I will know. I am the lie detector. Thus began each episode of Lie Detector, a strange cross between a relationship counseling session and an episode of the Jerry Springer Show that ran on British daytime television last year. A frequent topic of discussion was one guest's suspicion that his or her partner had been unfaithful. However much we may abhor it, deception comes naturally to all living things.
Birds do it by feigning injury to lead hungry predators away from nesting young.
Nature amply rewards successful deceivers by allowing them to survive long enough to mate and reproduce. But knowing how to catch deceit can be just as important a survival skill as knowing how to tell a lie and get away with it. A person able to spot falsehood quickly is unlikely to be swindled by an unscrupulous business associate or hoodwinked by a devious spouse. By closely observing facial expressions, body language and tone of voice, practically anyone can recognize the telltale signs of lying. In order to know what kind of lies work best, successful liars need to accurately assess other people's emotional states.