From an interesting article in the Times by Patricia Cohen: "For anyone who assumes political choices rest on a rational analysis of issues and self-interest, the notion that preference for a candidate springs from the same source as the choice of a color scheme can be disturbing. But social psychologists assume that all beliefs, including political ones, partly arise from an individual’s deep psychological fears and needs: for stability, order and belonging, or for rebellion and novelty.
These needs and worries vary in degree, develop in childhood and probably have a temperamental and a genetic component, said Arie Kruglanski of the University of Maryland. A study of twins, for instance, has shown that a conservative or progressive orientation can be inherited, while a decades-long study has found that personality traits associated with liberalism or conservatism later in life show up in preschoolers.
No one is arguing that an embrace of universal national health care or tax cuts arises because of a chromosome or the unconscious residue from a schoolyard spat. What Mr. Jost and Mr. Kruglanski say is that years of research show that liberals and conservatives consistently match one of two personality types. Those who enjoy bending rules and embracing new experiences tend to turn left; those who value tradition and are more cautious about change tend to end up on the right. What’s more, these traits are reflected in musical taste, hobbies and décor..."
Such a hypothesis is ripe for partisan bickering, as each side plays the I'm-better-than-you game, but I think the observation does jibe with my personal experience. I don't think you can say the conservative worldview is "better" or "worse" than the liberal worldview, but it is clear that people gravitate to one or the other based on more that rational choices. Personality, culture, environment, and inclination do play significant roles.