All Intensive Purposes

Cass Sunstein describes ideological amplication:

A few years ago, I was involved in some studies that uncovered a funny fact: When Republican-appointed judges sit on three-judge panels with other Republican appointees, they show unusually conservative voting patterns. So too, Democratic-appointed judges on three-judge panels show especially liberal voting patterns when sitting with fellow Democratic appointees. In short, like-minded judges show a pattern if "ideological amplification."

The presence of even one Republican appointee often makes Democratic appointees much more moderate. Republican appointees often become much more moderate when even a single Democratic appointee is there. . . .

It turns out that ideological amplification occurs in many domains. It helps to explain "political correctness" on college campuses--and within the Bush administration. In a recent study, we find that liberals in Colorado, after talking to one another, move significantly to the left on affirmative action, global warming, and civil unions for same-sex couples. On those same three issues, conservatives, after talking to each other, move significantly to the right. . . .

In the earlier days of the web, there was a lot of back-and-forth between different views. Now it seems that much more linking goes on to confirm rather than challenge what posters are saying.