And I'd venture a guess that the typical person in Cambridge is more prejudiced than the typical American. But I hadn't seen an experiment demonstrating an overt prejudice in "tolerant" people until today.
Read about the study here.
Now here's the rub. Suppose you live in Cambridge with the kind of people they found in the study. Do you point this out to them and hope that being conscious of their prejudice will make them a little more tolerant or is the truth not good enough? I'm not sure. I'm inclined to think the later. (Edited: 3/9/12)