In social science PhDweebdom, we call emotion "affect" just to confuse budding grammarians who struggle with the difference between effect and affect. The relationships between cognition (stuff you know), affect (stuff you feel) and motivation (what moves ya to do something) are complex, baffling, and altogether enough to drive one crazy.
So, why bother?
In my continuing saga of studies I'd like to see, I would love to know what people "know" about Obama versus what they "feel" about him, and which better predicts support. I have no partisan issue here, but I suspect affect plays a bigger role in support than does cognition. I'm not suggesting Obama supporters don't think, I'm just wondering whether emotion is a key factor, overwhelming cognition. I suspect it is.
In general, other than party identification, key factors in who you vote for at the presidential level are competence and integrity. Some lean one way, some lean the other. And individual elections can frame the race around one versus the other. A good example is 1976 and Jimmy Carter, a post-Watergate election in which integrity became the main factor. How people decide these two is a fascinating issue, and it's my non-scholarly sense that Democrats seem to lean more on competence and Republicans seem to lean more on integrity -- but that's more of a gut feeling than one based on hard data.
A fun test would be asking Democrats where they stand on issues, using the NES traditional 7-point scale, and then asking them to place Obama and Clinton on the same scale, and see where they fall. There's a neat web site that kinda does this, asking you a lot of issue questions and then telling you who you should support, the candidate most fitting your stance.
Didn't work at all for me, at least at the moment. Clearly I'm not cognitive.