Derren Brown likes to look into your past. Here he is demonstrating his technique anonymously on the street trying to peer into people's minds. Some claim that this is a sham that he either paid people are that he's like a fortune teller and he's "fishing" Which is basically saying generalities that can relate to a lot of people. But if I'm correct he's doing some NLP trick, which is looking at the eye and seeing how it reacts, when it looks N,S,E,W it corresponds to a certain feeling in their brain thus he's able to tell what kind of emotions his words bring and thus deduce what might be the case with them.There's not a lot of clips of his clown trick so it probably doesn't work as often as he likes.