Unconscious Learning

There is no evidence that significant learning can occur if you are not consciously aware of the process. Thus, learning while in deep sleep is not possible. Learning when you are barely asleep is possible, but it isn't very efficient because it's difficult to avoid waking up or falling into deep sleep. In any case, learning during light sleep only works for simple facts and the facts must be reinforced while awake.

Some studies show that you remember less if you study shortly after waking up, so it might be a good idea to give yourself some extra time in the morning before doing any memory-intensive tasks. Other studies show that people can remember information better if they go to sleep immediately after studying it. Perhaps this is because the mind continues to process the information during sleep.

Additionally, numerous studies have shown that you cannot remember material if it is presented in a subliminal manner. So, subliminal learning and subliminal advertising is not effective. When it comes down to it, there is no shortcut to learning the old fashioned way.