It happens to all of us: You’re in the middle of something, maybe even something important. You lose focus for an instant, and you find yourself on a new train of thought, along for the ride. Your default mode network takes over, and now you’re in a daydream. Maybe you’ll end up on a beach, or an alpine village. Maybe you’ll find yourself on the metro in an unfamiliar town. Or maybe you’ll be attacked by a cacophony of unfamiliar noises, with brief returns to the here and the now. But there’s no escape: When your mind wanders, it brings you along.