Periods of non-sleep deep rest, where attention drifts, are crucial for consolidating neural changes that make learned skills become reflexive.

“Also key are periods of non-sleep deep rest where we're turning off our analysis of duration, path, and outcome, in particular for the thing that we were just trying to learn. And we're in this kind of liminal state where our attention is kind of drifting all over. It turns out that's very important for the consolidation, for the changes between the nerve cells that will allow what we were trying to learn to go from being deliberate and hard and stressful and a strain to easy and reflexive.”