Low-level white noise, played at a low volume without headphones, can put the brain into an optimal state for learning and workflow.

“it turns out that white noise, which is essentially all frequencies of sound, or all frequencies of sound that we can perceive, mixed up kind of randomly, there's no structure to it, turned on at a low volume, not with headphones most of the time, puts the brain into a state that's optimal for learning and workflow.”