Let's be honest, most of us do it, at least some of the time. We modify our own opinions in line with what other people think, especially our friends and peers.

A problem for psychologists investigating the effect of peer influence is that it can be tricky to tell whether people are simply acquiescing in public, for show, or if their attitudes really have changed. A new study by a team of psychologists at Harvard University has used an innovative mix of behavioural and brain-scan methods to show that peer influence really can change how people value something, in this case the attractiveness of a face.