What I see frequently is that people vehemently disagree in an emotional debate. After exchanging a few arguments everyone sticks to their original position and nothing seems to have changed.

However, when the topic gets brought up again a while later, they have shifted their position closer to mine, but also insist that they've always thought that.

I really wonder what is going on there, but I can see the aggregate opinion shifting by talking while nobody thinks they 'lost' the debate (for all those who identify far too strongly with their opinions.).