How To Catch A Liar
There's no such thing as a "tell." For example, when people look up, fidget or stutter they might just be nervous, and not exactly lying. However, because we rely on the truth to make our culture go round, it might make our lives easier if we could just spot a liar out of the crowd.
As it turns out you can tell if people are telling the truth or not, but it takes some skill, time and knowledge.