This is interesting and would be easy for people to implement. Combine listening to specific playlist while studying and then listening to it on a loop while sleeping. I have to say I did not understand this part as it seems to be saying they had a concious agreement to alter unconcious behavior but maybe Im misunderstanding:

“After the researchers presented the puzzle soundtracks, they observed participants performing previously agreed-upon physical cues, such as sniffing in and out to indicate that they had heard the song and were programming their minds to search for a solution.”