If smiles are so easy to fake, why do we trust them?

We are good at faking them but also equally as good at knowing when they are truly genuine. The physical motion of a smile is a straightforward, easy to fake, practice. And yet, it carries a heavy load of social cues and meanings. They tend to incite trust and cooperation, but sometimes they are also used for mischief and personal gain. However, as social psychologist Alexander Danvers explores, while they're physically easy to re-create, doing it convincingly is a far more complex endeavour than initially thought.