mind wandering psychology definition

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• Review Article
• Published: 22 September 2016

Mind-wandering as spontaneous thought: a dynamic framework

• Kalina Christoff 1 , 2 ,
• Zachary C. Irving 3 ,
• Kieran C. R. Fox 1 ,
• R. Nathan Spreng 4 , 5 &
• Jessica R. Andrews-Hanna 6  

Nature Reviews Neuroscience volume  17 ,  pages 718–731 ( 2016 ) Cite this article

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• Cognitive control
• Schizophrenia

In the past 15 years, mind-wandering has become a prominent topic in cognitive neuroscience and psychology. Whereas mind-wandering has come to be predominantly defined as task-unrelated and/or stimulus-unrelated thought, we argue that this content-based definition fails to capture the defining quality of mind-wandering: the relatively free and spontaneous arising of mental states as the mind wanders.

We define spontaneous thought as a mental state, or a sequence of mental states, that arises relatively freely due to an absence of strong constraints on the contents of each state and on the transitions from one mental state to another. We propose that there are two general ways in which the content of mental states, and the transitions between them, can be constrained.

Deliberate and automatic constraints serve to limit the contents of thought and how these contents change over time. Deliberate constraints are implemented through cognitive control, whereas automatic constraints can be considered as a family of mechanisms that operate outside of cognitive control, including sensory or affective salience.

Within our framework, mind-wandering can be defined as a special case of spontaneous thought that tends to be more deliberately constrained than dreaming, but less deliberately constrained than creative thinking and goal-directed thought. In addition, mind-wandering can be clearly distinguished from rumination and other types of thought that are marked by a high degree of automatic constraints, such as obsessive thought.

In general, deliberate constraints are minimal during dreaming, tend to increase somewhat during mind-wandering, increase further during creative thinking and are strongest during goal-directed thought. There is a range of low-to-medium level of automatic constraints that can occur during dreaming, mind-wandering and creative thinking, but thought ceases to be spontaneous at the strongest levels of automatic constraint, such as during rumination or obsessive thought.

We propose a neural model of the interactions among sources of variability, automatic constraints and deliberate constraints on thought: the default network (DN) subsystem centred around the medial temporal lobe (MTL) (DN MTL ) and sensorimotor areas can act as sources of variability; the salience networks, the dorsal attention network (DAN) and the core DN subsystem (DN CORE ) can exert automatic constraints on the output of the DN MTL and sensorimotor areas, thus limiting the variability of thought; and the frontoparietal control network can exert deliberate constraints on thought by flexibly coupling with the DN CORE , the DAN or the salience networks, thus reinforcing or reducing the automatic constraints being exerted by the DN CORE , the DAN or the salience networks.

Most research on mind-wandering has characterized it as a mental state with contents that are task unrelated or stimulus independent. However, the dynamics of mind-wandering — how mental states change over time — have remained largely neglected. Here, we introduce a dynamic framework for understanding mind-wandering and its relationship to the recruitment of large-scale brain networks. We propose that mind-wandering is best understood as a member of a family of spontaneous-thought phenomena that also includes creative thought and dreaming. This dynamic framework can shed new light on mental disorders that are marked by alterations in spontaneous thought, including depression, anxiety and attention deficit hyperactivity disorder.

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Acknowledgements

The authors are grateful to R. Buckner, P. Carruthers, M. Cuddy-Keane, M. Dixon, S. Fazelpour, D. Stan, E. Thompson, R. Todd and the anonymous reviewers for their thoughtful feedback on earlier versions of this paper, and to A. Herrera-Bennett for help with the figure preparation. K.C. was supported by grants from the Natural Sciences and Engineering Research Council (NSERC) (RGPIN 327317–11) and the Canadian Institutes of Health Research (CIHR) (MOP-115197). Z.C.I. was supported by a Social Sciences and Humanities Research Council of Canada (SSHRC) postdoctoral fellowship, the Balzan Styles of Reasoning Project and a Templeton Integrated Philosophy and Self Control grant. K.C.R.F. was supported by a Vanier Canada Graduate Scholarship. R.N.S. was supported by an Alzheimer's Association grant (NIRG-14-320049). J.R.A.-H. was supported by a Templeton Science of Prospection grant.

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A mental state, or a sequence of mental states, including the transitions that lead to each state.

A transient cognitive or emotional state of the organism that can be described in terms of its contents (what the state is 'about') and the relation that the subject bears to the contents (for example, perceiving, believing, fearing, imagining or remembering).

Thoughts with contents that are unrelated to what the person having those thoughts is currently doing.

Thinking that is characteristically fanciful (that is, divorced from physical or social reality); it can either be spontaneous, as in fanciful mind-wandering, or constrained, as during deliberately fantasizing about a topic.

A thought with contents that are unrelated to the current external perceptual environment.

A deliberate guidance of current thoughts, perceptions or actions, which is imposed in a goal-directed manner by currently active top-down executive processes.

The emotional significance of percepts, thoughts or other elements of mental experience, which can draw and sustain attention through mechanisms outside of cognitive control.

Features of current perceptual experience, such as high perceptual contrast, which can draw and sustain attention through mechanisms outside of cognitive control.

The process of spontaneously or deliberately inferring one's own or other agents' mental states.

Flexible combinations of distinct elements of prior experiences, constructed in the process of imagining a novel (often future-oriented) event.

A type of dreaming during which the dreamer is aware that he or she is currently dreaming and, in some cases, can have deliberate control over dream content and progression.

The ability to produce ideas that are both novel (that is, original and unique) and useful (that is, appropriate and meaningful).

A method in which participants are probed at random intervals and asked to report on aspects of their subjective experience immediately before the probe.

Different ways of categorizing a thought based on its contents, including stimulus dependence (whether the thought is about stimuli that one is currently perceiving), task relatedness (whether the thought is about the current task), modality (visual, auditory, and so on), valence (whether the thought is negative, neutral or positive) or temporal orientation (whether the thought is about the past, present or future).

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Christoff, K., Irving, Z., Fox, K. et al. Mind-wandering as spontaneous thought: a dynamic framework. Nat Rev Neurosci 17 , 718–731 (2016). https://doi.org/10.1038/nrn.2016.113

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Article Contents

Introduction, mind wandering, cognitive control, why the mind wanders, explanations, predictions, philosophical implications, acknowledgments.

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Why does the mind wander?

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Joshua Shepherd, Why does the mind wander?, Neuroscience of Consciousness , Volume 2019, Issue 1, 2019, niz014, https://doi.org/10.1093/nc/niz014

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I seek an explanation for the etiology and the function of mind wandering episodes. My proposal—which I call the cognitive control proposal—is that mind wandering is a form of non-conscious guidance due to cognitive control. When the agent’s current goal is deemed insufficiently rewarding, the cognitive control system initiates a search for a new, more rewarding goal. This search is the process of unintentional mind wandering. After developing the proposal, and relating it to the literature on mind wandering and on cognitive control, I discuss explanations the proposal affords, testable predictions the proposal makes, and philosophical implications the proposal has.

Makes a novel and empirically tractable proposal regarding why the mind wanders

Offers novel explanations of data on mind wandering

Offers predictions for future work on mind wandering

Integrates literature on cognitive control with the literature on mind wandering

Discusses implications for a philosophical account of the nature of mind wandering

Minds wander

Some wander more than others, but human ones wander a lot. A much-cited estimate, due to Killingsworth and Gilbert (2010) , has it that the awake human mind spends from a third to half its time wandering. That’s a big range, a rough estimate, and there are good reasons to be suspicious of it (see Seli et al. 2018 ). The actual number will likely depend a bit upon the nature of mind wandering, a bit upon whether we have the right measure to produce such an estimate, and of course a bit on individual variability. Estimates aside, though, introspection reports that the mind wanders surprisingly often. My question here is this.

Why does it happen?

Sub-questions include the following. What drives the mind to wander? Does anything drive it to wander? Is the transition from focused thought to meandering thought random? Is it a failure of control, or is there some dark purpose behind these mental movements?

In the next section, I set the table by discussing a few interesting features of mind wandering, as well as a few recent proposals about its etiology, and its function. It is easy to conflate these two, since if mind wandering has a function its etiology may very well help illuminate it, but the questions are distinct. Here, I am more interested in why mind wandering happens—about its etiology. It turns out, though, that on my proposal mind wandering happens for good functional reasons. I develop this proposal, which I call the cognitive control proposal, in Cognitive control and Why the mind wanders sections. In Explanations section, I discuss some explanations this proposal makes possible. In Predictions section, I discuss some predictions that could confirm or disconfirm the proposal. In Philosophical implications section, I discuss implications for a philosophical account of the nature of mind wandering.

By referring to this phenomenon as mind wandering, a term familiar to the lay person, we hope to elevate the status of this research into mainstream psychological thinking (946).

As Murray et al. (2019) report, since that review, usage of “mind wandering” has risen dramatically. Only the Smallwood and Schooler paper used the term in a title or abstract in 2006. In 2018, the term appeared in 132 titles or abstracts.

Increased attention to the range of phenomena grouped together by “mind wandering” is salutary. But theorists recognize that the range of processes the term groups may contain multiple etiologies and processing signatures. Accordingly, theorists have proposed many sub-types of mind wandering, categorizing episodes of mind wandering in at least three distinct ways.

The first two involve a conception of mind wandering as defined in part by the contents of a mind-wandering episode, where the contents are unrelated to a task an agent was performing, or was supposed to perform. But there are various ways for an agent to engage in task-unrelated thought. Some categorize mind-wandering episodes in terms of a relationship to an agent’s intention: mind wandering might occur intentionally or unintentionally ( Giambra 1995 ; Seli et al. 2016 ). A second way to categorize mind-wandering episodes is in terms of a relationship to external stimuli. One might here distinguish between distraction, when the mind is prompted to wander by external stimuli, and mind wandering, when the mind is prompted to wander by internal processes, independently of any particular stimuli (see Stawarczyk et al. 2013 ). Or one could argue that distraction, especially sustained distraction, is a legitimate mind wandering as well.

A third way to characterize mind wandering is not in terms of its contents, but rather its dynamics. So, e.g., Christoff et al. (2016) characterize mind wandering as a species of spontaneous thought, with distinct dynamics. Mind wandering is distinguished from creative thought, and rumination, and other types of mental episodes, by relation to the presence or absence of various constraints on the episode (e.g., what they call “deliberate” and “automatic” constraints).

From a certain height, it appears that these different characterizations may not be in competition. Perhaps there are many routes to mind wandering. Perhaps some of them overlap. Perhaps different questions can be answered by focusing on certain routes in certain contexts. Reasonably, Seli et al. (2018) have recently argued in favor of mind wandering as a natural kind, with different sub-types grouped together by relations akin to family resemblance: “We propose that the field acknowledge mind-wandering to be a multidimensional and fuzzy construct encompassing a family of experiences with common and unique features” (2018, 482).

Methodological and conceptual clarity will simply require, in empirical manuscripts, something like the following sentence: “Here, we conceptualized mind-wandering as ________, and operationally defined it for our participants as ________.” Critically, this approach allows researchers the freedom to study whatever features of mind-wandering they wish, while providing the required specificity about aspects of the experience being explored. (488)

In the same spirit, I note here the sub-type of mind wandering that concerns me. I am interested in unintentional mind wandering—episodes of mind wandering that are neither initiated nor governed by any reportable intention of the agent. This category may cross-cut any relationship to external stimuli, in the sense that unintentional mind wandering could be externally or internally initiated. And it may demonstrate dynamics that are distinct from other sub-types of mind wandering.

Unintentional mind wandering could in principle happen non-consciously. But the literature on human mind wandering has it pegged as a feature of the conscious mind. That is to say, when the mind wanders, what wanders is the stream of consciousness—processes of conscious mentation. So, one key way to study mind wandering is to ask people whether or how often their mind has wandered. People offer reports about it. They recognize that they have been mind wandering. This is not because of mind wandering’s phenomenological signature. It is rather because people have a sense that they were once up to something, and then, more or less unbeknownst to them, they began to be up to something else. Thomas Metzinger (2013) speaks of this as the self-representational blink: an unnoticed shift from pursuing one task to doing whatever it is we do when the mind wanders. Recognizing that your mind has been wandering is always slightly surprising, because you did not plan for things to go in that way. From your perspective, it seems that they just did .

This is puzzling. But calling a mental episode unintentional need not imply that mind wandering is maladaptive, or that it has no function. Indeed, the very frequency with which it occurs had led many to suggest that it must have some functional role (e.g., Baird et al. 2011 ). It may not, of course. Perhaps, we survive in spite of how mentally addled we all are. But it is at least plausible that there is a function.

Some accounts of mind wandering might be taken to deny this. McVay and Kane (2010a ) and Kane and McVay (2012) , e.g., have argued that mind wandering reflects a failure of executive control. They note that a negative correlation exists between working memory capacity and a tendency to experience task-unrelated thoughts (see also Randall et al. 2014 ). Some such correlation is plausible. When one experiences task-unrelated mentation, something has clearly gone wrong. One has failed to stay on task.

But this also fails to imply that mind wandering has no function. Kane and McVay note that the correlation between working memory capacity and task-unrelated thought is not terribly strong: “WMC accounts for only about 5% of the variability in [task-unrelated thought] TUT rates (and vice versa)” (2012, 352). It is possible that mind wandering is both a failure in one sense and adaptive in another.

[W]e found evidence for the hypothesis that cognitive control abilities are specifically involved in the flexible adjustment of mind-wandering to task demands. As was hypothesized, high-WMC participants showed higher levels of TUT adjustment than did low-WMC participants. Thus, a more flexible coordination of the stream of thought appears to be characteristic of high-WMC individuals: They engage in TUTs when situational demands are low but reduce TUTs in attention-demanding situations. (1313)

This hypothesis is consistent with work that has demonstrated that as cognitive control resources diminish with age, the propensity to mind wander diminishes as well ( Maillet and Schacter 2016 ).

