"Repetitio est mater studiorum."
"Repetition is the mother of studies/learning."
In you schooling career you must have heard this phrase many times over. Repetition is not the mother of learning; it is the mother of 'conditioning'. (Dog trainers call it 'drilling'.)
What is conditioning? It is the process of linking a condition to a result.
The typical example is Pavlov's experiment: shortly before giving food to a dog a bell was rung. After this was repeated several times, the dog began salivating at the bell ring, even if he wasn't given food.
The dog has been conditioned: its dog-mind connected the bell ring with food.
'Memorization' is a complex variant of conditioning; a context of conditions evokes a chain-reaction of conditioned responses in one's mind.
Although useful in many day-to-day situations and also in situations which require extremely quick and predetermined responses (e.g. close combat), conditioning and memorization have little to offer in conscious learning processes - in fact they hinder it.
'Forgetting' is a process of moving information from the conscious mind to the subconscious. This way, matters of conditioning, memorization and huge data crunching can be left to the subconscious while the conscious mind can focus on whatever is at hand with clarity.
If you fill your conscious (and subconscious) mind with junk through useless conditioning and memorization, they obstruct the flow of your thinking processes - your mind becomes slow, inflexible and predictable.
You just made a nice box to close your mind in.
If you want to be an efficient learner, don't memorize. Be extremely careful with conditioning thrust upon you, and actively inspect the processes of your mind to reveal such conditioning.
The quickness of mind comes from being able to create/unfold structures from axioms and also to fold them back again to minimum.
You take the diamonds found this way and integrate them into yourself.