Why do children want the same book read over and over and over again?

The many rewards of rereading were recently recalled in an article in the NYT: “Read it again, Sam.” http://www.nytimes.com/2011/12/04/books/review/read-it-again-sam.html
We remember our first encounter and reaction to a book, and at the same time, we are amazed to think that the book has somehow changed. The experience of rereading keeps you in the moment and also takes you back in time. But what is behind children wanting you to read them the same book over and over again? For children, rereading is not just a rewarding experience but essential for them to get ready to learn to read. The books children ask you to read over and over again—and yes, you think you can’t read that book one more time— helps them understand how narrative works and offers them comfort and familiarity with the story and the characters. They know the story, in fact they have most likely memorized the story and can “read it’ to you. This is one of the ways children get ready to learn to read. And the love affair they have for a particular book begins a lifetime of meeting books that become their lifelong companions. So yes, do read Danny and the Dinosaur once again, and again, and again.