May 15, 2009 If you think letting your mind wander is unproductive then you may be in for a big surprise. A recent study at the University of British Columbia found that our brains are much more active when we daydream than previously thought. What is surprising is that the study also found that brain areas associated with complex problem-solving – previously thought to go dormant when we daydream – are actually more active than when we focus on routine tasks.

The busy brain

In the study, published in the Proceedings of the National Academy of Sciences, subjects were placed inside an fMRI scanner where their moment to moment attentiveness was tracked whilst they undertook mundane tasks. The findings suggested that daydreaming, which can take up to one third of our waking lives, is an important cognitive state in which we may be taking time out from the immediate tasks to sort out important problems.

"Mind wandering is typically associated with negative things like laziness or inattentiveness," says lead author, Prof. Kalina Christoff, UBC Dept. of Psychology. "But this study shows our brains are very active when we daydream – much more active than when we focus on routine tasks."

Until recently, the only parts of the brain thought to be active when our minds wander was the medial prefrontal cortex (PFC), the posterior cingulate cortex and the temporoparietal junction. However these studies indicate that the areas associated with high level problem solving, including the lateral PFC and the dorsal anterior cingulate cortex, also become activated when we daydream.

"This is a surprising finding, that these two brain networks are activated in parallel," says Christoff. "Until now, scientists have thought they operated on an either-or basis – when one was activated, the other was thought to be dormant." The less subjects were aware that their mind was wandering, the more both networks were activated.

The study seems to confirm what many of us intuitively understand - if we "sit" on a complicated problem for a few days or hours and let the cogs of our brain churn away in the background, a solution often presents itself unexpectedly. For information on Christoff or UBC's Cognitive Neuroscience of Thought Laboratory visit Christofflab.

David Greig

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