If we are to believe that mind wandering is associated with deployments of cognitive control, we need evidence that when agents mind wander, they engage in thought processes that may be beneficial. Some evidence for this is that when agents mind wander, their thoughts very frequently go to non-occurrent goals and needs, and to mentation about how to satisfy these goals in the future ( Klinger 1999 ; Baird et al. 2011 ).

Indeed, as Irving and Thompson (2019) note, it seems that it is possible to manipulate the content of mind wandering episodes by giving agents specific goals. Morsella et al. (2010) told some participants they would, in the near future, have to answer questions about the states in America. Then they gave the participants a different task. About 70 percent of these participants’ task-unrelated thoughts were about U.S. geography. Similarly, Mac Giolla et al. (2017) gave some participants a real future task, and told different participants to only pretend to have (or to lie about having) the same future task. Those participants with genuine intentions reported much more spontaneous thought about the future task than participants without genuine intentions.

It is also possible to manipulate mind wandering by reminding agents of their goals. Kopp et al. (2015) had participants either construct a list of their plans for the week or list features of a car. Participants then performed a reading task. Participants who had just reviewed a set of their own plans and goals reported much more mind wandering during the reading.

There is thus an apparent tension within mind wandering. When the mind wanders (at least unintentionally), agents are distracted from the current task, and performance suffers. But when the mind wanders, it tends to find non-occurrent goals the agent possesses, generating planning that could be beneficial. What’s more, greater cognitive control is associated with increases in mind wandering, especially when task demands are low.

Recall my original question: why does the mind wander? Two related questions that could help: What causes it to start, and what explains what happens as it wanders?

My proposed answer runs through recent work on cognitive control, and on what kinds of mechanisms drive allocations of cognitive control resources. I discuss this work in the next section.

A remarkable feature of the human cognitive system is its ability to configure itself for the performance of specific tasks through appropriate adjustments in perceptual selection, response biasing and the on-line maintenance of contextual information. The processes behind such adaptability, referred to collectively as cognitive control … ( Botvinick et al. 2001 , 624)

Rouault and Koechlin likewise emphasize processes of regulation towards certain ends: “Cognitive control refers to mental processes that evolve as regulating adaptive behavior beyond basic reinforcement and associative learning processes” (2018, 106).

There is a danger here, analogous to the one just discussed regarding definitions of mind wandering, in including far too many process-types under the same heading. “Cognitive control” includes processes like the construction and maintenance of a task set, the switching from one task set to another, the deployment of attention in various ways, the deployment of inhibition, and the monitoring of an agent’s progress towards goal achievement. To get better at understanding how these processes work together (or don’t), it helps to have a label. But the nature of the system is only loosely delineated.

Given this, there is room for differing emphases. So, e.g., Adele Diamond characterizes cognitive control processes as “a family of top-down mental processes needed when you have to concentrate and pay attention, when going on automatic or relying on instinct or intuition would be ill-advised, insufficient, or impossible” (136). This characterization is useful, but not definitive. For the kind of cognitive control processes, I have in mind here might be considered top-down, but do not activate only when agents need to deploy attention. These processes operate outside of the agent’s awareness, influencing the agent’s thought and action in subtle and difficult to detect ways.

So, e.g., Kurzban et al. (2013) have argued that one subtle way cognitive control mechanisms influence thought and action is by generating an experience of effort related to the performance of some task. They hypothesize that the experience of effort is the result of sub-personal computations that determine the current task’s value, as well as the value of nearby available tasks, and output a determination of the opportunity cost of persisting on the current task. The experience of effort is hypothesized to be a signal to the agent to switch tasks.

Kurzban et al. ’s proposal has received a lot of attention. Few agree with all of the specifics, but most agree with the general perspective that sub-personal monitoring mechanisms are concerned to determine the value of succeeding in the current task, as well as the cost of continuing engagement in the current task, and are concerned to, in some sense, direct the agent or her cognitive control resources in a more fruitful way.

Perhaps the most mature theory characterizing the mechanisms that constitute the allocation of cognitive control is the Expected Value of Control theory (see Shenhav et al. 2013 , 2017 ). The general idea is that the cognitive control system “specifies how much control to exert according to a rational cost-benefit analysis, weighing these effort costs against attendant rewards for achieving one’s goals” ( Lieder et al. 2018 , 2). Lieder et al. add to this idea a sophisticated model of how the cognitive control system might come to learn the value of the various control signals it can deploy, and might rely upon what it learns to guide cognition in adaptive ways.

Lieder et al. characterize the position the cognitive control system is typically in as a Markov decision process, specified over certain parameters, driven by reinforcement learning. Those parameters are the initial state of the system, the set of states the system could be in, the set of possible actions (or moves, or operations) the system could take, the conditional probabilities of transitioning between states, and a reward function. Lieder et al. further characterize the actions the system could take as “control signals that specify which computations the controlled systems should perform” (4).

Given this setup, the main aim is to maximize reward via the specification of control signals. The way the system does this is by way of learning algorithms. The system builds and updates a model that specifies transition probabilities between states given different control signals, and that maps these probabilities onto a reward function. The reward function balances the reward associated with an outcome (a new state), together with the computational costs of specifying the computation required to drive the system towards the outcome. So, what the system is designed to do is to take the action (specify the control signal or the package of control signals) that has the highest expected value, given the probabilities of where the action takes the system, and the costs of taking the action.

The hypothesis here is that “the cognitive control system learns to predict the context-dependent value of alternative control signals” (5), and that these predictions determine which actions the system takes.

In cases in which the context is relatively well-known, Lieder et al. posit that the system will depend upon relationships between features of the internal state of the agent and features of the context, and will perform weighted sum calculations to determine the value of various possible actions. Cases in which the context is not well-known are more difficult. But Lieder et al. propose that in such cases the system may utilize exploration strategies to teach itself the value of various actions in the novel situation. These exploration strategies involve drawing samples of the value of control signals in previously encountered contexts, averaging over them, and again selecting the control signal that provides the highest expected value.

Lieder et al. note that “This model is very general and can be applied to model cognitive control of many different processes” (6). And they offer a proof of concept for it, by demonstrating that their model outperforms alternative models across a range of processing types.

These processing types involve learning what features of a task are predictive of reward. Some of them are quite simple. One task on which their model performed well-involved learning where to allocate attention, based upon variable reward offered for attending to different locations. A second task involved learning the difference between colors that indicate reward, and colors that do not. That the model predicts basic learning of this sort is good, but not too surprising.

The expected value of computation depends not only on the rewards for correct performance but also on the difficulty of the task. In easy situations, such as the congruent trials of the Stroop task, the automatic response can be as accurate, faster, and less costly than the controlled response. In cases like this, the expected value of exerting control is less than the EVOC of exerting no control. By contrast, in more challenging situations, such as incongruent Stroop trials, the controlled process is more accurate and therefore has a positive EVOC as long as accurate performance is sufficiently important. Therefore, on incongruent trials the expected value of control is larger than the EVOC of exerting no control. Our model thus learns to exert control on incongruent trials but not on congruent trials. Our model achieves this by learning to predict the EVOC from features of the stimuli. This predicts that people should learn to exert more control when they encounter a stimulus feature (such as a color or word) that is predictive of incongruence than when they encounter a feature that is predictive of congruence. (19)

Of course, agents are rarely aware that a system (or coordinated collection of mechanisms) within them is busy learning the value of different modes of responding, and guiding the way that they deploy cognitive control resources. We are not here explaining explicit deliberation or planning. But we are getting insight into the processes—sub-personal, if you like—that create the cognitive ocean in which more explicit processes swim. What’s more, we are getting insight into the kinds of learning that drive cognitive control operations that agents have to simply live with. Shifts of attention, pulls to engage in various computational operations, a sense of what operations are valuable in what contexts—these are rarely things we explicitly consider. Rather, we depend upon this background to engage in explicit cognition and intentional action.

With this as background, I can suggest an interesting possibility, leading to a proposal regarding the etiology and function of mind wandering.

The possibility is this. Depending on the cognitive control system’s model of the value of various control signals, in cases containing relatively little expected value the system may select a package of control signals leading to exploration. These would be cases in which the goal is to find a new and better goal. And the method, which remains here unclear—although one could imagine it involving shifts of attention, construction of task sets involving imagination, inhibition of current goals, etc.—might be generally described as disengagement from the present task in order to set out upon a search for a more valuable task.

The cognitive control proposal, then, is this. Mind wandering is caused by the cognitive control system precisely when, and because, the expected value of whatever the agent is doing—usually, exercising control towards the achievement of some occurrent goal—is deemed too low, and this “too low” judgment generates a search for a better goal, or task. Perhaps, e.g., the estimation of expected value dips below a value threshold attached to the package of control signals that generate exploration for another goal, or task. Or perhaps the value is always computed in comparison with available options, such that mind wandering is sometimes initiated even in the face of a rewarding current task.

This is a straightforwardly empirical proposal, and should be assessed in terms of the explanations it affords, and by whether the predictions it makes are confirmed or disconfirmed. Before I discuss explanation and prediction, however, I wish to note two things.

First, it would certainly be useful if the cognitive control system contained such an operation. Humans are sophisticated agents, with multiple needs and goals potentially in play in most waking life situations. Fixation on one goal alone, or working towards the satisfaction of one goal at a time, is not a great strategy for flourishing. For, first, if one gets stuck on a difficult goal, or if it becomes apparent (i.e. apparent at least to some system tasked with calculating such a thing) that the present goal is not as rewarding as once calculated, it is much wiser to disengage and seek a better goal. And, second, in many situations progress towards multiple goals at once is possible. All one needs is the capacity to divide attention somewhat, or the capacity to hold multiple goals in mind—or at least within some accessible place—and one might waste much less time. Notice, further, that the above points may hold even if dividing the mind amongst multiple goals leads to performance decrements. Perfect performance is not always required. So long as mediocre performance allows one to satisfy goals and needs, accepting mediocre performance will be a good strategy.

Second, explicit cognitive control already does contain such an operation. Sometimes a task becomes too effortful, too uncomfortable, or too boring. Sometimes—after one has just awakened from a long nap, e.g.—there’s no obvious task at hand. In such cases performing a search for a high-value goal is a familiar operation that we perform explicitly. In other cases, we do not leave behind the current task, but we rather utilize deliberation, prospection, imagination, and other processes in order to find sub-goals, or means to achieve the goal that is currently structuring behavior. These modes of exploration towards discovery of a high-value goal are explicit. Our question here is whether the cognitive control system implicitly—i.e., in the absence of an explicit or conscious formation of intention to do so—initiates mind wandering as a similar mode of exploration, and for similar reasons. The proposal is that it does.

Here are explanations this proposal affords.

First, this proposal offers an explanation for the initiation of mind wandering episodes. These episodes are initiated without the agent’s explicit consent. But they do frequently occur. One possible explanation is that the agent necessarily loses control in these instances. That characterizes the initiation of a mind wandering episode as random. A better explanation, I submit, is that while the initiation of a mind wandering episode is, in one sense, a failure—a failure of the current goal and task set to persist—it is, in another sense, a smart move. It is smart because it results from a cognitive control system that is more or less constantly attempting to determine the value of selecting packages of control signals, and that will act when discrepancies in value are calculated. Note, incidentally, that this could be extended to cases in which the agent is pursuing no particular goal, or has no current task. The system need not always compare value between goals. It might be useful, e.g., to tag expected levels of reward to particular environments, perhaps by averaging over the kinds of rewards an environment-type provides. If agents associate one type of environment—a party, e.g.,—to a plethora of rewarding experiences, then a signal that this environment is near—one can hear party music, e.g.,—might lead the mind to wander in the direction of the kinds of experiences the rewarding environment provides.

The fact that the initiation of mind wandering episodes is smart helps to additionally explain a second fact, namely, that agents with higher levels of cognitive control mind wander more frequently when the current task is easy or non-rewarding.

This is not to deny that mind wandering episodes may sometimes be initiated by affectively salient stimuli, or other distractors. Nor is it to deny the existence of completely unguided, or otherwise guided, episodes of mind wandering. I am not in a position to deny that, e.g., a case of spreading activation in a semantic network could qualify as unintentional mind wandering. It may very well be—indeed it seems plausible—that only some cases of unintentional mind wandering are controlled in the way I here propose. Note, however, that even if this is right, the cognitive control system may be able to interact with uncontrolled mind wandering processes. In some cases, uncontrolled mind wandering could be commandeered if a valuable goal suggests itself.

Third, this proposal offers an explanation for the fact that mind wandering episodes tend to go to other goals the agent possesses. This is a natural place for a process to go if that process is structured by an aim to find a more rewarding goal than the one from which the agent has just disengaged. For it will be much more cost-effective to find existent goals, perhaps by querying memory, than to explore the environment and to construct entirely new goals (although of course this may happen, especially when the environment easily affords novel and rewarding goals).

Fourth, this proposal might be integrated with extant explanations of aspects of mind wandering. Consider, e.g., the decoupling hypothesis ( Antrobus et al. 1970 ; Smallwood et al. 2003 ; Smallwood and Schooler 2006 )—the idea that once mind wandering is underway, domain-general cognitive processes are engaged to maintain the mind wandering episode, by keeping attention decoupled from perceptual input, and by aiding the “continuity and integrity” of the agent’s train of thought ( Smallwood 2013 , 524). As Smallwood (2013) notes, the decoupling hypothesis does not seek to explain the initiation of mind wandering. The cognitive control proposal is consistent with it. That is, the proposal is consistent with domain-general resources being deployed to assist mind wandering episodes. The main comment I wish to make here is that the decoupling hypothesis becomes more plausible, and data on the deployment of domain-general resources in mind wandering more transparent, if the entire process of mind wandering can be seen as goal-directed, where the goal is set by the cognitive control system.

