It’s happened to us all while reading a book or an article: a sudden lapse of attention followed by the realization that you have no idea what that last paragraph was about. What was going on in your brain the moment before you lost concentration?

Until recently, scientists assumed that our brains were largely dormant during distraction or rest, outputting little more than random noise. But it might surprise you to know that whether you’re focusing on a task, lost in thought, or simply doing nothing, your brain is almost equally active.

In fact, our brains have a dedicated network of interconnected regions thought to facilitate daydreaming and other forms of introspection. In 2001, scientists discovered that the so-called “default mode” network is more active during periods of wakeful rest or distraction, and less active when we’re focusing on an external, goal-oriented task. This network is thought to play a critical role in helping us process social interactions, such as chatting with a friend over coffee, as well as recognizing emotions in ourselves and others. If the network ceases to function normally, some of these processes may start to break down, such as in autism or attention deficit/hyperactivity disorder (ADHD).  

In contrast, a different network of brain regions, referred to as the “frontoparietal” network, is thought to be essential for performing attention-demanding tasks. Regions in this network are more active when we attend to a particular goal or task, and less active when we are at rest, such as during mind-wandering. Thus, the two networks are like children on a seesaw: as activity goes up in one, it goes down in the other.

This ability to switch between passive and attentive brain states may have played a critical role in human evolution, allowing us to remain alert and react to unexpected environmental events during periods of rest. But unfortunately, our brains don’t always get it right; a momentary spike in activity in the default mode network can be enough to throw your concentration. In most cases, the results are harmless, such as forgetting why you walked into a room, or responding to a question more slowly. But in some cases, the consequences can be more serious, causing accidents or injuries.

But what role, if any, does mindfulness have to play? If the default mode network is more active when we’re distracted, and mindfulness encourages us to focus more on the present moment, then perhaps the two could be related?

In 2011, scientists at Yale University put this theory to the test. They compared brain activity in a group of experienced meditators to a group of meditation-naive volunteers, while both groups engaged in meditation. They found that during meditation, experienced meditators had reduced activity in the default mode network and were less prone to distraction, compared to participants that hadn’t meditated before. This was one of the first studies to provide an explanation, in terms of what’s going on in the brain, for why meditation might make us more “present-centered”.

Of course, this doesn’t mean that meditation is the only factor that’s important; we’re all likely to lose focus when we’re tired, stressed, or emotionally distraught. But as you continue with your meditation journey, try to take note of moments where you feel either particularly focused or unusually distracted. You might just find that last night’s reading session was more productive than ever before.