I think that’s a reason why they might choose not to change their minds, but often it seems that they don’t even think about it enough to get to that point. It’s not so much “I may be wrong, but I still want to get along with my friends who agree with me” as it is “I don’t know why you’re wrong… but I’ve decided that you still are.” The difference is that, even if they don’t have any groups anchoring them to it, people still hold tightly to their opinion.