New research shows that "liberals" don't understand "conservatives" as well as "conservatives" understand "liberals". (I use quotes because the labels aren't my preferred way to characterize the viewpoints.) It's interesting to note how uncharitable the leftists are. These results line up pretty well with my observations of people in the wild.
One other point that I find really interesting and important about Haidt's work is his findings on the ability of different groups to empathize across these ideological divides. So in his book (p. 287) Haidt reports on the following experiment: after determining whether someone is liberal or conservative, he then has each person answer the standard battery of questions as if he were the opposite ideology. So, he would ask a liberal to answer the questions as if he were a "typical conservative" and vice-versa. What he finds is quite striking: "The results were clear and consistent. Moderates and conservatives were most accurate in their predictions, whether they were pretending to be liberals or conservatives. Liberals were the least accurate, especially those who describe themselves as 'very liberal.' The biggest errors in the whole study came when liberals answered the Care and Fairness questions while pretending to be conservatives." In other words, moderates and conservatives can understand the liberal worldview and liberals are unable to relate to the conservative worldview, especially when it comes to questions of care and fairness.
In short, Haidt's research suggests that many liberals really do believe that conservatives are heartless bastards-or as a friend of mine once remarked, "Conservatives think that liberals are good people with bad ideas, whereas liberals think conservatives are bad people"-and very liberal people think that especially strongly. Haidt suggests that there is some truth to this.
James Taranto adds:
But there's a limitation to Haidt's experiments. Because his methodology is new, it has only been applied in the contemporary political context. Perhaps in a few decades it will be possible to determine the extent to which Haidt's findings reflect timeless truths about human nature as opposed to peculiarities of the present day. As time travel is a logical impossibility, Haidt cannot go back in time and gather data from earlier generations.
Obviously we're all always traveling through time, but we're limited to one direction: into the future.