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The mind that wanders

Updated: Mar 23, 2022

We spend most of our life as humans interacting with our internal thoughts. When we're alone, our brains rarely stay quiet. Our minds may easily go from one issue to the next. You may recall your morning run, then visualize yourself working out, and finally consider what you'll make for supper today. At other times, we consciously limit our thoughts and strive hard to achieve a goal. Sometimes, our minds become hooked on an emotionally charged issue from which we find it impossible to escape. However, such trains of thought can manifest in many ways. But why does the mind wander, and where does it go when it does?

Internal trains of thought have generally been studied in the context of mind wandering, specifically, how internal trains of thought unfold over time. Recent theories are less task-oriented, focusing instead on the dynamics of mind-wandering—that is, how internal trains of thought evolve over time. Within the train of thoughts, the "dynamic framework" of spontaneous thinking differentiates into three types: 1) deliberately constrained, 2) automatically constrained, and 3) freely moving thoughts. The dynamic framework claims that these three sorts of ideas are unaffected by task-relatedness. To put it another way, task-related and non-task-related ideas can be controlled consciously, automatically, or freely.

Researchers examined these four types of thoughts using electrophysiological recording and thought sampling: task-unrelated, freely moving, deliberately constrained, and automatically constrained. By recording an electroencephalogram (EEG) while participants conducted an attention task, researchers were able to evaluate the electrophysiological characteristics of the four categories of thought.

Because electroencephalography possesses the temporal resolution required to record the rapid changes in brain activity related to our trains of thoughts, it captures stimulus-evoked, task-dependent activity and stimulus-independent, intrinsic activity.

The electrical response induced by task-relevant stimuli, known as event-related potentials (ERPs), was investigated initially. When a person has disengaged from task-relevant stimuli, ERPs reveal an electrical trace of this. As a function of each thinking type, three EEG measurements were investigated over various time windows: parietal P3 event-related potentials elicited by stimuli and alpha power (8 to 14 Hz) and variability elicited by non-stimuli. Throughout the exercise, participants were asked a series of thought-sampling questions on the nature of their ideas. In mind-wandering research, thought sampling is the gold standard. The researchers discovered that task-related ideas elicited higher parietal P3 than irrelevant thoughts, while consciously limited thoughts produced higher frontal P3 than uncontrolled thoughts. As more than a dozen research participants' thoughts moved from one topic to another, higher alpha brain waves were found in the prefrontal cortex, demonstrating an electrophysiological characteristic for free, spontaneous cognition. Slow brain rhythms that occur every 8 to 14 cycles per second are known as alpha waves. Meanwhile, weaker brain signals known as P3 were detected in the parietal cortex, providing another neurological indicator for when people are not paying attention to the activity at hand. These findings demonstrate unique electrophysiological patterns associated with task-independent and dynamic ideas, suggesting that these brain measurements accurately capture the diversity of our ongoing thinking mind.

Creativity is all about the production of original ideas and associations through a divergent thought process, which is theoretically equivalent to the free flow of thoughts from one topic to the next. Increased frontal alpha waves during free-flowing cognition and creativity could be interpreted as a sign of unrestricted thinking.

The ability to recognize our thinking patterns through brain activity is an important first step in developing potential approaches for better controlling how our thoughts unfold over time, which can be applied to both healthy and abnormal brains.

Written by: Reem Alzafiri, BSc, MSc.

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