Meditation: Mind-wandering & your brain’s Default Mode Network

If you are anything like me, you may have experienced setting out to do something with all of your attention – a work assignment, making dinner or a conversation with your partner – and not long after you notice that your mind is wandering to anywhere but the task at hand. Perhaps imagining yourself on some Thai island or regretting not speaking up on behalf of a colleague a few days ago – wherever your mind was, it was not attuned with the present moment.

If any of the above sounds familiar, then you have experienced the activation of the default mode network (DFN) – a brain region which becomes automatically active when we are not actively fully engaging in a task. Dr. Randy Buckner (Harvard University) describes the DFN as ‘an anatomically defined brain system that preferentially activates when individuals are not focused on the external environment’ – in other words, our default setting which kicks in when we are not engaged in a pressing task, or in wakeful rest.

Researchers looking to measure baseline brain activity found, instead of an electrically ‘quiet’ brain, people at ‘rest’ had lots of consistent brain activity between the medial prefrontal cortex (mPFC) and the posterior cingulate cortex (PCC) – see figure above.

The DFN is a store for self-referential information, the sense of ‘I’ or ‘Me’ – “I need to finish that assignment’, ‘I wish I was on holiday’, ‘does he like me?’ ‘Is that person nice enough for me to approach?’ ‘I should never have said that to her.’ And so on. Thoughts of judgement, evaluation and analysis about the self and others; that narrative which seems to always be on – in other words, we’re thinking about ourselves in some way fantasizing about what we will do in the future or what so-and-so did to us in the past. In fact, a study of 2,250 people conducted at Harvard University found that on average we spend nearly 47% of our waking hours in this mind-wandering state (Killingsworth & Gilbert, 2010).

“A human mind is a wandering mind, and a wandering mind is an unhappy mind” – Sam Harris

Everyone can draw their own conclusions about the impact that mind-wandering or day-dreaming has on them – but a few things that come to mind for me include poor focus leading to a less quality output, or missing out on the finer details of a conversation with a friend and missing out on simple joys which present themselves regularly through the day because of rumination about things which usually have no bearing on life now.

So, what to do?

There is growing scientific evidence to support what ancient Eastern philosophies have been practicing for thousands of years, in that training in mindfulness and meditation can lead to a reduction in activity of the default mode network i.e. a mind at peace in and with the present moment. Mindfulness is simply paying full attention to the present, and accepting what’s going on internally and externally, without judgement. This being aware of the present moment and everything in it, is the opposite of being caught up in daydreaming i.e. switching off and allowing the default mode network to kick in and take over.

Studies by Judson Brewer (Neuroscientist and author of ‘A Craving Mind…’ – a great read on how mindfulness can help break addictive behaviour) and his colleagues at Yale found evidence with fMRI scans that experienced meditators showed a decrease of grey matter around the default mode network, meaning it was less prone to be active (study here in PNAS journal) and a similar study here in National Centre for Biotechnology Information

Further studies have highlighted that those that committed to an 8 weeks mindfulness-based stress reduction training program (MBSR), engaging in different meditation practices daily, were found to experience that the default mode network was less and less active, or in other words a greater capacity to become aware when the mind was wandering off from the present. The practice of meditation usually follows a cycle: focusing attention (on breathing or bodily sensations), noticing being distracted or caught in a train of thought (mind-wandering or self-referential thinking) and returning to the point of focus. Over and over again – just how we train the body’s muscles with repetitive exercises, the muscle of attention is trained during meditation.

And what an interesting experiment on ourselves to find out just how attentive we are when tasked with focusing on something that is always occurring like breathing. So just intentionally sitting in silence doing nothing can literally rewire your brain. Good luck with your practice.