This proposal is also consistent with work on the recruitment of neural areas during mind wandering. Christoff et al. , e.g. ( Christoff et al. 2009 ; Fox et al. 2015 ), have found that episodes of mind wandering recruited not only core areas of the default mode network—medial PFC, posterior cingulate/precuneus, and posterior temporoparietal cortex—but also dorsal anterior cingulate cortex and dorsolateral prefrontal cortex, “the 2 main regions of the executive network” ( Christoff et al. 2009 , 8722). Christoff et al. plausibly link the involvement of the executive network with task performance decrements. The cognitive control proposal adds the possibility that executive network recruitment is associated with the goal-directed nature of (at least some) unintentional mind wandering.

Consider, further, recent work on the dynamics of mind wandering. In a recent review, Christoff et al. (2016) rightly notice that much research on mind wandering has been content-based, “assessing the contents of thoughts in terms of their relationship to an ongoing task or activity” (722). They seek, instead, to offer a taxonomy of thought-types in terms of their dynamics—of how they operate over time. They propose two dimensions along which the dynamics of thought may be influenced. The first dimension is characterized in terms of the degree to which thought is constrained by mechanisms that are “flexible, deliberate, and implemented through cognitive control” (719). The paradigm here is the intentional generation of a deliberative process, or the intentional maintenance of attention on a task. The second dimension is characterized in terms of the degree to which thought is constrained by mechanisms that are automatic, in that they “operate outside of cognitive control to hold attention on a restricted set of information” (719). There are many ways thought may be automatically distracted—Christoff et al. mention affectively salient stimuli as one example.

Within our framework, mind-wandering can be defined as a special case of spontaneous thought that tends to be more-deliberately constrained than dreaming, but less-deliberately constrained than creative thinking and goal-directed thought. In addition, mind-wandering can be clearly distinguished from rumination and other types of thought that are marked by a high degree of automatic constraints, such as obsessive thought. (719)

Now, this is not an explanation of why the mind wanders. It is, instead, a mapping of mind wandering onto a broader taxonomy of cognitive kinds, with special attention given to other modes of spontaneous thought. This taxonomy is useful for a number of reasons. For example, Christoff et al. map their taxonomy onto areas of the brain. So they say, e.g., that the part of the default network that centers on the medial temporal lobe is likely to be involved in the generation of mind wandering, as well as, via “its involvement in contextual associative processing” (724), the conceptual variability of some episodes of mind wandering. They also link the hippocampus to mind wandering, suggesting that it may contribute to the “imaginative construction” of hypothetical scenarios. Such mapping work from aspects of spontaneous thought onto activity patterns in large-scale brain networks affords fruitful suggestions for future study of the kinds of psychological patterns and activities that characterize mind wandering over time.

But there are possibilities and explanations that this approach does not (yet) address, and that potentially have consequences for the taxonomy of cognitive kinds that they offer.

Creative thinking may be unique among other spontaneous-thought processes because it may involve dynamic shifts between the two ends of the spectrum of constraints. The creative process tends to alternate between the generation of new ideas, which would be highly spontaneous, and the critical evaluation of these ideas, which could be as constrained as goal-directed thought in terms of deliberate constraints and is likely to be associated with a higher degree of automatic constraints than goal-directed thought because creative individuals frequently use their emotional and visceral reactions (colloquially often referred to as “gut” reactions) while evaluating their own creative ideas. (Box 1, 720)

I suggest that mind wandering is similarly complex. If the cognitive control proposal is correct, then in at least some cases mind wandering is initiated by processes of cognitive control, even though the goal driving mind wandering is not set explicitly by the agent. This could be captured by adding layers onto Christoff et al. ’s taxonomy, deepening explanations of the etiology and function of each kind of spontaneous thought. And these deeper explanations at each place could be expected to bear fruit for understanding the dynamics of spontaneous thought. In particular, we might hope to find patterns in the neural dynamics that are predictive of the onset as well as the termination of mind wandering episodes, and that differentiate it from dreaming, creative thought, and perhaps from rumination. If the cognitive control proposal is correct, one task would be to map these patterns onto the expected value calculations the cognitive control system is performing. We would expect the dynamics of mind wandering to reflect the initiation of a search for a more rewarding goal, and to reflect attempts to make progress on this search. But now I’m jumping ahead, to predictions the proposal generates.

The cognitive control proposal makes predictions. Confirmation of these would be good news; disconfirmation would be bad news.

First, given the explanation offered for the initiation of mind wandering episodes, the proposal predicts that increases in reward for satisfying an occurrent goal would correlate with decreases in propensity to mind wander. It is well-confirmed that increasing reward leads to boosts in performance level, and to overcoming any purported “ego-depletion,” even for very boring tasks. Paradigms that have established this result could be used to test for the place of mind wandering in the behavioral data.

Second, the proposal predicts that increases in reward for non-occurrent goals the agent possesses would increase mind wandering. We have already seen that reminding agents of goals they possess, or of goals they will soon need to attempt to satisfy, leads to more mind wandering in the direction of these goals. The prediction here is more specific. If one were to, e.g., notify participants that they were soon to perform a task associated with some level of reward, and then to put participants through a low reward task, the prediction is that tendency to mind wander towards this task would be associated with the discrepancy in reward between the current and upcoming task.

Third, this proposal draws upon a view of the cognitive control system on which the learning of values associated with goals, and the learning of values associated with stimuli features predictive of goals, is crucial. So the proposal, plus plausible assumptions about reinforcement learning processes, predicts that it is possible to train participants to associate stimuli with certain goals, and that registration of such stimuli would generate mind wandering to the degree that the associated goal is rewarding. Very costly goals would produce little mind wandering. Cheap but rewarding goals would produce more.

And it may be possible to extend this result. It depends on what the agent associates with rewarding goals. Above I suggested that the system need not always compare value between explicit goals, and that the value computation might include an association between expected levels of reward and particular environments. If so, simply placing an agent in such environments would manipulate levels of unintentional mind wandering.

It may be useful to distinguish predictions this proposal makes from a related proposal: the current concerns hypothesis. The current concerns hypothesis (for which, see Klinger et al. 1973 ; Smallwood and Schooler 2006 ) has it that mind wandering is caused by a shift in salience—when one’s current goals (or concerns: here I use these terms interchangeably), become more salient than the external environment, one’s mind begins to wander. As Smallwood explains the view, “attention will be most likely to shift to self-generated material when such information offers larger incentive value than does the information in the external environment” (2013, 524). This proposal is distinct from mine in the following ways. First, I propose a specific mechanism, connected with recent modeling work in cognitive control, to explain the onset of mind wandering. Thus far, of course, the proposal can be seen as a specification of the current concerns hypothesis. Second, this mechanism initiates mind wandering not by turning attention to one’s current concerns, but by directed thought to search for a more valuable goal than the present one. So the cognitive control proposal makes predictions the current concerns hypothesis does not. For example, the cognitive control proposal predicts that propensity to mind wander could be increased by devaluing the present goal, independently of the salience of any of one’s current goals. That is, no matter how much one’s current goals or concerns lack salience, once could increase mind wandering by devaluing the occurrent goal. And it predicts that mind wandering will not turn directly to one’s other goals—the mind may wander to the environment, rather than to internal concerns, since this is one way the agent may attempt to find a more rewarding task. So we should, e.g., be able to find episodes of more intense environmental scanning as a part of the mind wandering episode. Indeed, if the environment is expected to contain valuable options, one would predict that this is where attention will go, rather than to any internal space of concerns.

This is not to deny that mind wandering represents a failure in some sense. McVay and Kane (2010b ) have argued that mind wandering represents an executive control failure. What fails is a process of goal maintenance: “we suggest that goal maintenance is often hijacked by task-unrelated thought (TUT), resulting in both the subjective experience of mind wandering and habit-based errors” (324). The possibility I am raising is that failures of goal-maintenance could in another sense be successes of a different process. Indeed, perhaps processes of goal-maintenance are closely related to the value-based process of estimating the expected value of continuing on some task, or of searching for a new task, that I propose underlies unintentional mind wandering.

In sum, the proposal is plausible on its face. If correct, it promises to explain a range of data regarding mind wandering, and to explain the—from the agent’s conscious perspective very puzzling—initiation of mind wandering episodes. The proposal may also contribute to explanations of the dynamics of mind wandering. The predictions this proposal makes are testable, and work in this direction might take steps towards further integrating knowledge of how cognitive control works with knowledge of how mind wandering works.

I wish finally to relate this proposal to two leading philosophical accounts of mind wandering. Both of these accounts aim to capture mind wandering quite generally. I have noted in Mind wandering section that this is not my aim. Here, I want only to discuss implications for these more general accounts of mind wandering, if the cognitive control proposal about unintentional mind wandering is on track.

[T]he ability to control the conscious contents of one’s mind in a goal-directed way, by means of attentional or cognitive agency. This ability can be a form of rational self-control, which is based on reasons, beliefs, and conceptual thought, but it does not have to be. What is crucial is the “veto component”: Being mentally autonomous means that all currently ongoing processes can in principle be suspended or terminated. This does not mean that they actually are terminated, it just means that the ability, the functional potential, is given and that the person has knowledge of this fact. M-autonomy is the capacity for causal self-determination on the mental level. (2013, 4)

I think the brush strokes Metzinger uses are too broad. I doubt we have veto control over every conscious process ongoing at a time. But I do think he locates an interesting phenomenon. In unintentional mind wandering, our knowledge (or awareness) that we might suspend, terminate, or re-direct aspects of the stream of consciousness lapses.

My question is this. Should we think of this lapse as the agent’s loss of control? As Metzinger has it, mind wandering essentially involves a lack of ability, and a lack of control—what he calls veto control. I agree that unintentional mind wandering does involve a loss of one kind of control. But I would underline the fact that there are multiple ways for a system to exercise control. Some of these involve consciousness in crucial ways. Some likely do not ( Shepherd 2015 ). Knowledge that one can exercise control in some way at a moment can be useful. But a system may be well-designed, and exercise control in finding or executing goals, even if the system is not explicitly aware of processes that are performing these functions at a time.

Further, there are multiple ways for a system or an agent to possess an ability. The mind wandering agent may lack the ability to suspend, terminate, or re-direct elements of the stream of consciousness in virtue of her knowledge or awareness that she can do so. But she may retain the ability to suspend, terminate, or re-direct elements of the stream of consciousness in virtue of other features—perhaps in virtue of signals that emanate from the cognitive control processes I have emphasized.

This is not a merely verbal distinction. It is about how we understand the constitution of agency, and the kinds of properties that should be ascribed to mind wandering. If the cognitive control proposal is right, mind wandering emerges as an interesting case in which the seams of agency pull apart somewhat—we fail to notice that a non-conscious mechanism has turned the stream of consciousness in a different direction. But there may be good functional reasons for this operation, and it may contribute to an agent’s overall capacities to control the self in various environments and contexts.

An agent A’s attention is unguided if and only if A is not habitually guided to focus her attention on any information. In particular, she does not satisfy the counter-factual condition for attentional guidance: There is no information i such that, if A’s attention isn’t focused on i, she will notice, feel discomfited by, and thereby be disposed to correct this fact. (567)

I am not sure this is right. Mind wandering episodes are sometimes short. Sometimes they stop, it seems to me, precisely because we feel a sense that we were recently up to something, and we feel a pull to return. The cognitive control proposal might be able to explain this—one good move for the cognitive control system, in case of a failure to find a more rewarding task or goal, would be to return to the previous task.

Irving is aware that when it wanders, the mind frequently circles back to the agent’s goals. Does this not suggest guidance of some sort? Irving explains the tension by distinguishing between guidance and motivation. Motivated behavior only requires that an agent’s beliefs, desires, or goals are causal antecedents of the behavior. Guided behavior, by contrast, is explicated in terms of dynamics: it “involves the online monitoring and regulation of behavior” (563). Irving claims that mind wandering may be motivated, but it is not guided.

This aspect of Irving’s account does not compare favorably with the cognitive control proposal—if, of course, future work confirms the proposal. For Irving’s account offers no explanation of how causation by some belief or desire or goal helps explain how or why the wandering mind frequently turns to the agent’s goals. The cognitive control proposal has it that the wandering mind finds goals because that aim is what initiated and governs the mind wandering episode.

Further, if my proposal is right it is not entirely correct to think of mind wandering as unguided. It is, admittedly, not guided by any explicit intention the agent forms. In one sense of “guided,” then, Irving is right. But on the cognitive control proposal, mind wandering is a cognitive control process, and it does have a purpose. It seems purposeless to us in part because it is an interesting case in which some of the seams of agency pull apart somewhat—we do not notice that a non-conscious mechanism has turned the stream of consciousness in a different direction. And it seems purposeless to us in part because the course of the stream of consciousness during mind wandering is, as the cognitive control system plans it, meandering. It is meandering because the goal is to search, to explore, until a more rewarding task is found.

If these considerations are on track, we should say that mind wandering takes the form of a conscious but non-consciously guided process the aim of which is to find a rewarding goal or task. The connection with the cognitive control system explains the guidance aspect—the functionality of mind wandering—and affords the possibility of integration with work on the dynamics of mind wandering. The non-conscious aspect of the guidance explains the air of mystery surrounding mind wandering, why it seems purposeless, and why it seems to come about randomly.

In this article, I have asked why the mind wanders. I focused on a sub-type of mind wandering—mind wandering that occurs independently of any reportable intention. I proposed that unintentional mind wandering is sometimes initiated and sustained by aspects of cognitive control. Unintentional mind wandering is caused by the cognitive control system precisely when, and because, the expected value of whatever the agent is doing—usually, exercising control towards achievement of some occurrent goal—is deemed too low, and this “too low” judgment generates a search for a better goal, or task.

This proposal generates testable predictions, and suggests open possibilities regarding the kinds of computations that may underlie unintentional mind wandering. My hope is that by connecting research on mind wandering with research on cognitive control resource allocation, fruitful strategies for modeling these computations may be taken from cognitive control research and deployed to help explain the initiation and dynamics of mind wandering episodes.

