jokes to the left of me, jokes to the right of me...

Predisposed was a pretty good book about how pervasive the fundamental difference in mindset that produces liberals vs conservatives are - you can take the left/right spectrum 20 questions from the appendix via an online quiz I made a few days ago. Here are some interesting quotes from the book:
Across a range of topics, the mean responses of liberals consistently favored the new experience, the abstract, and the nonconforming. Conservatives just as consistently favored traditional experiences that were closer to reality and predictable patterns. Conservatives, for example, preferred their poems to rhyme and fiction that ended with a clear resolution. Liberals were more likely to write fiction and paint, or attend a music concert. Experimental, arrhythmic verse, amorphous story lines, and ambiguous endings just do not trip the triggers of many conservatives and, perhaps relatedly, they are less likely to be performers, a fact that is all too apparent from the announced political affiliations of comedians, rock stars, and Hollywood actors.
Young found that this individual tendency toward hard or soft categorization--the tendency to take what we see and divide it into clearly labeled and separated mental boxes or, alternatively, to opt regularly for the mental equivalent of a catchall kitchen drawer--turns out to be a pretty good predictor of political temperament. Liberals are more likely to be soft categorizers and conservatives hard categorizers.
From the conservative perspective, referring to a set of findings and claims as "just a theory" could hardly be more damning; it bespeaks an absence of certainty that is troubling, especially if someone is proposing big and expensive changes on what is taken to be little more than debatable conjecture. To liberals, theories, even if dissent is present and i's are left undotted and t's uncrossed, are much more valuable--the weight of current scientific evidence is likely good enough for them and future modifications to knowledge (look, a new bean!) are more likely to be taken in stride. "The great thing about science is not that it is right but that it can be wrong."
A common question we get when people learn that our research deals with the biological differences of liberals and conservatives is whether one ideology is "more evolved" than the other. Typically, liberals are eager to be told that conservatives are some type of antediluvian life form and conservatives are equally eager to learn that liberals are at odds with the natural order. Sorry to disappoint, but this type of question is silly.
The human nervous system is complicated 8 and includes sensory systems, which rely on specialized neurons to detect things like light, pressure, temperature, and motor systems, which make possible everything from locomotion to nose picking.
As Shankar Vedantam points outs, "no one intuits the presence of a neurotransmitter."
Liberals seemed more amused by, "I almost had a psychic girlfriend but she left me before we met," or "I planted some bird seed... a bird came up... now I don't know what to feed it," while conservatives preferred puns or jokes such as, "You know you're in trouble when at the control tower there's a note taped on the door that says 'back in 5 minutes.'"
I don't know about conservative joke (I feel like it would be funnier if it was on the cockpit door?) but that psychic girlfriend one is pretty good.