Comprehension or understanding makes it a whole lot easier to remember and recall the passage. When one understands what is being said, one can also summarize and put into one's own words the gist of the idea.
I like this..
Sometimes I use a similar way to show the same thing..
take any english sentence.. atleast 10 or so words.
eg. "Over the past three days, since I started learning Bach's Prelude in E Minor, I have already memorized the first half of the piece!"
then totally jumble it
days started I since Bach's E have first of memorized minor the already half piece (and so on for all the words)
read each sentence once through.. which one do you remember?
it also highlights the necessity for small chunks, the jumbled sentence is not that hard to memorise if you do it in 4 word groups, - the normal sentence is extremely easy to remember when done in small groups.
Its also easier to remember the regular sentence in small groups that are whole phrases -
1. Over the past three days
2. Since I started learning Bach's Prelude in E Minor
3. I have already memorized the first half of the piece!
This can perhaps be related to understanding whole chord progressions, or recognising melodic structure and development of a theme.