The cognitive control proposal also points us towards a fuller picture of human agency. In this picture, action control and intelligent thought are stitched together by conscious and non-conscious processes operating in concert. Future empirical work is critical to the confirmation of this picture, and to filling in the many unspecified details. This is so not least because, if the proposal I offer is on track, agents are not introspectively aware of the (good) rationale behind many mind-wandering episodes.

The author acknowledges two sources of support. First, funds from European Research Council Starting Grant 757698, awarded under the Horizon 2020 Programme for Research and Innovation. Second, the Canadian Institute for Advanced Research’s Azrieli Global Scholar programme on Mind, Brain, and Consciousness.

Conflict of interest statement . None declared.

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When Your Mind Wanders

A new review article discusses the mysteries of mind-wandering.

Posted June 8, 2015

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How often does your mind wander in an average day? Be honest.

It's certainly something that we all do, especially when we're bored or tired. Also known as "task-unrelated thought," mind wandering involves the decoupling of our thoughts from whatever we happen to be doing at the time. Though usually harmless, mind wandering can become potentially lethal if it causes us to stop paying attention at a critical moment, such as when we are driving or operating heavy machinery. Pierre Curie, husband of Marie, was killed in a street accident when he was struck by a horse-drawn cart. Family members later speculated that he hadn't been watching for traffic because of his mind wandering, a frequent problem for the brilliant scientist. Not surprisingly, mind wandering has been shown by researchers to be linked to automobile accidents and general road safety .

But why do our minds wander? And what do we think about when we are unable to concentrate on what we are doing? Research into mind wandering suggests that it isn't quite the time waster that people often believe it to be. In fact, some researchers suggest that mind wandering may have evolved as a way of helping us handle monotonous tasks more effectively.

Even what we think about while our minds are wandering may be important. For example, studies of mind wandering show that people are more likely to think about the future than the past or present. We are also more likely to dwell on personal issues, including trying to solve difficult problems we have. Perhaps more importantly, mind wandering is a way of shutting out the world. Despite being potentially dangerous when done at the wrong time, mind wandering likely allows us to use our higher cognitive abilities for more productive things. This means that it may be essential to our ability to solve problems and stay creative.

A new review article published in the Canadian Journal of Experimental Psychology explores the cognitive neuroscience behind mind wandering. Written by Todd Handy and Julia Kam from the University of British Columbia, the article reviews a series of recent studies and shows some of the implications of mind wandering and what it means to be human.

While it is often difficult to measure mind wandering in research studies, one method that seems extremely effective is known as experience sampling . Basically, this involves interrupting research subjects at random intervals whenever they are working on a given task and asking them to report on their mental experiences at that specific moment. With experience sampling, researchers can then determine how often mind wandering occurs and under what circumstances. By using experience sampling in conjunction with EEG and event related potential research, mind wandering has also been linked with specific brain states.

For example, one research study found that the P300 wave linked to decision making can be used to predict selective attention and mind wandering during monotonous tasks. Specific brain regions such as the extrastriate visual cortex and the primary auditory cortex show reduced activity during mind wandering states reflecting the reduced attention of external sights and sounds. In other words, people who are mind wandering literally become less aware of the world around them.

Still, while this attention to outside stimuli is reduced, it never completely goes away. Abrupt changes, such as someone honking at you while you are stopped at a light which has changed from red to green, will cause you to snap back to reality and become aware of what you are doing. Research studies looking at tracking errors during tasks such as following a moving dot on a computer screen showed that errors were especially high whenever people were mind wandering. Also, mind wandering affects our very ability to monitor how well we are doing in different tasks, and it doesn't seem to matter whether the task is monotonous or not. Even when we are doing something potentially dangerous (such as driving) in which the consequences of not paying proper attention could be life-threatening, mind wandering can still occur.

So why aren't the consequences of mind wandering more serious? Even when we are driving or walking and our minds begin to wander, our ability to function "on automatic" can often prevent any mishaps despite the fact that we aren't really paying attention to what we are doing. Research looking at how mind wandering affects different executive functions , including response inhibition and working memory , suggests that they are often absent when our mind wanders and we begin thinking of other things beside the task at hand. What saves us though is our capacity for mental set-shifting or cognitive flexibility . This is the ability to switch between thinking about different concepts at the same time (i.e., our ability to "multi-task"). Being able to snap back to attention instantly to whatever we are presently doing is a critical part of dealing with mind-wandering, not to mention avoiding the mishaps that can occur when we are not paying attention to something important.

Cognitive flexibility seems especially important in detecting deviant events despite our mind-wandering. If we glance back and see that everything is normal, we likely don't give it a second thought and continue with our mind wandering. If we detect that something is wrong however (such as a car suddenly cutting in front of ours), then our attention snaps back and we are able to devote our full attention to what we are doing (along with a lot of honking and swearing).

Based on these different research findings, Todd Handy and Julia Kam suggest that selective attention plays a key role in mind wandering. It is already well-established that selective attention acts as a "gatekeeper" to help us control the different sensory impressions we receive all the time (thus our ability to shut out unwanted noise or other things that might distract us). How often are you aware of the sensation of sitting in that chair or the clothes that you are wearing? Since we don't need to be aware of everything at once, selective attention allows us to establish priorities so we can stay aware of the world around us even when we are mind-wandering.

Learning more about the role that selective attention plays in mind-wandering can also be important in understanding conditions such as attention-deficit hyperactivity disorder and major depression in which people find themselves unable to concentrate for long on what they are doing. For that matter, our minds tend to wander less as we grow older, possibly because of changes in executive functioning as we age.

As we discover more about the inner workings of the human brain, mysteries such as mind-wandering may become easier to explain. So next time you find yourself drifting off when you really should be doing something else, try to appreciate the complex brain mechanisms that make it so easy for you to shift back and forth. A wandering mind is a terrible thing to waste.

Romeo Vitelli, Ph.D. is a psychologist in private practice in Toronto, Canada.

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Spontaneous cognition (mind-wandering): How random thoughts and daydreams emerge from the brain

Aditya Shukla  |  May 27, 2022 June 4, 2020  |  Disclaimer: Links to some products earn us a commission

Home » Attention » Spontaneous cognition (mind-wandering): How random thoughts and daydreams emerge from the brain

Why do random thoughts pop into the mind? Why does the mind wander? Why do we daydream? Why do we get random creative or depressive thoughts? Why did I just remember to close the door in the middle of the movie? The answers lie in what scientists call spontaneous cognition and mind-wandering that comes with a fired-up brain network called the default mode network.

Most of us notice random spontaneous thoughts that pop into our minds once we have them. They are often out of context. These are the spontaneous involuntary memory traces and racing thoughts/fantasies that emerge into our awareness when the mind is idle. A lot of overthinking comes from spontaneous cognition.

What are spontaneous cognitions?

Why does our mind wander, mind-wandering vs. negative automatic thoughts, spontaneous cognition vs. obsessive thoughts, mind-wandering vs. daydreaming, what are the types of spontaneous cognitions, default mode network theory of spontaneous cognition.

Definition : Spontaneous cognition is defined as involuntary self-generated internal mentation that occurs when our mind wanders and withdraws from the external world.

Let’s break it down. Involuntary refers to our lack of control over when they occur. Self-generated implies you create them on your own. Internal refers to spontaneous cognitions being a phenomenon that occurs within one’s mind with no external component. Mentation is a fancy word for mental activity. Mind-wandering is a general term that describes a brain state which is not purposefully directed toward external information/stimuli. It the brain’s passive resting state and the idle mind roams around freely accessing random memory units creating hypotheticals, simulations, internal verbal dialogs. We usually do not know why a spontaneous cognition occurs; sometimes, it is indirectly influenced by triggers or cues . Some spontaneous thoughts are good (creative insights), some are neutral (random memories) and some are negative (random depressive thoughts). While not truly random, the probability of a particular type of spontaneous thought can go up or down based on other factors like mental status, recent activities, obsessions, etc. These probabilities may change over time. (see types of spontaneous cognitions below)

Researchers often study “Task unrelated thoughts” and “day-dreaming” as a substitute for spontaneous thoughts because they have similarities such as both are unrelated to the work one does while having them.

Klinger (1971) [1] suggests that mind-wandering primarily consists of thoughts important to the self. Recent research [2] provides evidence that spontaneous cognitions are often matters of self-importance such as goal-oriented thoughts about the past and future. Spontaneous cognitions can manifest as mental imagery of all senses as well as vocal internal dialog.

What is mind-wandering?

When people zone out, their mind is most likely wandering with an inward focus while staying detached from the outside world.

Definition: Mind-wandering is a global mental state that generates internally driven thoughts that move in no particular direction. This state of mind preferentially exists in the absence of external stimuli and goals and we usually experience a loss of autonomy in retrospect. That is, when you are superficially disconnected from the external world or idle, your mind goes into an unpredictable free-floating state before you realize it.

It is the capacity to retreat and decouple from our immediate environment. Researcher Thomas Metzinger [3] says that mind-wandering is characterized by a loss in our attentiveness and cognitive control. That means, in a mind-wandering state, you have little to no deliberate control over attention on any kind of information and little to no deliberate generation of thoughts or goal-directed ideas.

Mind-wandering is best explained in the context of the brain’s default mode network: a network of brain regions that is robustly active in the absence of attention toward a specific thing. When the mind is idle, the default mode network shows high activity; when it is hyper-engaged, it has low activity. The network is largely suppressed when we are fully engaged in a task that needs our attention. A drop in mental effort, suppression of incoming information, and small triggers can put us in a self-sustained mind-wandering state. The more our mind wanders, the more active the default mode network is. That creates a bubbling opportunity for spontaneous cognitions to emerge from. Spontaneous thoughts are seemingly random because the memories that build the thoughts are accessed by the brain’s default mode network in ways we can’t predict and some of them from the possible millions pop into awareness.

Mind-wandering is often the larger context in which we experience specific spontaneous thoughts like rumination, creative insights, and musical earworms. Mind-wandering has a high variety of thoughts with no direction but some spontaneous cognitions are specific. According to researchers [4] , mind-wandering or spontaneous cognitions are relatively free, fluid, poorly constrained thoughts or sequences of thoughts that belong to a larger family of spontaneous phenomena which includes dreaming and creative thinking. However, mind-wandering is by definition a mental state that occurs when one is awake.

Trivia : A study [5] suggests that those who have higher mind-wandering tend to switch between tasks faster. The ability to switch between tasks is called cognitive flexibility which may be essential in certain types of jobs or tasks.

Difference between Negative Automatic Thoughts, Obsessions, Daydreaming and Spontaneous Cognition

Mind-wandering/Spontaneous thoughts differ from negative automatic thoughts but negative automatic thoughts may be the offsprings of spontaneous cognition. Negative automatic thoughts are usually a symptom or manifestation of depression and anxiety. They are negatively framed thoughts about the self, future, or the world in general. They include judgments about oneself and often continue in a feedback loop (one generates/modifies another) or cycle. But spontaneous cognitions do not occur as a chain of thoughts in a closed feedback loop or discernable pattern.

Spontaneous cognitions are different from obsessive thoughts as well although one can obsess over a spontaneous cognition that occurs during mind-wandering or routine habitual work. Obsessive thoughts typically get a disproportionate and inappropriate quantity of attention. For example, people with obsessive-compulsive disorder can have an unnatural preoccupation with a type of spontaneously emerging thought that causes anxiety and triggers a ritualistic behavior to reduce that anxiety. Such as, OCD with musical earworms: obsessing on musical earworms, which are theorized as spontaneous cognitions, become the object of obsession with a compulsive need and behavior to deal with it.

Why do we daydream? The best answer we have is that the brain, in its idle state, is disconnected from the outside world and generates its own stream of conscious thoughts. In this state, our attention is unguided and focused inward. It explores the mind as a private story with social elements, random mental images as well as future and past hypothetical ideas/fantasies. This mechanism is supported by the default mode network. Some daydreaming can be fun and enjoyable but some of it interferes with our productivity.

So is mind-wandering the same as daydreaming? In a way. Mind-wandering and daydreaming are similar processes. Both involve jumping into an inner fantasy world by losing attention to the outside world. The difference is a matter of degree, not kind. Daydreaming can be highly dissociated from reality [6] whereas mind-wandering can be grounded in relevant reality. However, daydreaming [7] , like obsessions and negative automatic thoughts, has a more clinical application because day-dreaming can be maladaptive in some patients and even in old-age. Daydreaming is a long stream of consciousness that feels like a fantastical story where a person is lost in imagination. Some people daydream up to 4 hours a day and it can be a sign of mental health disturbances [8] .

Here are some examples of spontaneous thoughts and involuntary memories that pop into the mind.

1. Rumination: Rumination or depressive rumination is the tendency of a person to disconnect from the world and engage in racing repetitive negative thoughts. They often have themes like loneliness, fantasy relationships, interpersonal conflict, negative self-evaluation, critical judgments about the self, and a sense of threat or apathy from others. Rumination often occurs spontaneously and the default mode network is active during these episodes. Rumination is sometimes a clear indicator of depression and anxiety. Researchers consider [9] this to be a specific category of spontaneous cognition which is not truly mind-wandering. Here is one way to stop rumination and those random negative/depressing/anxious thoughts that creep into the mind.

2. Biases: Spontaneous thoughts are colored with biases that may emerge from a person’s mental health status such as depression. In one study [10] , researchers found that people with dysphoria (severe depression) experience more future-oriented negative spontaneous thoughts/imagery and fewer positive spontaneous thoughts/imagery as the level of depression rises. This mimics a similar trend in deliberate thoughts: higher depression is linked to higher negative thoughts and fewer positive thoughts.

3. Future and past thinking: Thoughts that occur when people zone out with a mind-wandering state are often related to the past or the future, sometimes called spontaneous episodic thoughts or involuntary memories. Based on a study [11] that measured “ involuntary autobiographical memories ” as an indicator of mind-wandering, people with depression are likely to have unprompted abstract hypothetical future thoughts but the less depressed or healthy individuals are likely to have goal-oriented future thoughts that involve planning. The same study also suggests that people, in general, are likely to have spontaneous thoughts about existing past memories than future thoughts. One small study [12] found that older people have a lower frequency of self-generated thoughts, spontaneous cognition, and future-thinking than younger people.

