Teaching someone to recognize a lie includes the process of recognizing the truth. Recognizing a lie involves extra layers of complexity in my opinion. It's not easy. For example, there are thousands of salesmen who are pushing "get rich quick" books. How do you know who's lying? Is it the guy who sounds like a scumbag? No, that guy could very well be telling the truth. You don't know who's lying unless you already understand fully the subject matter at hand. In other words, you must first know the truth or at least the proper steps to get to the truth.