Here's the latest from Jonathan Haidt of "moral foundations" fame. He was part of a team that asked about 2,000 people to rate how they felt a "typical" liberal or conservative integrated five moral dimensions into their worldview. There are real differences: "Liberals endorse the individual-focused moral concerns of compassion and fairness more than conservatives do, and conservatives endorse the group-focused moral concerns of ingroup loyalty, respect for authorities and traditions, and physical/spiritual purity more than liberals do."
That's reality, but what do people think? Answer: they substantially exaggerate the moral differences between liberals and conservatives. In fact, they exaggerate the extremity of moral concerns for both their own group and the other group. And there's bad news for us lefties: as the chart on the right shows, we were the biggest exaggerators. Apparently conservatives know us better than we know them.
Why? One possibility is that the study is wrong. Its sample was light on extreme conservatives, and that might have made a difference even after the researchers corrected for it. A second possibility is that liberals are over-influenced by Fox News and Rush Limbaugh. We take them as representative of conservatives even though they represent only its right wing. A third possibility is that the conservative leadership in Washington DC is more hardnosed than the movement as a whole, and everyone legitimately takes that as representing real-world conservatism. And finally, a fourth possibility is simply that liberals are wrong. We interact very little with conservative institutions (churches, business groups, etc.) and therefore don't understand them, while conservatives have no choice but to interact with liberal institutions (Hollywood, academia, etc.).
You may leave other possibilities in comments.