4. Musical Earworms: Songs that randomly emerge and stick in the mind are a type of auditory spontaneous cognitions called “involuntary musical imagery”. Mind-wandering means large unpredictable fluctuations in brain activity and seemingly random access to units of memory. Some of those are memories of musical sequences.  Spontaneous cognitions [13]  like musical earworms often pop into our awareness when the mind is idle, probably because of reactivated memory systems and fluctuations in attention associated with the default mode network. Unlike other examples here, musical earworms stick around because of their incomplete/unresolved nature and the ironic-process: Just being aware of the music makes the brain highlight it even more.

5. Creative cognition: Boden (2004) defines creativity as “the ability to come up with ideas or artifacts that are new, surprising, and valuable” With this definition in mind, mind-wandering (as we’ll see later) and spontaneous cognition can be a breeding ground for unexpected creative insights. Creative cognition involves traversing through large domains of information to make new connections . Mind-wandering supports those underlying processes. It is also linked to a more “ abstract ” form of thinking. Unlike rumination and negatively biased future thoughts, creative cognition is flexible [14] . Cognitive components that are randomly activated through the default mode network’s high activity (next section) are sometimes intimately entangled with each other. That entangling makes “creative” cognition as well as enhanced learning possible. It also partly explains why some active procrastinators show more creativity .

Spontaneous cognition can also be described based on how they occur. This approach gives us two types of spontaneous cognition.

Stimulus-independent: A spontaneous thought that occurs without the direct influence of an external stimuli. Musical earworms and spontaneous planning are instances of these.

Stimulus-dependent: A spontaneous thought that occurs as a response to a cue or trailing piece of information. One application [15] of measuring these is the early detection of Alzheimer’s disease as stimulus-dependent cognitions can be a good marker of mild cognitive impairment.

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Most lines of evidence highlight the default mode network’s role in spontaneous cognition. The default mode network [16] shows heightened activity when our attention and focus on the external world is significantly reduced. As mental work reduces ( low cognitive load ), the likelihood of spontaneous mental images and dialogs increases. The brain regions involved are medial temporal lobe subsystem, medial prefrontal cortex, posterior cingulate cortex, angular gyrus, and ventral precuneus. These govern internal dialog, self-referential memory, emotional valence, memory details, stimulus-independent perception, etc. This network may help us explore and monitor our inner world. It’s best imagined as a deep-access all hands on deck type of meeting that has millions of interactions across the brain’s cortical regions.

Some evidence [17] shows that the default mode network plays a large role in retrieving autobiographical memories (memory about experiences) and self-referential thoughts – both key aspects of spontaneous cognition. Over the decades, research on the default mode network suggests 2 apparently contradicting reasons why the network is fired-up. But both reasons have the same end-goal of processing what we know and preparing us for the future :

• Mental exploration and preparation: Freely moving internally generated thoughts, devoid of attention to the outside world, create extensive access to memories and hypothetical situations that prepare us for upcoming stimuli.
• External monitoring and orientation: Broad but weak attention states like watchfulness and peripheral vigilance (background alertness) prepare us to deal with future or imminent experiences. That is, enhance watchful awareness for upcoming stimuli.

Neurobiological research [18] on the default mode network shows it is highly sensitive to spontaneous cognition and most probably facilitates the occurrence of spontaneous cognition regardless of attention to the external world. It may be an evolutionary advantage for human brains to assess, monitor, generate, and identify internal thoughts because it helps us prepare for new experiences. That is, it manifests as a function of “ mental exploration and preparation “. However, both are likely to be true on different levels as the jury is still out on the limits of both functions of the default mode network. Creative thoughts often depend on the combination of unlikely memories and bits of information that the default mode network might facilitate through its broad access to brain areas where memory is spread out.

Benefits of an active default mode network:

• It helps us explore our mind
• It helps us generate creative insights
• It offers an escape into a fantasy world (daydreaming)
• It indicates faster attention-switching or cognitive flexibility

The downside of an active default mode network:

• Excess activity implies high mind-wandering which may lead to a chain of negative thoughts (rumination)
• High frequency of similar thoughts can be distressing
• The mind’s connection with the outside world is temporarily lost

How much mind-wandering is conscious or subconscious?

There are 2 core assumptions about the relationship between the default mode network and us recognizing that we had a spontaneous cognition.

• Most processes don’t reach our awareness and only some that reach become “spontaneous cognitions.”
• Of the possible millions of micro-processes that occur when the default mode is active, only some configuration of processes generate thoughts and they became what we call “spontaneous thoughts.”

In summary, there is evidence to show that the default mode network is activated when we zone out, day-dream, detach from the external world, or go into the mind-wandering zone which enables most types of spontaneous cognition such as creative cognition, musical earworms, rumination, and involuntary autobiographical memory .

P.S. Thumbnail Photo by  Frank Cone [19]  from  Pexels [20]

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It’s long been associated with failing grades and accidents behind the wheel, but it turns out that the wandering mind may be far more complex than many believe.

A new article by Paul Seli, a postdoctoral fellow working in the lab of Dan Schacter , the William R. Kenan Jr. Professor of Psychology, examines variations in mind wandering. In the article, Seli and colleagues argue that mind wandering happens both with and without intention, noting important differences between the two in terms of causes and consequences. The research pointing to this conclusion is outlined in a paper in Trends in Cognitive Sciences .

Researchers first began examining mind wandering — or “task-unrelated images and thoughts” — in the late 1970s. Despite a noted difference between intentional and unintentional modes, the distinction had little impact on the field and consequently fell by the wayside.

“Over the years, a number of different constructs have been unified under the single term ‘mind wandering,’ and through that process, the distinction between intentional and unintentional types was lost,” said Seli. “However, if intentional and unintentional types of mind wandering behave differently, and if their causes differ, then it would be exceptionally important to distinguish between the two. Without such a distinction, researchers will effectively conflate two unique cognitive experiences, and as a consequence, our understanding of mind wandering will be incomplete and perhaps even flawed.”

By the time Seli, as a Ph.D. student at the University of Waterloo in Canada, began to look into mind wandering, it was largely regarded as unintentional thought with links to a range of negative consequences.

Before long, though, he began to suspect something deeper was at work.

“To study mind wandering in the lab, we often present participants with boring tasks to elicit these task-unrelated thoughts,” he said. “Throughout these tasks, we typically assess mind wandering by presenting participants with ‘thought probes,’ which are temporary task interruptions that require them to report whether their thoughts are focused on the task or on something unrelated.”

Online learning: It’s different

Over the course of several experiments, Seli began to realize that some participants weren’t simply losing their focus, but seemed to intentionally disengage.

“In some cases, the participants clearly didn’t care about the task whatsoever … they were simply there for the $10 or for course credit,” he said. “So when these participants experienced mind wandering, it was likely the case that this mind wandering was initiated intentionally, rather than unintentionally.

“Now, there are certainly instances where people care about performing well on these laboratory tasks, and despite their best intentions to stay focused, their thoughts drift away, but it became clear to me that this isn’t always true, even though this is often the assumption that is made in the literature. If people do in fact frequently experience intentional mind wandering, and if the causes of intentional and unintentional mind wandering differ, then this would be exceptionally important because it would suggest that attempts to reduce the occurrence of mind wandering will also likely differ.”

Seli, working first with colleagues in Canada and then at Harvard , set about devising experiments aimed at understanding the distinction between intentional and unintentional mind wandering.

One way to demonstrate that intentional and unintentional mind wandering are distinct experiences, the researchers found, was to examine how these types of mind wandering vary depending on the demands of a task.

In one study, Seli and colleagues had participants complete a sustained-attention task that varied in terms of difficulty. Participants were instructed to press a button each time they saw certain target numbers on a screen (i.e., the digits 1-2 and 4-9) and to withhold responding to a non-target digit (i.e., the digit 3). Half of the participants completed an easy version of this task in which the numbers appeared in sequential order, and the other half completed a difficult version where the numbers appeared in a random order.

“We presented thought probes throughout the tasks to determine whether participants were mind wandering, and more critically, whether any mind wandering they did experience occurred with or without intention,” Seli said. “The idea was that, given that the easy task was sufficiently easy, people should be afforded the opportunity to intentionally disengage from the task in the service of mind wandering, which might allow them to plan future events, problem-solve, and so forth, without having their performance suffer.

“So, what we would expect to observe, and what we did in fact observe, was that participants completing the easy version of the task reported more intentional mind wandering than those completing the difficult version. Not only did this result clearly indicate that a much of the mind wandering occurring in the laboratory is engaged with intention, but it also showed that intentional and unintentional mind wandering appear to behave differently, and that their causes likely differ.”

The findings add to past research raising questions on whether mind wandering might in some cases be beneficial.

“Taking the view that mind wandering is always bad, I think, is inappropriate,” Seli said. “I think it really comes down the context that one is in. For example, if an individual finds herself in a context in which she can afford to mind-wander without incurring performance costs — for example, if she is completing a really easy task that requires little in the way of attention — then it would seem that mind wandering in such a context would actually be quite beneficial as doing so would allow the individual to entertain other, potentially important, thoughts while concurrently performing well on her more focal task.

“Also, there is research showing that taking breaks during demanding tasks can actually improve task performance, so there remains the possibility that it might be beneficial for people to intermittently deliberately disengage from their tasks, mind-wander for a bit, and then return to the task with a feeling of cognitive rejuvenation.”

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What Does "Mind-Wandering" Mean to the Folk? An Empirical Investigation

Affiliations.

• 1 Corcoran Department of Philosophy, University of Virginia.
• 2 Department of Psychology, University of California, Berkeley.
• 3 Departments of Psychiatry and Philosophy, University of Michigan.
• PMID: 33037714
• DOI: 10.1111/cogs.12908

Although mind-wandering research is rapidly progressing, stark disagreements are emerging about what the term "mind-wandering" means. Four prominent views define mind-wandering as (a) task-unrelated thought, (b) stimulus-independent thought, (c) unintentional thought, or (d) dynamically unguided thought. Although theorists claim to capture the ordinary understanding of mind-wandering, no systematic studies have assessed these claims. Two large factorial studies present participants (N = 545) with vignettes that describe someone's thoughts and ask whether her mind was wandering, while systematically manipulating features relevant to the four major accounts of mind-wandering. Dynamics explains between four and 40 times more variance in participants' mind-wandering judgments than other features. Our third study (N = 153) tests and supports a unique prediction of the dynamic framework-obsessive rumination contrasts with mind-wandering. Our final study (N = 277) used vignettes that resemble mind-wandering experiments. Dynamics had significant and large effects, while task-unrelatedness was nonsignificant. These results strongly suggest that the central feature of mind-wandering is its dynamics.

Keywords: Conceptual analysis; Daydreaming; Experimental philosophy; Folk psychology; Mind-wandering; Spontaneous thought; Task-unrelated thought.

© 2020 Cognitive Science Society, Inc.

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The brain on silent: mind wandering, mindful awareness, and states of mental tranquility

David r. vago.

1 Functional Neuroimaging Laboratory, Brigham & Women's Hospital and Department of Psychiatry, Harvard Medical School, Boston, Massachusetts

Fadel Zeidan

2 Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Winston-Salem, North Carolina

Mind wandering and mindfulness are often described as divergent mental states with opposing effects on cognitive performance and mental health. Spontaneous mind wandering is typically associated with self-reflective states that contribute to negative processing of the past, worrying/fantasizing about the future, and disruption of primary task performance. On the other hand, mindful awareness is frequently described as a focus on present sensory input without cognitive elaboration or emotional reactivity, and is associated with improved task performance and decreased stress-related symptomology. Unfortunately, such distinctions fail to acknowledge similarities and interactions between the two states. Instead of an inverse relationship between mindfulness and mind wandering, a more nuanced characterization of mindfulness may involve skillful toggling back and forth between conceptual and nonconceptual processes and networks supporting each state, to meet the contextually specified demands of the situation. In this article, we present a theoretical analysis and plausible neurocognitive framework of the restful mind, in which we attempt to clarify potentially adaptive contributions of both mind wandering and mindful awareness through the lens of the extant neurocognitive literature on intrinsic network activity, meditation, and emerging descriptions of stillness and nonduality. A neurophenomenological approach to probing modality-specific forms of concentration and nonconceptual awareness is presented that may improve our understanding of the resting state. Implications for future research are discussed.

