People with extreme views tend to have more confidence that they are right, and as people gain confidence they become more extreme in their beliefs. By contrast, those who lack confidence and are unsure what they should think tend to moderate their views. Not knowing what to do, cautious people are likely to choose the midpoint between relevant extremes. But if other people seem to share your view, you are likely to become more confident that you are correct. As a result, you will probably take a more extreme position. ... What is especially noteworthy here is that this process—of increased confidence and increased extremism—might well be occurring simultaneously for all participants ... But those movements will be invisible to each participant. It will simply appear that others "really" hold their views without hesitation.

Cass R. Sunstein
Shiraz Abdullahi Gallab

Why Societies Need Dissent, 2003