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How to Spot a Liar: Identifying Deceptive Behavior

Spotting a liar requires a good read on visual clues, but cross-examination and critical thinking are even better

Gordon developed the Forensic Assessment Interview and Integrated Interrogation Technique, or Faint, a test composed of approximately 30 questions that can fit almost any investigative interview. The format gives interviewers the chance to analyze a subjects verbal and nonverbal responses for truthful or deceptive behavior.

As you progress further into the interview, start asking more projective questions, like "What is this interview and investigation about?" and "When the person who did this is caught, what do you think should happen to him or her?" These questions allow you to analyze common verbal cues so that you can be alert for signs of deceptive behavior.

Truthful people are usually more helpful and talkative and will try to narrow the investigation. For example, suppose a large sum of money goes missing from an employee's desk. During interviews, two employees are asked who they think took the money.

Employee 1 says, "Several of us had the opportunity, including me, I guess. Betty is the only person who couldnt have done it; she was out sick."

Employee 2 says, "I didn't see anything, but anyone could have taken it, even someone from outside the department. I was with Tom all day, so it couldnt have been me."

The second employees response has some common earmarks of deceptive behavior. A person seeking to mislead a questioner often claims to have no information and will try to broaden the investigation to create as many subjects as possible, Gordon says. Truthful people will often admit that they had the opportunity but will exclude others whom they know to be innocent. Deceptive people often make broad statements to exclude themselves from suspicion, but rarely exclude others.

Your demeanor as an interviewer influences the outcome. If the interviewer seems competent, a truthful person will become less nervous as his fear of being wrongly accused dissipates. In that same situation, a guilty person becomes increasingly nervous as his fear of being correctly identified as the culprit increases. When asked what should happen to the culprit, a truthful person will often make a strong decisive response: "He should be fired, required to repay the money and serve time in jail." A deceptive person usually responds in vaguer terms: "Well that's not up to me. It depends on why he did it."

Watch What They Do

A subjects physical behavior during an interview can also provide you with a great deal of information. The nonthreatening questions that you used to open the interview are critical because they give you a chance to make a baseline observation of a subject's physical demeanor and record any changes that take place as the questions get more sensitive.