What the Default Mode Network Is: Why the Mind Grows Loudest When You Finally Rest

By the time Prae had cleared her work it was nearly midnight. She lay down intending, at last, to give her mind a rest.

The moment her head touched the pillow, the inner speaker switched on. She thought of the curt way she had answered her manager that afternoon — “What must he think of me?” — and the scene cut to tomorrow’s presentation: “What if I make no sense at all?” Then to something from three years ago she had assumed she had forgotten. The more she wanted the thoughts quiet, the louder they became. It was two in the morning before she slept, her body exhausted, while her brain had chosen the least demanding hour of the day to raise every subject at once.

What was happening involves a brain network called the default mode network, or DMN. In short: the DMN is a network of brain regions that tend to work in concert during rest, and during mental activity turned inward — thinking about oneself, memory, the future, and the thoughts of other people. The DMN does not cause overthinking, and it does not switch on only when we are idle. Some research associates its patterns of activity and connectivity with rumination — but that activity is part of the brain’s ordinary functioning, so it is neither abnormal nor something to be eliminated.

What the default mode network is

The default mode network is a group of regions across the brain that tend to operate together as a network. Researchers have found that these regions work in concert more prominently when we are resting, or when attention turns away from the task in hand toward thoughts within. It carries a second name for that reason — the resting-state network — and it becomes less active when we must attend to certain kinds of task demanding a great deal of attention to the outside world. That said, the DMN is not engaged only when we are “doing nothing”, and it does not shut down every time we have work to do, because it also plays a part in activity involving memory, meaning, and thinking about ourselves or others.

Put simply, it is like a mode the brain tends to switch into when no external task is calling for attention — which is where the name “default mode” comes from. And this is why so many people find that the emptiest moments of the day, in the shower, in traffic, or as their head reaches the pillow, are the moments when thoughts crowd in. As external stimulation falls away, the inner thinking that was covered over during the day may become more noticeable, and the DMN is one of the networks involved in mental activity of this kind.

When the DMN engages, and what it does

Studies to date have linked the default mode network with several kinds of mental activity, all sharing one common feature: a turn toward the inner world. Thinking about and evaluating ourselves; revisiting memories; imagining or planning the future; mind-wandering; and considering the thoughts and feelings of other people.

None of these functions are without purpose. The capacity for self-reflection, or self-referential thinking, learning from the past, planning ahead, and understanding other people are all essential skills that let us live as human beings among others. The DMN is not a defect of the brain, but part of its necessary work. It is only when its activity and its coordination with other networks become stuck in certain patterns — or when we find it hard to switch out of inner thinking and back to what is in front of us — that thinking which is ordinarily useful can become a loop that produces suffering.

The DMN is like a storyteller who lives inside

An image that helps: a storyteller who resides within us.

While we are absorbed in the task in front of us, this storyteller retreats and sits quietly backstage. But the moment the lights of the external task begin to dim, the storyteller walks to the center of the stage and starts to speak. Our story. Yesterday. Tomorrow. What other people might be thinking of us. On an easy day it is a good storyteller, helping us review what we have learned, think through what we intend to do, and understand the feelings of the people around us. On a tired or difficult day, the same storyteller may become stuck on a single tale, circling a painful scene again and again without ever finishing. The answer, then, is not to dismiss the storyteller — we still need it — but gradually to help it not remain stuck on the same story, and to find newer, more fitting ones to tell.

The DMN and rumination

The clearest link between the DMN and distress is rumination. Research finds that altered activity and connectivity in the DMN are associated with a tendency toward repetitive self-focused thinking, and some studies find associations with depression and anxiety as well.

Here we should be careful. What most of that research finds is correlation, not proof that the DMN directly causes these conditions, and the overall evidence remains mixed. To say “the DMN is the villain network that makes us overthink” is a facile account, and further than the research supports. A more appropriate statement would be that rumination is associated with patterns in how the DMN works together with other networks governing attention and thought. When the system finds it hard to switch out of self-referential processing, thinking may circle the same content for longer.

And if rumination or low mood begins to grow heavy and persistent enough to affect your sleep, your daily life or your relationships, speaking with a mental-health professional will address it more precisely than trying to order yourself to stop thinking. If distress ever becomes more than you can carry alone, Thailand’s mental health hotline, 1323, is staffed by people who will listen, twenty-four hours a day.

Can we switch the DMN off to find peace?

This question comes up very often, particularly online, where it is frequently claimed that meditation or some other method can “switch off” the DMN and bring peace of mind, or dissolve the sense of self. Let us answer strictly from the research.

Some studies find that people who meditate consistently show patterns of DMN activity that differ from the general population, and that mindfulness practice is associated with certain changes in this network. But findings remain varied, with methodological limitations, and it cannot be concluded that any method can “switch off” the DMN at will. More importantly, the reasonable goal is not to shut this network down, since we still need it to reflect on ourselves and to understand the world. The goal is to train the brain toward greater flexibility — able to move in and out of a reflective mode more fluently, and not caught in a loop of circling thought for too long. Framed that way, it becomes an act of kindness toward yourself rather than an attempt to force the brain into silence.

At NBRH we work on the principle of Neuro-Behavioral Repatterning & Hypnotherapy: adjusting the nervous system’s patterns of response, and behavior, systematically. With the DMN, that work is a matter of flexibility: a pattern of circling thought, walked often enough to become familiar, can gradually become easier to leave through practice and new experience repeated consistently. Lasting care for the mind does not come from forcing thought to stand still. It comes from building the brain’s flexibility, gradually, so that it can move out of a familiar groove more fluently and does not stay in the same scene for too long.

That flexibility reaches well beyond thought alone — “What Neuroplasticity Is” sets out how the brain learns a new route.