). Throughout the task, we assessed rates of TUT (both intentional and unintentional) and unconstrained thoughts. Consistent with prior work, the results indicated that motivated participants reported being on-task significantly more frequently than non-motivated participants. However, unlike previous work, we found that when deconfounding TUTs and unconstrained thoughts, participants in the motivation condition reported significantly fewer bouts of intentional TUT than those in the non-motivation condition, but no differences in rates of unintentional TUT were observed between groups. These results suggest that (a) motivation specifically targets intentional TUT and (b) standard assessments of TUT conflate task-relatedness and thought constraint.

How deep is the rift between conscious states in sleep and wakefulness? Spontaneous experience over the sleep-wake cycle

Whether we are awake or asleep is believed to mark a sharp divide between the types of conscious states we undergo in either behavioural state. Consciousness in sleep is often equated with dreaming and thought to be characteristically different from waking consciousness. Conversely, recent research shows that we spend a substantial amount of our waking lives mind wandering, or lost in spontaneous thoughts. Dreaming has been described as intensified mind wandering, suggesting that there is a continuum of spontaneous experience that reaches from waking into sleep. This challenges how we conceive of the behavioural states of sleep and wakefulness in relation to conscious states. I propose a conceptual framework that distinguishes different subtypes of spontaneous thoughts and experiences independently of their occurrence in sleep or waking. I apply this framework to selected findings from dream and mind-wandering research. I argue that to assess the relationship between spontaneous thoughts and experiences and the behavioural states of sleep and wakefulness, we need to look beyond dreams to consider kinds of sleep-related experience that qualify as dreamless. I conclude that if we consider the entire range of spontaneous thoughts and experiences, there appears to be variation in subtypes both within as well as across behavioural states. Whether we are sleeping or waking does not appear to strongly constrain which subtypes of spontaneous thoughts and experiences we undergo in those states. This challenges the conventional and coarse-grained distinction between sleep and waking and their putative relation to conscious states. This article is part of the theme issue 'Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'.