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

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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?

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.

A relatively free and empty mind actives a brain network that accesses lots of memories and spits out private random thoughts. These are called spontaneous cognitions; they can be depressive, annoying, creative, or just bland. Share on X

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.

Why does our mind wander?

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 vs. Negative Automatic Thoughts

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 cognition vs. Obsessive thoughts

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.

Mind-wandering vs. Daydreaming

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].

What are the types of spontaneous cognitions?

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.

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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.

Default mode network theory of spontaneous cognition

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:

  1. 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.
  2. 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:

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

The downside of an active default mode network:

  1. Excess activity implies high mind-wandering which may lead to a chain of negative thoughts (rumination)
  2. High frequency of similar thoughts can be distressing
  3. 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.

  1. Most processes don’t reach our awareness and only some that reach become “spontaneous cognitions.”
  2. 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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