At the still point of the turning world. Neither flesh nor fleshless; Neither from nor towards; at the still point, there the dance is, But neither arrest nor movement. –T.S. Eliot a

Introduction

What are the phenomenological characteristics of a restful mind? With eyes closed, removed from external distraction, a state of wakeful relaxation may easily be cultivated. Yet, left to its musings, it is common for the mind to experience a relentless stream of evaluative thoughts, emotions, or feelings without much effort. “Monkey mind” is a metaphor for the mind's natural tendency to be restless— jumping from one thought or feeling to another, as a monkey swings from limb to limb. Given the heavy demand of modern life on cognitive load, managing the onslaught of ongoing sensory and mental events throughout daily life and improving efficiency of mental processing is of high concern. Tranquility and stillness of mind, as described in the Buddhist Nikāyas , b are believed to reflect a natural settling of thoughts and emotions, in which there is stability of attention, sensory clarity, and equanimity of affect and behavior. 1 This state is believed to develop through systematic mental training involving a combination of concentration, nonconceptual observation, and discernment. 2 – 4

Although the majority of research on brain function has focused on task-evoked activity, current research focusing on the task-unrelated resting mind–brain is beginning to reveal the critical importance of this largely ignored part of human life. Since the advent of neurophysiological recording, it has been determined that the brain is never truly resting. Hans Berger first observed that all states of wakefulness and sleep reveal a spectrum of mixed amplitudes and frequencies of electrical activity that does not cease. According to thought-sampling studies during mind wandering, 5 – 7 the content of the restless mind is often incredibly rich and self-relevant, characterized by spontaneous thoughts and emotions concerned with the past and hopes, fears, and fantasies about the future, often including interpersonal feelings, unfulfilled goals, unresolved challenges, and intrusive memories. With respect to cost and benefit, research on the “resting state” is demonstrating how task-unrelated or stimulus-independent thought (SIT) may adaptively organize brain function 8 and how the intrinsic neural activity supporting SIT affects brain metabolism and neuroplasticity. 8 – 11 Although there are certainly benefits to having access to the rich landscape of spontaneous thoughts for the purpose of creative incubation, 7 , 12 problem solving, 6 and goal setting, 13 an inability to focus attention in the face of irrelevant distraction by such thoughts can be problematic. Unfortunately, humans have been shown to experience this intrinsic undercurrent of spontaneous, self-generated thought during ongoing task demands as a form of interference, distraction, or rumination approximately 50% of each waking day. 5 , 14 SIT often interferes with the ability to remain externally vigilant, 15 , 16 remain focused or concentrate on the task at hand, 16 properly encode external information, 17 listen, 18 perform, 16 , 19 or even sleep. 20 In addition to the apparent inefficiency that SIT contributes to daily life, there is now a large literature linking a majority of self-generated thought to negatively valenced content and negative mood states, 21 , 22 future unhappiness, 5 and the maintenance of psychopathology, such as generalized anxiety disorder 23 – 25 or major depressive disorder. 26 , 27 Most recently, there has been interest in exploring how particular forms of mental training that include a state of mindful awareness allow individuals to change the relationship with the resting state and experience the stream of stimulus-independent mental content in an adaptive way. 28 – 30

Mindfulness and mind wandering are often described as two divergent mental states; 31 , 32 yet, both are frequently referenced in the context of mental rest. There is a subtle difference in both awareness and engagement with the flow of mental objects that may determine the adaptive or maladaptive nature by which the mental content influences one's current mood and future behavior ( Fig. 1 ). Currently, there is great interest in better understanding the neural mechanisms that support resting-state dynamics, states of mindful awareness, and their respective contributions to mood and cognition (see Refs. 31 and 32 ). In this article, we examine a more nuanced perspective on particular mental states that reflect “rest,” mental quiet, stimulus independence, and the neurobiological and physiological circuitry supporting the various flavors of what may constitute a “restful mind.” Occasionally, references are made to the historical Buddhist literature for the purpose of exploring an epistemology of mind as it relates to contemporary secular adaptations of the construct mindfulness.

Variations in awareness during meditation and mind-wandering rest. Visual (V), auditory (A), and somatic (S) modalities of experience are depicted. Awareness in the present moment is depicted by the blue band around mental objects arising and passing through time. Width of the band represents the temporal focus of awareness. The more temporally extended awareness is in time, the more mental stickiness and disengagement delays are apparent. Wider bands refer to difficulty disengaging from mental or sensory objects, greater projection into past or future experience, and a resulting smaller aperture. FA meditation focuses on only one mental/physical object in experience (somatic object is depicted here). All modalities of experience enter awareness in OM meditation and mind wandering (MW). Variations in qualities of object orientation (engagement/disengagement), clarity, and aperture in experience are depicted. These three qualities are represented, respectively, by the width of the circles for each mental object, brightness of the fill color, and diameter of the ring of awareness that sits in the present moment of time. Adept meditators are believed to experience higher clarity (phenomenal intensity) in both forms of meditation, whereas MW is believed to represent low clarity or dullness. Low object orientation or engagement represents less mental stickiness and rapid disengagement, leaving available more cognitive resources. Aperture (scope of awareness) is believed to be intentionally narrow for a concentration practice and high for OM practice. In MW, the spotlight of attention is typically narrow and unintentional because of increased engagement with each mental object; resources are subsequently depleted. Adapted, with permission, from Farb et al. 27 and Lutz et al. 124 See Lutz et al. 124 for more extensive descriptions of clarity and aperture, as well as for other potential experiential descriptors relevant to mindfulness.

The (not-so) resting state: mind wandering, evaluation, and self-referential processing

The resting state is commonly referred to as the baseline state of mind in quietly awake individuals and in the context of no particular task. Given its task-negative orientation, the resting state has been used as a functional contrast for most active task-positive conditions in functional neuroimaging studies. 33 , 34 In fact, this state has been used as a control or baseline condition against conditions of interest in an overwhelming number of neuroimaging studies, since such methods were introduced in the early 1980s. 33 The instructions for this passive baseline state are frequently given in some variation of, “let your mind freely wander without thinking of anything in particular,” “relax,” or “stay still and do nothing,” and involve either eyes opened or closed; however, to avoid the occurrence of sleep, many protocols have encouraged the use of open eyes, with (and without) a fixation cross as a visual stimulus on which to rest one's eyes.

Interest in the resting state has mostly reflected the interest in the methodological function by which to probe spontaneous low-frequency (<0.1 Hz) blood oxygen level–dependent (BOLD) fluctuations (LFBF) that demonstrate consistent spatially and temporally coherent connectivity among large-scale functional brain networks. 35 – 38 Across each of the variations in the above-mentioned instructions, there is robust consistency in detection of these networks, suggesting that low-level physiological noise, task load (fixation), eye movement, or the presence of visual input cannot influence the results. 39 Furthermore, these large-scale intrinsic resting-state networks (RSNs) appear to reflect a fundamental aspect of the brain's organization and are consistently apparent across waking states, including task performance, sleep, 40 and even general anesthesia. 41 At least 10 organized RSNs have been identified during rest, including the default mode network (DMN; Fig. 2 ), with each one reflecting specific functions that cohere to the intrinsic connectivity patterns (i.e., language, attention, executive functioning, salience, sensorimotor activity, or mind wandering). 42 – 45

RSN partition and global fc variability of other networks with the frontoparietal network (FPN). (A) Shown is the network partition of 264 putative functional regions in 10 major RSNs identified at rest through independent component analysis. (B) The connectivity between the FPN and all other RSNs and associated mean variable connectivity are shown. The FPN is believed to act as a hub to enhance connectivity between all other RSNs. Adapted, with permission, from Cole et al. 45

A critical consideration in the interpretation of spontaneous LFBF is the extent to which it is due to specific functional behavior or mentation. There is evidence that varied mental content during the resting time period can modulate functional activity across RSNs, suggesting content has an effect on functional variations in LFBF. 46 , 47 This would seem plausible given that people are engaged in unconstrained mind wandering while laying quietly awake in a magnetic resonance imaging (MRI) scanner, with a variety of mental content to account for low-level task activation. 47 Yet, there are a number of arguments 38 supporting the idea that mentation during mind wandering is unlikely to be the dominant source of LFBF. 38 Nevertheless, task relevance is often difficult to determine with SIT, unless it is in direct contrast to some attentionally demanding task. Mental content during mind wandering may indeed be of critical importance to task-related processing (e.g., memory consolidation, prospection) or to other ongoing processes that are fundamental to self-specificity. 14 , 48 , 49 Spontaneous fluctuations found in RSNs are believed to be regulated differently than task- or stimulus-driven brain activity. One popular theory holds that the intrinsic activity from LFBF may be more closely related to long-range coordination of higher frequency electrical activity that facilitates coordination and organization of information processing across several spatiotemporal ranges. 50 , 51 Metabolic demands at rest also do not suggest a strong correlation with cellular activity; 8 , 10 , 51 yet, the resting state does not reflect a zero-activity physiological baseline from which attention manifests.

The resting state has historically been referred to as the default mode, because it has been thought to reflect the dominant mode by which coordinated intrinsic activity ongoing at rest is defaulted to, and to which it returns when attentional demands cease. 8 Despite its regular occurrence, not all minds wander to the same degree; there are stable differences among individuals in the propensity to experience SIT and engage the DMN. 14 , 52 Nevertheless, the reciprocal relationship between the passive task-negative state of rest and the active task-positive states is thought to support two fundamentally different modes of information processing—one serving internally oriented attention and another serving externally oriented attentional demands. The DMN shows the most robust anticorrelation with attentional networks, apparent during externally oriented tasks, suggesting that it is fueling task-negative internally directed functional activity.

The DMN, also described as the hippocampal– cortical memory system, 53 , 54 has most consistently been shown to include the ventral posteromedial cortex (vPMC; including posterior cingulate cortex (PCC) and retrosplenial cortex), ventral medial prefrontal cortex (vmPFC), posterior inferior parietal lobe (pIPL), hippocampus, and lateral temporal lobe. 36 , 39 , 55 , 56 The DMN has occasionally been reported to also include the dorsomedial/rostromedial PFC (including BA 8, 9, and 10), rostral anterior cingulate cortex (rACC, or anterior medial PFC), insular cortices, and temporal pole. 52 , 57 , 58 Interestingly, these additional regions have been implicated in task-positive networks and goal-directed activity, suggesting possible overlap of networks with potential functional relevance, and apparent nonstationarity or change over time seen in typical functional connectivity (fc) analyses. 58 Such observations of nonstationarity also suggest a problem with implicating one network supporting a rapidly changing mental state at rest. 47 In fact, some recent work has suggested that the DMN may be broken into multiple subsystems that subserve different dimensions of stimulus-independent or stimulus-oriented mentalizing during the resting state. 52 , 59 , 60

Notably, core DMN regions have been reported to support active states associated with self-reflective, evaluative processes in addition to supporting passive mental states of rest, further suggesting that the resting state involves internally oriented evaluative processing. 36 , 52 , 61 – 63 Self-referential processing involves taking one's self as the object of attention and making judgments or evaluations of one's own thoughts, emotions, or character. 34 , 57 These functional roles have provided the basis for the characterization of the DMN as an evaluative network and has implicated the network in both spontaneous and volitionally mediated mind wandering. 49 The primary nodes of the DMN (PCC and vmPFC) are particularly noteworthy because of their anatomical connections and corresponding functional roles. For example, the vmPFC has direct anatomical connections to the hypothalamus, amygdala, striatum, and brainstem, providing input necessary to process emotion, motivational states, and arousal. 64 Its functional role in coordinating and evaluating basic drives associated with mood, reward, and goal-directed behavior is also strongly supported by the abovementioned anatomy and by its activity in functional brain imaging studies, animal experiments, and behavioral observations in patients with vmPFC lesions. 65 , 66 The PCC is considered to be a network hub with dense anatomical connections across the brain and in particular with the medial temporal lobe, making it and neighboring regions of the vPMC well suited for mediating autobiographical memory retrieval and self-referential processing. 43 , 67 Recent studies have suggested that vPMC activity may be functionally reduced to being “attached to” and “getting caught up in” one's experience, whether it be self- or other-focused, or negatively or positively valenced. 68 In this context, self-reflective processing consumes one's cognitive resources and interferes with ongoing task demands and/or embodied behavior.

A large body of research on the resting state now supports the involvement of the DMN in a diverse array of cognitive processes that are associated with negative or maladaptive mood states, such as rumination, craving, or distraction. 14 , 34 , 68 There is evidence that, in most forms of psychopathology, the DMN is hyperactivated and hyperconnected, showing abnormally high activation during goal-directed tasks. 34 These data suggest that task-dependent downregulation is not as apparent and that patients suffering from psychiatric disorders may be more easily distracted by internal ruminations. 69 Furthermore, greater suppression of the DMN during task performance has been shown to improve accuracy, memory encoding, retrieval, andconsolidation. 70 – 72 Greater DMN activation just prior to a stimulus predicts attentional lapses and decreased accuracy, further providing evidence for its potential role in distraction. 72 However, despite the predominant interpretation that DMN activity is indicative of maladaptive functional processes, this interpretation may be overly simplistic. SIT and associated DMN activity have been characterized by content that is adaptive and constructive. 6 , 57 For example, in healthy individuals, SIT has been shown to facilitate insight, creative problem solving, cognitive control, and prospection for simulating future possible outcomes. 12 , 22 , 73 , 74 The critical point here is that the costs and benefits of DMN activation are context dependent. 14 , 75 Indeed, Smallwood and Andrews-Hanna 14 proposed the context-regulation hypothesis, which states that self-generated thought under conditions that demand continuous attention is unproductive because it can be a source of error, but under nondemanding conditions, it has the potential for benefit.

Although some may argue that there is no apparent functional relationship associated with spontaneous, intrinsic activation of the DMN, an argument can clearly be made claiming the benefit of spontaneous or intentional DMN activation as it reflects our sense of self-identity. DMN activation supports conceptual, linguistic, and symbolic forms of self-representation involving a form of “mental time travel,” which explicitly provides a sense of coherence and continuity with our sense of self in the present moment by allowing one to project representations of self into the future and retrospectively to the past. 14 , 76 Tulving 76 described this mnemonic process involving episodic forms of autobiographical memory as “autonoetic consciousness,” suggesting a conceptual knowing and awareness of self in real time. Tulving and others 77 – 80 argued that this uniquely human ability c provides the necessary cognitive structure for advancing intelligence, building on existing knowledge, discriminating ethical and adaptive behavioral responses to the environment, and “day dreaming” for advanced forms of cognition. One could then imagine that, without opportunities to cultivate autonoetic consciousness, mistakes would be repeated, decisions would be poorly informed, and a sense of identity would be lacking. Mind wandering and the associated DMN activity may, therefore, reflect intrinsic capacities that are necessary to navigate the complex social environment in which humans exist. 14 , 81 Indeed, maintaining a sense of continuity of the self, with reliance on mnemonic processes and DMN activation, contributes to the highest functional and metabolic demands of the brain during waking states.

