Good news for chronic daydreamers: findings from a recent meta-analysis by UBC Psychology researchers Kieran Fox and Dr. Kalina Christoff suggest that mind-wandering may involve many more brain areas than previously thought.
It has been generally accepted that a system of brain regions known as the ‘default mode network’ are the principal areas activated during mind-wandering. This network, which includes areas of the medial temporal lobe, medial prefrontal cortex, and posterior cingulate cortex, is thought to be activated ‘by default’ in the brain when one is at rest and not engaged in any goal-directed activity.
Fox, PhD candidate and lead author, says that the new meta-analysis published in the journal Neurolmage “confirms the involvement of the default mode network, but also shows that just as many brain regions beyond it are involved in mind-wandering, too” – including certain regions previously thought to only be involved in ‘executive’ brain functions. These executive areas, implicated in introspection, planning, monitoring of performance, and other clearly purposeful tasks, seem to be consistently activated during mind-wandering.
“These findings suggest that mind-wandering involves a lot more than just pointless fantasizing, and might very well be involved in complex planning and decision making – even if it’s unintentional or unconscious,” says Fox. “And indeed, if you ask people about the content of their mind-wandering, you find ‘useful’ and goal-related thoughts all the time”.
A 2009 study led by psychology professor Kalina Christoff was one of the first to tackle the topic of the neural correlates of mind-wandering, and that study’s findings also showed activation of the brain’s executive areas. However, these findings seemed rather counterintuitive and the results of other studies on the topic hadn’t always been consistent. Wanting to shed some more light on the topic, the research team decided to conduct a meta-analysis to examine Christoff’s findings as well as a barrage of other neuroimaging studies dating back to October 1996, when the first research explicitly studying the neural correlates of spontaneous thought was published. They searched online databases MEDLINE, Google Scholar, and PsycINFO for peer-reviewed papers containing the terms ‘mind-wandering’; ‘mind wandering’; ‘spontaneous thought’; ‘stimulus-independent thought’; ‘task-unrelated thought’; or ‘daydreaming’, and filtered the results by carefully identifying studies whose methods involved neuroimaging.
What they found supports Christoff’s 2009 results. “Our meta-analysis suggests that in fact these executive brain areas are reliably recruited during mind-wandering,” says Fox, “that the neural correlates of mind-wandering are complex and diverse, and I think this dovetails well with people’s own impression of the complexity of the brain’s wanderings and musings.”
According to Fox, meta-analyses are very useful in the world of neuroimaging because they “aim to wash out the ‘noise’ due to extraneous factors and look for the core neural correlates of a given state or process. This is what we’ve done with mind-wandering, where so far the literature has yielded somewhat contradictory and confusing results.”
Of course, these findings don’t mean that the case of the neural basis of mind-wandering is at all closed – quite the opposite, says Fox. “The fact that ‘higher’ executive brain regions are consistently involved in mind-wandering doesn’t prove anything in and of itself: it doesn’t guarantee that mind-wandering is therefore useful or related to creativity. Future research has to directly make the link between activation in specific brain areas, and complex or creative mind-wandering.”
Luckily for those who are curious about this complex but fascinating topic, Fox is pursuing this exact topic as part of his PhD research.