Hi,
I would say that those first thoughts we have when reading anything would be where I would look first for any underlying assumptions or judgments. We are beings who create meaning, so it is natural for us to want to immediately find meaning when we begin reading anything. Out minds latch on to meaning, so to speak, but often that meaning, if not always, is surfaces through our own idiosyncratic filters, or ways of perceiving the world.
I would tell students to take notes as they read, to write down any potential assumptions they may have as they read. I think what we are talking about is mindful reading.
I believe Aristotle said, "It is the mark of an educated mind to be able to entertain a thought without accepting it."
Hope this is helpful.
John