Mindful awareness: stillness in concentration

From the classical Buddhist Abhidharma perspective, stability and stillness of mind provide freedom from destructive types of emotion and cognition (e.g., anger, craving, greed, lethargy, hyperexcitability) that are rooted in excessive self-absorption or perseveration. 4 , 82 The following metaphor is commonly used to describe how the foundation of mindfulness may contribute to the benefits of a still mind, focusing on cultivating attentional stability and reduced unintentional mind wandering. If a stone is tossed into a still lake, the ripples are clearly visible. Yet, when that lake is unsettled, a single stone's effect is barely noticeable. The same is true of the mind, 83 in that a restless mind that is fraught with many thoughts and emotions is easily distracted, inefficient, and unable to adequately encode information for later retrieval. Furthermore, if one leaves a glass of muddy water still, without moving it, the dirt will settle to the bottom, and the clarity of the water will shine through. Similarly, in mindfulness-based meditation, in which attention is trained to continually return to a single point of concentration, thoughts and emotions settle into what is described as the mind's natural state of stillness, ease, equanimity, and sensory clarity. 3 , 84

In the text Stages of Meditation , an 8th century Indian Buddhist contemplative, Kamalasila describes 10 sequential stages of attention training, referred to as “taming the mind” or “calm abiding” (Pāli: samatha ) that begins with an effortful form of focused attention (FA) and progressively advances toward a state of effortless and objectless awareness. 82 Stability of attention refers to sustained concentration and vigilance that remain unperturbed by distraction or interference from discursive mind wandering, while clarity refers to the phenomenal intensity with which sensory or mental content is experienced. 82 , 85 Insight practice (Pāli: vipassana ), a form of open monitoring (OM) meditation, typically follows calm abiding training with the goal of facilitating meta-awareness of one's own mental habits, increasing the aperture of awareness to all sensory and mental objects that naturally arise and pass. Mindfulness meditation is often taught as an interplay between calm abiding and insight meditation. Therefore, according to the classical Buddhist Abhidharma, one depiction of a restful mind is one that requires concentration, but is calm, alert, and holding an object or stream of objects in effortless awareness.

Although the breath is the most commonly described object of focus in historical Buddhist contexts (e.g., Satipatthāna sutta ), concentration may be on any internal or external sensory object across modalities, the temporal flow of objects arising and passing through space/time, or the restful state where no objects are present ( Table 1 ). One particular contemporary mindfulness system, the Basic Mindfulness system, 86 was developed by Shinzen Young with multiple Buddhist traditions in mind and uses an algorithmic approach that teaches individuals to note and label any experience in three modalities (visual, auditory, or somatic). Sensory objects can be noted and labeled as they arise and pass in OM meditation, or there can be a concentrated focus on one particular modality and experience (i.e., subjective, objective, rest, or flow). A focus on rest is one particular concentration method for cultivating a quiet mind with specificity in each modality, such that absence of the sensory object becomes the object of focus and any impulse to engage with external or internal sensory objects is regulated. Young 86 describes “see rest” as a focus on the “gray-scale blank” with eyes closed or “into image space but not at an image” with eyes open; “hear rest” is described as “mental quiet” or “physical silence” around the practitioner; “feel rest” is referred to as a focus on the “physical relaxation and absence of emotion in one's body.” The different levels of absorption, modalities of concentration, and associated objective neurophysiology have yet to be fully characterized.

Note: The subjective labels “see in,” “hear in,” or “feel in” allow for noting internal sensory experience; “see out,” “hear out,” or “feel out” allow for noting objective sensory experience; “see rest,” “hear rest,” or “feel rest” allow for noting sensory rest; and “see flow,” “hear flow,” or “feel flow” allow for noting the flow of sensory objects across time. 86

Meditative concentration is sometimes referred to as “one-pointedness” (Sanskrit: samādhi) or “absorption” (Pāli: jhāna ). In Tibetan, samādhi is translated as ting nge dzin, where the syllable dzin means “to hold” and the syllable nge is an adverb meaning “to hold something unwaveringly.” The Nikāyas mention variations of samādhi and give descriptions of deepening levels of absorption on the object of attention. Four stages of absorption on form (Sanskrit: rupa jhānas ), four on formless ( arupha jhānas ), and total cessation of perception and feeling ( nirodha-samapatti ) are described in progressive stages of concentration and stillness. At the fourth stage of the rupa jhanas, the mind is focused on a “material” object with equanimity and a narrow aperture of awareness ( Fig. 1 ), such that no other sensory stimuli can enter awareness. By the first formless stage, the meditator achieves insight that there is no longer an object, but rather infinite empty space. The formless states and nondual awareness appear to have similar characteristics, none of which have yet been clearly distinguished in cognitive neuroscience. Stages of jhāna practice have been observed in one functional MRI (fMRI)/electroencephalography (EEG) case study of a long-term Sri Lankan Khema practitioner who was able to progressively move through each of the eight stages of form and formless absorption practice. 87 This study found decreased BOLD activity relative to the resting state and a basic state of concentration (access concentration) across visual, auditory, language, and premotor regions of interest; slight increases in the rACC and ventral striatum; and a shift to lower frequency α and θ bands in EEG. 87 Interestingly, the study suggested that ventral striatal activity corresponds to the subjective experience of joy during early stages. In the historical Hindu context of the yoga suttas, samādhi is believed to represent nondual or transcendent states of conscious awareness and absorption where the sensory or mental object is known directly, beyond name and form, and a feeling of unity or oneness is experienced with the object of meditation. 88 – 91 These descriptions of concentration practice suggest that, through practice and depth of concentration, mental quiet shifts from stable perception of an object to a state of nondual awareness where there is a dissolution of self–object distinctions.

In contemporary contexts, comparisons have been drawn between states of mindfulness in concentration and experiences of “flow,” “the zone,” peak states of performance, and the opposite domain—“zoning out.” Although there are clear similarities of samādhi with states of flow, distinctions can be made. Critically, samādhi is described to involve intentional blocking of sensory information and yet allowing motivationally relevant information to enter conscious awareness. 4 Without volitional control, absorption in an object with focal awareness may also be maladaptive, such that inhibitory processes prevent pertinent sensory information from arising to conscious awareness, potentially leading to an overwhelming sensation and maintenance of emotional reactivity related to the object of focus. 93 Furthermore, the experience of zoning out, as is commonly experienced during a temporally extended, exogenous attentional process that involves low arousal or does not require analytical or critical discernment (e.g., watching television), has also been described as an “intense immersion in the moment;” yet, the individual “typically loses touch with the socially, culturally, and historically constructed world in which he or she lives.” 94 This has been described as “meditation sickness” in Zen traditions that heavily emphasize methods that focus on achieving “inner stillness” over those that engage with the scriptures or discriminate right from wrong in an analytical or critical way 94

Mindful awareness: stillness in nonduality

Later stages of both jhāna and samatha practice place less emphasis on engagement and disengagement with objects of attention and more with nonduality, which refers to the eventual dissolution of subject–object distinctions, nonconceptual awareness, and a phenomenology described as the true nature of mind—an ultimate form of stillness. 82 , 85 Nonduality is most commonly equated with the concept of reflexive awareness (Sanskrit: svasamvitti ) 95 or “bare attention,” coined by the German-born monk Nyanaponika Thera in his book, The Heart of Buddhist Meditation . 3 This nonconceptual emphasis on living in the here and now is believed to have contributed to the foundations of contemporary mindfulness and of the therapeutic recipe for well-being. 94 , 96 In traditional nondual practices of mindfulness (e.g., Chan, Zen, Mahamudra, Dzogchen), 97 there is emphasis on the subject–object distinction as the root of suffering. The Sanskrit author Santideva describes this state of stillness as “remaining like a piece of wood,” such that any impulse toward a particular thought, emotion, or behavior can be heedfully detected but denied full engagement before the mental event requires cognitive resources. 97 , 98 The general instructions for Mahamudra practice are, “Do not chase the past; do not invite the future; rest the awareness occurring now in a clear and nonconceptual state.” 97 There is clear instruction to avoid self-reflective processing and maintain focus in the present; yet, the idea in this practice is not to cultivate a state of samādhi, but rather to release any effort, let go, and not engage with any object. In contrast to the stillness derived from focused concentration, the nondual emphasis is believed to cultivate stillness through an objectless focus. The nondual state has been referred to in Tibetan styles of Dzogchen as “open presence” (Tibetan: rigpa chogzhag ) and also as “awakening” (Pāli: bodhi ) or “nibbana.” Many Buddhist traditions see this as a goal state, where there is a cessation of all “unwholesome” states and all phenomena, including space and time. 99 Understandably, this state of awakening is highly contextualized in the schools of Buddhism from which they are originally described, and there has yet to be objective evidence for the reproducibility of this state. However, the state of open presence has been most closely associated with a nonreferential form of compassion that has been shown to dramatically increase -γ -band activity in advanced meditators across frontal and temporoparietal regions. 100 This activity was also found to correlate very closely with subjective reports of clarity during the practice and remain high in amplitude even after the meditation was complete. 100 γ-Band synchrony is believed to reflect control and temporal binding of local neural activity by distributed neural networks. 101 Theories of attention specify that continuous activation of task-relevant brain areas is driven by high-frequency γ-band activity, and greater magnitude of activity reflects stronger links between attention and sensory inputs. 101 Other neuroimaging experiments on nondual states have demonstrated unique, weak anticorrelations between the attentional networks and the DMN in comparison to stronger anticorrelations during FA practice, suggesting less inhibitory tone over other incoming sensory or mental input. 102 Although both concentration and nondual approaches appear to cultivate stillness in unique ways, the qualitative phenomenology may indeed be similar.

Mindful awareness and discernment versus mind wandering and evaluation

Recently, a number of studies have suggested a therapeutic role of mindfulness-based therapies in neuropsychiatric settings, in which symptoms are reduced explicitly through the reduction of persistent DMN activity and associated narrative self-processing interfering with goal-directed tasks. 103 – 108 This is particularly emphasized in contemporary mindfulness settings where nonconceptual awareness or nonjudgment is emphasized. Indeed, the practice of various styles of mindfulness-based meditation purportedly involve a decrease in self-reflective processing and evaluation. 28 , 30 It is therefore not surprising that, across styles of practice, meditation is found to inhibit activity of nodes within the DMN, similarly to any goal-directed task. 104 , 109 – 114 Furthermore, reports of improved quality of the meditation state 115 or greater meditative experience 116 have been associated with greater decreases in magnitude of activation in primary nodes of the DMN. The PCC, a major node in the DMN, has specifically been targeted for real-time neurofeedback, with the goal of improving one's stability of attention across styles of meditation. 115 , 117 Such results support the idea that meditation practice is undeniably an active cognitive process, and with greater expertise, the magnitude of the inverse correlation with DMN activity becomes greater, 109 suggesting that greater levels of effortless concentration may more robustly reduce activation in the DMN. Generally, one would expect such deactivation of the DMN during any goal-directed task, especially in contrast to a nonmeditative state following instructions to the mind wander 38 or in contrast to a task that specifically recruits self-reflective processing. 118 However, without any explicit instruction to process internal information in a discursive, narrative self-focus, a nonmeditative rest condition may no longer reflect the same mental content, process, or valence for an advanced meditator as in a novice practitioner. In fact, recent data have suggested that meditative expertise may transform the resting state into one that is more similar to a meditative state. 109 , 119 Furthermore, recent studies have demonstrated that spontaneous mind wandering that engages the DMN may still be apparent, but less frequent, during meditation or during nonmeditative states. 105 , 120 Yet, the contrast between a traditional nonmeditative resting state and particular styles of meditation provides considerable insight into the restful mind and how it engages with mental objects with and without awareness.

Although these results appear to suggest that mindfulness is involved in suppressing the DMN and associated self-reflective processing, this interpretation may be an oversimplification for the explanation of meditative expertise. Mindfulness is not merely the opposite of mind wandering, nor is it necessarily always present focused (see Refs. 94 and 96 ). Upon closer inspection of the meaning of mindfulness from the Sanskrit, Pāli, or Tibetan translations, there is a controversial emphasis on cognitive processes “to recollect,” “to bear in mind,” and “to remember.” 2 , 94 , 96 This is in contrast to the typical instruction to stay in the present moment of awareness without judgment. 121 Across schools of Buddhism, two aspects of mindfulness are often described, one in which there exists a nonconceptual state of awareness (Pāli: sati ) and another that involves discernment (Pali: sampajaňňa ), d requiring active reflection, judgment, and action in relation to the sensory or mental objects observed. 2 , 4 In fact, the compound sati-sampajaňňa is often found in the classical Abhidharma or Nikayas to describe a state of mindfulness. 84 Discernment is a cognitive process that reflects continuous access to, and appraisal of, the objects of attention as they arise, so that no thought can be developed into action unchallenged. 2 It facilitates recollection of Dharmic teachings and primes prosocial motivations. It is a process described to help eradicate mental afflictions and motives that potentially affect self-development on a moment-to-moment basis. 122 Without such discernment, the Abhidharma continues to explain that the mind begins to wander toward afflictive thoughts and emotions. Mindfulness and discernment are also described to develop a self- or meta-monitoring faculty that can detect when the goal state of concentration on a particular object has shifted and support a reorientation of attention to the goal-relevant object. This form of meta-awareness implies a nonconceptual, second-order, embodied reflection on experience as a form of experience itself and that is not entangled in the contents of awareness. 123

Given such descriptions, we hypothesize that a state of mindful awareness critically involves rapid flexibility between brain networks that are contextually driven by specific mind states of the practitioner. Building on previous models of mindfulness-based meditation processes, 28 , 30 , 124 we propose that a frontoparietal control network (FPCN) is appropriately situated to couple with, and integrate information across, other contextually relevant networks. The FPCN has the potential to support a volitional focus of stable attention and nonconceptual meta-awareness across bodily systems with a high level of sensory clarity and facilitate rapid discernment and evaluation of each object without strong engagement as mental objects arise and pass in the practitioner's phenomenological space ( Figs. 1 and ​ and3). 3 ). As described by Cole et al. , 45 the FPCN is believed to act as a hub to enhance connectivity between all other RSNs.

