The Free-Range Brain

Daydreams. To-do lists. Obsessive thoughts. Creative flashes. Anxious worry. All these patterns of thinking are variations of “mind-wandering,” according to psychologists. But a new reviewof brain studies is changing how we view these mental loops.

The research, published in the November issue of Nature Reviews Neuroscience, was conducted by scientists at the University of California-Berkeley and the University of British Columbia. The team looked at nearly 200 neuroscience studies—many of them involving MRIs scanning the brain during normal resting activities. They discovered found interactions between large-scale neural networks that give clues to how the resting mind works.

When the brain is focused on a task, the prefrontal network—think of it like Mr. or Ms. Executive, in charge of planning and impulse control—holds down other brain activity to get the job down. If, on the other hand, the brain is stuck in a negative loop, like worry or anxiety, the emotional brain (the “salience network”) is in charge, smothering off other networks. Now, spontaneous thinking, such as free association, happens best when the controlled thinking is shut off. The researchers think that when at rest, your brain can transition naturally between spontaneous and constrained thought. That’s why you have the sensation that your mind is wandering.

“We propose that mind-wandering isn't an odd quirk of the mind,” wrote the review's lead author Kalina Christoff, a psychology professor at the University of British Columbia. “Rather, it’s something that the mind does when it enters into a spontaneous mode. Without this spontaneous mode, we couldn't do things like dream or think creatively.”

Her study co-author, Zachary Irving, is a post-doc scholar at UC Berkeley. He has ADHD, and wrote, “Everyone's mind has a natural ebb and flow of thought, but our framework reconceptualizes disorders like ADHD, depression and anxiety as extensions of that normal variation in thinking,” said Irving. “This framework suggests, in a sense, that we all have someone with anxiety and ADHD in our minds. The anxious mind helps us focus on what’s personally important; the ADHD mind allows us to think freely and creatively.”

This research may lead to better treatment of disorders such as anxiety, ADHD and depression.