Body language should be read through a scientific and unemotional eye, report researchers at the Harvard Business School. Whether in business or romance, many people use body language to convey false messages and to manipulate others. Cons are masters at recognizing the nonverbal communications of others and preying on the needs they perceive. It can be very useful to learn a few concepts about how to read body language lies.

Keep a close watch on the eyes. It is very difficult for a liar to look you straight in the eye. At the same time, pathological liars and those practiced in the art of lying may hold your eyes for longer than a few seconds to make you feel uncomfortable and unable to rely on your instincts.

Watch the hands of the person speaking. While keeping the hands held behind the back may be thought of as a power stance, it is more likely to mean the person is hiding something. Truthful people use open palms, while liars usually will keep their palms hidden in the pockets or turned over.

Consider how the person touches his face. Taekwondo instructors at TKD Tutor report that people often will cover their mouths when they are lying. They will place the thumb on their cheeks and splay two or more fingers across their mouths in an effort to "cover up" their lies. They may institute a fake cough to cover up the signal.

Be on guard around people who touch their faces in any form. Rubbing the nose often indicates the person is a skilled liar and is merely diverting his hand from his mouth on purpose. A person who rubs his eyes often is trying to avoid eye contact while lying.

Pay attention to nervous gestures that could give away a liar. No matter how accomplished liars are, they often develop twitches in their feet or legs. They may fidget with their clothing by picking at lint or straightening their pants leg. Slouching, shrugging and other gestures that are abnormal for the person also can be signs of an impending lie.