Comparison between mind wandering and OM meditation. Evaluative processes and associated DMN activity process visual, auditory, and somatic modalities and inhibit FPCN, VAN, and DAN attentional networks from gaining meta-awareness. The VAN (vlPFC and TPJ) is critical for reorienting, while the DAN (FEF and IPS) is critical for sustaining attention. Mind wandering and OM meditation process the same inputs (visual, auditory, somatic). OM has increased activation of attentional networks and flexible switching between networks. Mind wandering has less connectivity across networks and therefore lacks the meta-awareness to detect unintentional self-reflective or evaluative processing. The FPCN not only acts as a hub for detecting irrelevant mind wandering, but also for facilitating rapid discernment and evaluation when contextually appropriate. Thickness of lines represents proposed strength of connectivity between networks. SMA/PMA, supplementary and premotor areas; IPS, inferior parietal sulcus; pIPL/aIPL, posterior/anterior inferior parietal lobe; PI, posterior insula; AI, anterior insula; dmPFC, dorsomedial prefrontal cortex; vmPFC, ventromedial prefrontal cortex; r/dACC, rostral/ dACC cortex; S1, primary sensory cortex; PCC, posterior cingulate cortex; RSP, retrosplenial cortex; FPCN, frontoparietal control network; VAN, ventral attention network; DAN, dorsal attention network; FEF, frontal eye field; FPC, frontopolar cortex; dlPFC, dorsolateral prefrontal cortex; vlPFC, ventrolateral prefrontal cortex; MT+, middle temporal visual area; TPJ, temporoparietal junction; RSP, retrosplenial cortex; sc, superior colliculus; sgACC, subgenual anterior cingulate cortex; HF, hippocampal formation.

The dorsal attention network(DAN)is associated with externally directed cognition, including covert and overt shifts of attention, eye movements, and hand–eye coordination. 125 It increases in activation at onset of search, maintains activity while awaiting a target, and further increases when targets are detected. 73 , 125 , 126 It is bilaterally represented and includes frontal eye fields (FEFs), ventral premotor cortex, superior parietal lobe, intraparietal sulcus (IPS), and motion-sensitive middle temporal area (MT+). 54 The DAN facilitates orientation in the sense that it is engaged by cues that prime the system for forthcoming stimuli. 126 In contrast, the ventral attention network (VAN) is not engaged by predictive cues and, in fact, is kept under inhibitory control, likely by top-down regions, such as the dorsolateral prefrontal cortex (dlPFC), for the purpose of reducing distraction or allowing unintended information from flooding conscious awareness. 125 The VAN is strongly right-hemisphere dominant and includes the temporoparietal junction (TPJ) and ventrolateral PFC (vlPFC) as major nodes. The VAN continues to direct attention to salient and behaviorally relevant sensory stimuli outside the focus of processing maintained by the DAN. 126 The FPCN has been shown to have extensive connectivity with both the DMN and attentional networks (DAN, VAN), supporting the potential to flexibly couple with either network, depending on task demands. 73 The FPCN includes the VAN, nodes of salience (dorsal anterior cin-gulate (dACC) and AIC)) and executive control networks (dlPFC), as well as the anterior inferior parietal lobe (aIPL), frontopolar cortex (FPC), and dmPFC. 54 , 73 Together, this circuit is believed to link sensory representations to motor maps and facilitate the critical meta-awareness function that then engages a circuit breaker for sustained attention and reorientation of attention as new objects arise and pass. 126 Although frontal areas are responsible for voluntary executive control, parietal regions in concert with frontostriatal circuitry are more involved in stimulus–response associations and would likely become more critical as effort decreases. 126 The DAN and VAN may communicate through the FPCN when there is an intention to actively manipulate the information for some purpose. For example, the VAN is critical for semantic retrieval in the context of inhibitory control. 127 Through a relatively short temporal window, it has been proposed that the FPCN may help link active attentional processes associated with sustained vigilance and alerting with the semantic retrieval and reorientation of attention to task-relevant, but currently unattended, stimuli facilitated through the VAN. 126 The FPC takes up a uniquely large volume of space in the human brain, 128 is a critical node of the FPCN, and is thought to be differentially sensitive to changes in demands for stimulus-oriented or stimulus-independent attention along a lateromedial dimension. 74 This may be why this region is sometimes included in the DMN and at other times included with the frontoparietal or executive control network. 52 , 60 , 63 One study observed the recruitment of both rostromedial and lateral FPC during mind wandering with a lack of awareness; whereas, mind wandering with awareness was found to recruit nodes of attentional networks (lateral PFC and dACC) in addition to the PCC/precuneus, TPJ, insula, and temporal pole, suggesting a processing overlap that could account for poor task performance. 63 Yet, future research will have to clarify whether this type of retrospective experience-sampling method represents a form of nonconceptual meta-awareness that is likely in meditative practice or meta-cognition to involve some level of “mental stickiness” and contributes to distraction and future planning.

Although some methodological challenges remain in interpreting some of the existing initial findings for network interactions (see Ref. 31 ), recent cross-sectional fc studies of meditators have generally demonstrated increased connectivity between the two main nodes of the DMN (PCC and vmPFC) and between nodes of the DMN and salience and executive networks during a nonmeditative resting state. 109 , 111 , 114 , 129 – 132 These studies reflect changes that are sustained in nonmeditative states. In a small number of studies, increased fc has been found between DMN nodes and task-positive regions (e.g., dACC, dlPFC) during and across styles of meditation practice ( Fig. 3 ). Although some of the methodological discrepancies are difficult to interpret, these preliminary studies support the hypothetical flexible switching between networks and the potential functional relevance between nonconceptual awareness and discernment.

There is now evidence to suggest that the FPCN may be actively recruited through both OM and FA meditative practice. 133 – 135 Recent meta-analyses of both morphometric and functional neuroimaging studies of FA and OM have demonstrated increased size and activity in regions of the brain associated with the FPCN (FPC, dACC, dmPFC, dlPFC), areas also associated with the salience and executive networks. 133 , 135 Parts of the DMN (PCC, pIPL) have been shown to decrease in activity during OM and FA mindfulness–based practices. 134 , 135 These data suggest mindful awareness may not only contribute to a quiet mind embedded in concentration, but may also be critical for allowing individuals to flexibly switch between externally and internally driven processes in a volitional manner, drawing from inner reflection and focusing externally with more control than a control population. 30

Thus, a more nuanced reflection on the state of mindfulness, especially in the context of OM meditation, demonstrates significant similarities, and an interaction, with a state of mind wandering. Both mind wandering and OM meditation involve attentional orientation to mental objects arising and passing with each moment ( Fig. 1 ). Yet, subtle differences in attentional engagement, task relevance, emotional reactivity, and perceptual clarity determine the extent to which each state, and the content associated with each state, contributes adaptively (or not) to current mood or future behavior. In the context of OM meditation, 30 , 124 , 136 thoughts or emotions may arise, but the practitioner is typically instructed to refrain from engaging purposely with the content and to rather remain a witness as a nonattached observer to the content as it arises and passes without any form of appraisal. Such attentional processing will reduce cognitive elaboration and, thus, increase the speed at which one may disengage from objects of attention or reduce mental stickiness—a concept often described in contemporary mindfulness 137 , 138 as a disengagement deficit, more often found in SIT, and as a natural tendency to dedicate resources to an object of attention, such that few resources remain to capture any other pertinent environmental information until one is able to disengage and reorient. Over time, this form of mental stickiness on particular emotional stimuli can become habitual, contextually dependent, and highly automatized into the sensory–affective– motor scripts and schemas that dictate tendencies toward behavior. 139 – 141

There is some evidence suggesting that intensive training in meditation techniques reduces mental stickiness by enhancing monitoring of attention, 142 increasing a distributed attentional focus, 143 – 145 enhancing speed of attention allocation, engagement, and subsequent disengagement from serially presented objects of attention. 146 One of the best examples of this decrease in stickiness, or faster disengagement, in the extant meditation literature is shown by data from an attentional blink task 147 by practitioners who completed 3 months of intensive meditation training. 146 A smaller attentional blink and reduced brain-resource allocation to an object of attention (the first target) were found, as reflected by a smaller target 1 (T1)-elicited P3b, a brain-potential index of resource allocation peaking around 300–450 ms ( Fig. 4 ). 146 Those individuals with the largest decrease in brain-resource allocation to T1 generally showed the greatest reduction in attentional-blink size, and improved detection of T2. These observations provide strong support for the view that the ability to accurately identify T2 depends on the efficient deployment of resources to T1. Such data are also suggestive of reduced elaborative processing in the context of goal-directed activity. It should be clear that this process of discernment and evaluation may be operating below conscious awareness, at the level of nonconscious perceptual processing—an aspect of attentional filtering that has previously been described as a potential source for affective and attentional bias. 29 , 148 , 149

Brain potentials from electrode Pz, time-locked to T1 onset on short-interval trials (220–440 ms) as a function of session, T2 accuracy, and group. Selective reduction in T1-elicited P3b amplitude in no-blink trials is evident in meditation practitioners. Adapted, with permission, from Slagter et al. 146

In this article, we illustrated how the phenomenology of a restful mind can take adaptive or maladaptive forms that are context and content dependent. A sense of peace and quiet in the mind is proposed to arise through mental training in concentration, nonconceptuality, and discernment, in contrast to the untrained frenetic restlessness of mental time travel that is characteristic of daily activity in the postmodern setting. The frenetic resting state and associated brain network dynamics are believed to help scaffold attention and emotion throughout everyday waking life, but with the potential to interfere with cognitive performance, mood, and affect when mind wandering occurs in the context of cognitive demand. Mindfulness-based meditation is often viewed as the antidote for mind wandering, positing an overly simplistic polarization of mind wandering as bad and mindfulness as good. However, building on existing efforts to introduce a more nuanced perspective on the relationship between mindfulness and mind wandering, 32 we describe a potential neurocognitive framework in which mental training associated with mindfulness allows the practitioner to more skillfully gain volitional control, flexibility, and awareness over mind wandering, evaluation, and associated DMN activity without necessarily suppressing or avoiding the flow of mental content. Considering the functional role and dynamics between RSNs is complex, and, thus, the exact role played by the DMN and other attentional networks is likely to be context specific and modulated by the specific practices in which an individual engages. As a function of the situational demands, the FPCN is specifically proposed to rapidly and flexibly couple with the DMN and other attentional networks for contextually appropriate engagement and disengagement with relevant objects in the ongoing stream of mental and sensory content. Thus, a sense of tranquility or stillness of mind involves the elimination of distortions and distractions in an effortless and sustained form of awareness and can have lasting effects on one's mental habits, biases, and worldview in relation to the surrounding world. It is likely that a highly developed meta-awareness in the context of mindfulness-based practice may offer a key mechanism for rapid discernment of what is relevant at early stages of attentional processing while also providing sensory clarity and emotional stability through each moment of experience.

Unfortunately, there is a particular rhetoric surrounding the emphasis of nonconceptuality, nonjudgment, and present-moment focus that continues to lead to ethical, social, and developmental passivity in the contemporary mindfulness movement. Given the secular emphasis of mindfulness on the present moment, there is regrettably less emphasis on the benefits from an efficient ability to draw consciously from past experiences and the capacity to reflect inwardly. On closer inspection of the state of mindfulness, we discuss here the benefits of judgment, evaluation, conceptuality, and DMN activity to provide a more nuanced description of brain network interactions and the benefits delivered by these meditation techniques that are continuing to emerge in contemporary society. More broadly, these skills are not emphasized for personal gain, but rather to ultimately nurture the human connection and sense of meaning and purpose that provides the foundation for the benefits of realizing stillness.

Although the current theoretical analysis remains speculative, continued consideration of the resting state in comparison to meditation practice is likely to reveal specialized insights into brain function, energy metabolism, conscious awareness, and therapeutic relevance for psychiatric conditions. Future research investigating differences between FA and OM practices may help clarify critical differences between focal and ambient awareness, and the ability for individuals to volitionally modulate types of information that enter awareness through engagement and disengagement processes. Other considerations for future research should include tracking phenomenology using qualitative empathetic interviewing skills 150 with explicit second-person methods built into the neuroimaging studies, in addition to correlating first-person reports with third-person measures of brain activity. This method could involve independent, unbiased interviewers who may help participants explicate their experiences in order to direct them toward phenomenological aspects of their experience and away from theorizing about it. Examining the stability of RSNs across meditation states, axiological frameworks, and across a phenomenology of clarity and mind wandering, may better reflect consistent therapeutic targets that are context specific. More consistency across fc analyses will have to involve choosing consistent seeds for analyses and tracking functional changes across states and rest in both clinical samples and meditation-naive subjects who do not have a self-selection bias. As research progresses in this field, it is likely that differences between novice and advanced meditators will become apparent and may account for discrepancies in the ability to sustain/maintain nonconceptual forms of awareness during meditation and the speed with which practitioners can make discerning judgments. Indeed, even the greatest meditators report fluctuations in level of clarity with which meditative quality is experienced over time. Thus, future research would benefit from having closer measurements of neurophysiological changes as they directly relate to first-person reports on phenomenology of experiences, such as clarity in the context of meditation and throughout daily life.

Acknowledgments

The authors express gratitude to A.P. for the constructive feedback. F.Z. and D.R.V. wrote the paper.

a Eliot, T.S. 1943. Burnt Norton. Four Quartets. Orlando: Harcourt.

b Early schools of Theravada Buddhism describe a collection of scriptures and suttas in the Pāli Canon.

c Although Tulving argues that mental time travel is uniquely human, there is good evidence to suggest that scrub jays can cache food in a manner that reflects both planning for the future and some form of mental time travel to retrieve detailed information on when and where the food was cached. 79

d Sampajaňňa is also described in nondual traditions as a form of “monitoring,” rather than “clear comprehension” in Theravadan texts. Thus, this aspect of mindfulness may reflect a state of meta-awareness, decentering, or dereification that reflects an interaction between task-set retention and background awareness. 97

Conflicts of interest : The authors declare no conflicts of interest.