DW Science explainer on the default mode network: what your brain does when you aren't focusing on anything, and why it's important.

The average human brain consumes about 20% of the body's energy despite making up only around 2% of its weight. Interestingly, that stays roughly stable whether you are resting or busy with a complex task. Image: Irina Romanova/Zoonar/picture alliance

You know when you lock your phone and the screen goes black? It seems like it's not doing anything. But it's not doing nothing. It's syncing your messages, updating apps and running other background processes.

Imagine you're sitting on a bus, staring out of a window, taking a shower or walking, and you get that feeling of doing nothing and letting your mind drift?

Well, your mind, the brain, is doing a lot when it feels like you're doing nothing.

It's going over your memories, shaping your sense of who you are, imagining possible futures, helping you understand other people and connecting ideas.

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