Obama and the Bradley Effect

Obama seems to have done worse in New Hampshire than the polls predicted. One explanation is the Bradley effect under which voters "have told the pollsters one thing about voting for a black man, but in the privacy of the voting booth, something else happens."

Without having any evidence, I suspect that the Bradley effect is most pronounced among recent college graduates. College students have to be very careful about what they say on issues of race else they be accused of racism. I suspect that many students get in the habit of hiding their views when talking to people who are not close friends. It may, therefore, be very natural for them to automatically tell pollsters that they are supporting a minority candidate even when they don't intend on voting for that candidate.