Rick Robinson

Sep 20th 2021

Do Types of Brain Waves Reflect How We’re Thinking?


Brain waves, produced by micro-voltage electrical currents in the brain, have been on scientists’ minds for about 150 years, according to Stanford University. These electrical fields flowing from the cerebrum were first detected in animals in 1875, then humans in 1929.

EEG machines can detect several distinct types of brain waves, which have long been known to correspond to such broad mental states as relaxation, meditation or sleeping. But linking brain waves to specific thought patterns has proven far more challenging.

However, recent research is providing the first tantalizing hints that our brain waves could indeed provide insights into how we are thinking and, thus, how the brain works. Detecting what we are thinking about — say, whether we are studying math or literature — remains elusive.

How Minds Wander — or Don’t

As Berkeley News reports, a new study by researchers at the University of California at Berkeley suggests that how we are thinking — whether we are highly focused, obsessively fixated on some problem or allowing our mind to wander — can be detected from brain wave patterns.

As is so often the case, the overall design of the experimental study was deceptively simple. As Science News for Students reports, the researchers recruited 39 adults to learn some basic information about patterns of thought, then they had them perform a simple cognitive task. A series of pointing arrows would appear on a computer screen, and the participants would choose an arrow pointing in the same direction.

As each subject did this, a “thinking cap” wired to an EEG detected the types of brain waves the participants generated as they performed the task.

The participants were then asked what their mental state was as they performed the arrow-matching task. On a 1-to-7 scale, they rated whether their thoughts were highly focused on the task, freely wandering or either deliberately or automatically constrained. These internal, subjective reports could then be compared with the brain wave data.

From Subjective Experience to Brain Wave Measurements

Focused on the task or freely wandering are fairly straightforward distinctions. The other two are more subtle. A participant might have been more focused on something interesting instead of the fairly dull experimental task. This is a deliberately constrained thought pattern.

An automatically constrained thought pattern, in comparison, is one that we feel “stuck” on — fretting over an upcoming test, say, or a stressful personal encounter.

What the experimenters found was that people’s accounts of their mental processes while performing the arrow-matching task corresponded closely with their recorded types of brain waves. In particular, Technology Networks reports that “increased alpha brain waves were detected in the prefrontal cortex of more than two dozen study participants when their thoughts jumped from one topic to another, providing an electrophysiological signature for unconstrained, spontaneous thought.”

Alpha waves are relatively long brain waves, with a frequency of about 9 to 14 cycles per second. Previously, they’ve been found to be associated with relaxed and meditative states. The new findings strengthen the link between alpha waves and free-roaming mental states. Another set of weaker brain wave signals, called P3 waves, were also associated with wandering thoughts.

Research team member Alison Gopnik expanded on the implication of this finding.

“Babies’ and young children’s minds seem to wander constantly, and so we wondered what functions that might serve,” Gopnik told Berkeley News. She added that “mind-wandering is as much a positive feature of cognition as a quirk, and explains something we all experience.”

In the Science News for Students article, Lead researcher Julia Kam emphasized that specific brain wave patterns are not intrinsically good or bad. It all depends on circumstances. Focus is good if you are studying for a test. But “wandering” thought patterns are tied to creativity and finding alternate ways to solve a problem.

The Brain Observing Itself

The association of types of brain wave patterns with specific mental states suggests that we can determine thought patterns without needing to ask people their own subjective impressions of how they are thinking. Kam also told Berkeley News that the research could help to detect thought patterns associated with psychiatric and attention disorders.

These disorders are often characterized by being either unable to focus or being unable to break free of a thought we are “stuck” on. Both relate to thinking patterns that don’t fit the needs of the moment.

Meanwhile, other lines of research are also cracking open the doors to understanding brain waves. For example, MIT reports that the interplay of different types of brain waves is linked to why we experience some events as surprises but others as routine.

There may be no more challenging task in science than for the human brain to understand itself. But the new brain wave studies show that we are making progress in grasping how the brain works.

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