I can anecdotally attest to this. When I had a piano recital coming up I used to practice very intensely, but would &#x27;hit a wall&#x27; at some point. When I came back to it the next day I&#x27;d find my playing had improved significantly.<p>It almost felt like the gains from practising got stored up somewhere while I was awake, and slowly unspooled while I was sleeping.