We all engage in meaning making. Scholars from widely different fields have widely different approaches to the question of how people make sense of their social and political world. Most of us use some form of heuristics, rules-of-thumb, shortcuts, schemata, chronically accessible constructs, and a host of other theoretical fictions to help us tame the information tide (to borrow a book title). I'm sure there are others I've missed, but they all share in common the idea that we can't possibly cope with the world in all its complexity, so we find shortcuts to help us make sense of what we see and hear (and taste, and smell, and feel, if I want to be fair to all the senses).
These are more than mere shortcuts -- they come rich with meaning. We impress meaning on what we see and hear and then fit it to our own expectations and predispositions. Doesn't fit? Oh, we'll make it fit, we'll get that round peg into a square hole even if we have to change what we actually heard or saw. Selective attention, meet selective memory.
Why am I going on about this? In part because I've been reading student papers from my Public Opinion graduate seminar, in part because I've been reading the "who hates the most, liberals or conservatives?" nonsense on the web and papers, and in part because I needed blog material for today.
But it comes down to this: What people know, unfortunately, is often a function of what they want to know, or what they want it to mean.