Ah, he has answered my call for further exploration into this business of reading, so I direct you to Steve Ersinghaus at The Great Lettuce Head with his series on his thoughts as a writer, reader, and instructor of literature.
Steve starts by comparing the literary journey of reading to a physical traveling, exploring in a walk or taking a well-established route in a drive. Some of each is automatic, learned and not needed to actively call up to direct one’s path. But there is more information all around as we move onward to a destination, whether it be home, or work, or the end of a story.
I have just recently learned how to read for story (the reason to read fiction, after all) while acutely aware of voice, technique, character development, imagery, etc.; all the elements critical to writing. But I as yet have to learn how to pick up on the metaphors, symbolism, meaning, theme, etc. concurrently with the other two acts of reading. This will take skill and practice.