The psychological differences between liberals and conservatives.

Psychology Today: The Ideological Animal:

"...Most people are surprised to learn that there are real, stable differences in personality between conservatives and liberals—not just different views or values, but underlying differences in temperament. Psychologists John Jost of New York University, Dana Carney of Harvard, and Sam Gosling of the University of Texas have demonstrated that conservatives and liberals boast markedly different home and office decor. Liberals are messier than conservatives, their rooms have more clutter and more color, and they tend to have more travel documents, maps of other countries, and flags from around the world. Conservatives are neater, and their rooms are cleaner, better organized, more brightly lit, and more conventional. Liberals have more books, and their books cover a greater variety of topics. And that's just a start. Multiple studies find that liberals are more optimistic. Conservatives are more likely to be religious. Liberals are more likely to like classical music and jazz, conservatives, country music. Liberals are more likely to enjoy abstract art. Conservative men are more likely than liberal men to prefer conventional forms of entertainment like TV and talk radio. Liberal men like romantic comedies more than conservative men. Liberal women are more likely than conservative women to enjoy books, poetry, writing in a diary, acting, and playing...

...In 1969, Berkeley professors Jack and Jeanne Block embarked on a study of childhood personality, asking nursery school teachers to rate children's temperaments. They weren't even thinking about political orientation.

Twenty years later, they decided to compare the subjects' childhood personalities with their political preferences as adults. They found arresting patterns. As kids, liberals had developed close relationships with peers and were rated by their teachers as self-reliant, energetic, impulsive, and resilient. People who were conservative at age 23 had been described by their teachers as easily victimized, easily offended, indecisive, fearful, rigid, inhibited, and vulnerable at age 3. The reason for the difference, the Blocks hypothesized, was that insecure kids most needed the reassurance of tradition and authority, and they found it in conservative politics.

The most comprehensive review of personality and political orientation to date is a 2003 meta-analysis of 88 prior studies involving 22,000 participants. The researchers—John Jost of NYU, Arie Kruglanski of the University of Maryland, and Jack Glaser and Frank Sulloway of Berkeley—found that conservatives have a greater desire to reach a decision quickly and stick to it, and are higher on conscientiousness, which includes neatness, orderliness, duty, and rule-following. Liberals are higher on openness, which includes intellectual curiosity, excitement-seeking, novelty, creativity for its own sake, and a craving for stimulation like travel, color, art, music, and literature."