A large body of political scientists and political psychologists now concur that liberals and conservatives disagree about politics in part because they are different people at the level of personality, psychology and even traits like physiology and genetics.
That’s a big deal. It challenges everything that we thought we knew about politics — upending the idea that we get our beliefs solely from our upbringing, from our friends and families, from our personal economic interests, and calling into question the notion that in politics, we can really change (most of us, anyway).
It is a “virtually inescapable conclusion” that the “cognitive-motivational styles of leftists and rightists are quite different.”
The occasion of this revelation is a paper by John Hibbing of the University of Nebraska and his colleagues, arguing that political conservatives have a “negativity bias,” meaning that they are physiologically more attuned to negative (threatening, disgusting) stimuli in their environments. (The paper can be read for free here.)