12. They can't seem to remember the details
People who lie often rely on a pre-developed script to make their deception believable, and when forced to deviate from this mental recording, they have trouble adapting and cannot keep up. This is why liars frequently forget the details of their story when pressed for more information. According to Dr. Susan Whitbourne, Professor Emerita of Psychological and Brain Sciences at the University of Massachusetts Amherst, “People telling the truth don’t have that much trouble remembering a true event, situation, or occurrence… Liars, however, will give themselves the ‘excuse’ of having a poor memory when, in reality, it’s only the lies they’re having trouble recalling.” In fact, they will often “recall” unrelated details or contradict themselves because they did not truly live the events they’re asserting to be factual.
A good way to catch someone in a lie is to ask them to tell their story in reverse. This will force the person to think more and thus make them more likely to slip up or reveal physical cues of their deception.