Default mode
A network of linked brain areas, mostly along the middle of the brain, that gets busier when your attention turns inward: memories, plans, daydreams. It quietens when you focus on a task in front of you.
The default mode network is a set of linked brain areas that tend to be active together when you're not focused on the world outside. Evidence: solid Its main hubs sit along the middle of the brain, at the front and towards the back, with links to memory areas deeper in. Evidence: solid In 2001, researchers described how these areas consistently became less active when people started a focused task, and more active again when they stopped, and called it the brain's default mode. Evidence: solid Scans track blood flow and oxygen, so "more active" means those areas were working harder, not switched on from off. Evidence: decent
Where it gets oversold: "the daydreaming network", or the bad one you should switch off. It's also more active when you recall your own past, picture the future and work out what someone else is thinking. Evidence: decent It does go with a wandering mind. In 14 experienced meditators focusing on their breath, it was more active in the seconds when their mind drifted. Evidence: decent In 17 depressed adults at rest, the more it dominated, the more they dwelt on their low mood, and the less they reflected constructively. Evidence: decent While meditating, experienced meditators showed less activity in its hubs than beginners; that's a comparison of two groups, not proof that meditating changed them. Evidence: decent
Why it matters
Ten minutes of sitting still is built on that cycle: drift, notice, come back, with parts of the prefrontal cortex busier during the return. Evidence: decent In phone check-ins, people's minds were on something else almost as often as on what they were doing, and they were less happy when they were, which is where taking a mental photograph comes in. Evidence: decent When the drift turns into going over the same worry, that's rumination. Evidence: decent