I think the difficulty with this video is that it appears he is making the statement that you can’t tell when someone is lying when he is really saying that there is no one ‘giveaway’ that works for every liar, every time.

There are some general tendencies that a lot of people have when they are lying like not looking at you or looking at you too much, but those are also situational things.

Personally, rather than trying to pay hyper-attention to people’s body language, I just go with what my instincts say. I’ve been wrong sometimes, but I’ve been right more often.