You may have heard of sleep tapes that offer effortless learning during sleep. Your investment in such tapes will not be money well spent.

Learning during sleep should be discouraged! It is possible to occasionally recall a fraction of the material presented during sleep (probably only then when it enters your brain during short periods of transition from REM to temporary waking).

Whatever you might gain from your sleep tapes will by far be offset by damage to the quality of sleep. They can also shorten REM sleep.

Interestingly, memories acquired minutes before falling asleep do not get consolidated! Even a few minutes of sleep leave a short window of waking time with a complete memory erasure.

Luckily, we rarely learn mission-critical information shortly before dozing off.