From a letter written by Annie Sullivan, and reprinted in The Story of My Life by Helen Keller:

"[Mr. Thayer] asked me how I had taught Helen adjectives and the names of abstract ideas like goodness and happiness.  ... Why, it is as easy to teach the name of an idea, if it is clearly formulated in the child's mind, as to teach the name of an object. It would indeed be a herculean task to teach the words if the ideas did not already exist in the child's mind.  If his experiences and observations hadn't led him to the concepts, small, large, good, bad, sweet, sour, he would have nothing to attach the word-tags to.  ...

"If you give a child something sweet, and he wags his tongue and smacks his lips and looks pleased, he has a very definite sensation; and if, every time he has this experience, he hears the word sweet, or has it spelled into his hand, he will quickly adopt this arbitrary sign for his sensation.  ... It is not the word, but the capacity to experience the sensation that counts in his educations."

This quote makes sense.  Every new concept I encounter, I feel I only understand if I can relate it to something concrete I've experienced or to a concept that I've understood before. 

Bloom's Taxonomy describes the steps involved in deeper learning.  Applying knowledge to real situations, indeed seems to solidify my understanding of concepts.