shower thoughts is a specific instance of diffuse mode thinking
Diffuse mode is when your mind is relaxed and free. You’re thinking about nothing in particular. You’re in diffuse mode when you’re daydreaming or doodling just for fun. If your teacher tells you to concentrate, you have probably slipped into diffuse mode.
When you’re in diffuse mode, you’re gently using other parts of the brain that are mostly different from the parts you use when you are focusing. The diffuse mode helps you make imaginative connections between ideas. Creativity often seems to pop out of using the diffuse mode.
It turns out that your brain has to go back and forth between focused and diffuse modes in order to learn effectively