A brain experiment you can do right now
Your brain is never switched off.
Not when you're bored. Not when you stare out of the window. Not even when you think you're thinking about nothing. Let's prove it.
The 10-second test
Press start. Look away from the screen. Try to think about absolutely nothing until the count ends.
Two teams, one brain
The daydream team and the focus team
Your brain has big teams of areas that work together, like players on a pitch. Two of them take turns. Flip the switch and watch.
Front of the head is on the left. This drawing squashes the inside and outside of the brain into one picture, so it's a map, not a photo. Tap a dot.
Daydream mode is ON
The orange areas light up and talk to each other. You're remembering, imagining, and thinking about yourself and other people. Tap any dot to see what it does.
💜 The purple dot is the salience network: the referee. It spots when something important happens and flips the switch between teams.
Meet Marcus Raichle. He's a brain doctor (a neurologist) in St Louis, USA, and he'll be your guide on this page. In the 1990s he kept noticing something in brain scans that everyone else threw away. Keep scrolling to find out what.
Make it personal
What has your daydream network done today?
Tick everything you've done in the last 24 hours. Be honest, nobody's watching.
Tick a box to start.
The detective story
How scientists found a network nobody was looking for
This took almost 80 years and several people. Tap each year to open it.
⚡
Marcus's big clue: energy. Your brain is only about 2% of your body weight but uses about 20% of your body's energy. When you start a hard task, that energy use goes up by only a tiny amount. So Marcus asked: if hard work only adds a little, what is all the rest of that energy doing? His answer was that the brain is always busy on its own inner work. The daydream network is part of that.
Brains and health
When the daydream team won't behave
Doctors care about this network because it seems to work differently in some illnesses. Tap a card to flip it. Each card shows how sure scientists really are.
Test yourself
The Daydream Quiz
Have the faith to doubt
What scientists don't know yet
- Brain scans show teamwork, not wires. An fMRI scanner shows areas that get busier and quieter at the same time. That's like seeing two friends always arrive together. It doesn't show the road they travelled on.
- Everyone's map is a bit different. When scientists scanned the same people many times, the network sat in slightly different places in each person. Averages hide this.
- Many studies were too small. A huge 2022 study showed you need thousands of people to find reliable brain–behaviour links. Lots of older studies had fewer than 50.
- No scan can diagnose you. In about 1,800 people, no brain scan measure could reliably tell who was depressed. Doctors still diagnose by talking to you.
- "Rest" is the wrong word. Newer research says this network isn't about resting. It's about using memories and knowledge to understand what's happening, even during some tasks.
🔄
The best bit about Marcus: in 2025, aged well into his 80s, he co-wrote a paper updating his own idea. It gave the "focus team" a proper name: the action-mode network. Good scientists change their minds when the evidence changes.
Where this comes from
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