What the Heck is Pluralistic Ignorance?

Here is an excerpt from the Economist's View, but the entire post is worth a read:

... many Americans think that what they see in the major political media reflects what most other Americans really think – when actually it often doesn’t.

Psychologists coined the term “pluralistic ignorance” in the 1930s to refer to this type of misperception... A study back then had surprisingly found that most kids in an all-white fraternity were privately in favor of admitting black members, though most assumed, wrongly, that their personal views were greatly in the minority. Natural temerity made each individual assume that he was the lone oddball. ...