For a view of memory and literacy in mediaeval Europe, see Mary Carruthers' works. A fundamental skill at that time, for the scholarly, was the use of books to furnish one's mind with ideas to be called forth at will, and the living work held in one's head was, despite Socrates' gloomy prediction, still considered superior to the mere written text.

From a later time, here is Francis Bacon: Reading maketh a full man; conference a ready man; and writing an exact man.

Circumstances have changed, but the thread running through all of these still applies. Knowing only where to look things up is like trying to speak a language from a dictionary instead of learning the vocabulary.

Fixed your last link for you.