I hate stuff like this. The article is about generalizations made from a group of people. If you apply that to a single person (to "catch a liar"), you will only sometimes be correct. Catching a liar is something that you should only do when you know you are correct, and all lie detection schemes cannot do that. Sort of like our system of justice which would rather a guilty person go free that convict an innocent person. Well, in theory at least.