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How to Spot a Liar: Identifying Deceptive Behavior

Dec 01, 20059 mins
Investigation and Forensics

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

We’re used to seeing interrogation scenes on TV—the bare lightbulb, the sweaty, hostile detective, you know the drill. But how do investigations play out in the corporate world, when the questioner wears a suit rather than a gun holster, and the chilling environs of a police room are replaced by the bland layout of a corporate office? Here are four things to know about conducting interviews and interrogations that yield results.

Know What You’re Stepping Into

An interview and an interrogation serve very different purposes, so treat them differently.

In an interview, the questioner is still gathering information. The investigation is ongoing. In an interrogation (like the made-for-TV vignette above), an investigator believes he already knows what the subject did. The goal is to get a confession or a confirmation about what happened from the subject himself.

Mixing interviewing with interrogation is a common mistake even among seasoned law enforcement professionals, says Nathan Gordon, coauthor of Effective Interviewing and Interrogation Techniques, who trains police and security officers on interviewing skills as director of the Academy for Scientific Investigative Training in Philadelphia.

During an interview, the investigator asks questions but lets the subject do most of the talking. An interview should last no more than 20 or 30 minutes, the length of the average person’s keen attention span. The mood should be nonaccusatory. “Once you become accusatory in an interview, you have biased everything you are collecting. And when you ask informational questions in an interrogation, you’re saying that you don’t know whether that person did it,” says Gordon. “You’re looking at a disaster.”

An interrogation on the other hand goes as long as is necessary. You do 95 percent of the talking, presenting your evidence and coaxing a confession from the subject. To be successful, you have to recognize the battle going on within a guilty subject and use it to your advantage. Subjects are torn between the desire to relieve their conscience by confessing and the fear of punishment. If you take a nonthreatening approach, you can diminish a subject’s fear of punishment and increase his desire to confess. “My concept of an interrogation is that I know you did it and I’m here to help you,” Gordon says. “I don’t believe in yelling, screaming or threatening.”

Watch What They Say—and How They Say It

It’s a given that most employees who are brought into an investigative interview are going to be nervous, whether or not they have done something wrong. (Remember, they have also seen the cop shows on TV, and may have expectations—or if they have something to hide, seek to avert attention from themselves.) Asking simple questions like name, address, marital status, schooling and so on gives you a chance to analyze the subject’s truthful behavior in this heightened state and establish your own authority. You should also take this opportunity to create some rapport with the subject and make a little conversation. Maybe you both went to the same school or live in the same town. “People who are alike, like,” says Gordon. If you can get the subject to relax early on it will make any stressful or deceptive behavior she exhibits later all the more clear.

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.

Gordon breaks physical behaviors down into three categories: emblems, illustrators and adaptors. An emblem is a nonverbal response that expresses a person’s complete feelings with no words required. For example, when asked how he feels about being interviewed, the subject puts a hand to his face and scratches his nose with the middle finger extended. He may not be conscious of the message he has sent, but the raised middle finger means the same thing here that it means when he does it on the highway at rush hour. “Emblems are very accurate to a person’s true feelings,” says Gordon.

Illustrators and adaptors are nonverbal responses that accompany a verbal response. Illustrators enhance the listener’s ability to understand the meaning of the verbal message. Adaptors distract from it. When a subject puts his hand on his heart and says, “I didn’t do it!” that physical gesture reinforces his statement. Illustrators are generally a sign of honesty. If that same subject professed his innocence while wiping his hand over his mouth, that would be an example of an adaptor. This physical response makes his verbal message harder to understand. In this case, this would be a sign of deception.

By observing a subject’s body language during an interview, you can glean quite a bit of information. Truthful people tend to present an open posture, while deceptive people will cross their arms defensively or stretch out their legs to increase the distance between them and you. A subject who gestures away from her body while speaking may be subconsciously trying to distract you from herself as the topic of conversation. Stressed people often pat themselves on the leg or stroke their own arm for tactile comfort. The crossing and uncrossing of legs can be a sign of discomfort. Yawning also can signal a person’s stress as the fight-or-flight response kicks in and a nervous subject’s body requires more oxygen. (A yawn can also mean fatigue, or convey a defensive posture, the way a lion bares its teeth when threatened.)

It’s also important to be aware of how cultural differences can affect a subjects physical gestures and their interpretation. Gordon points out that a lack of eye contact, or changes in eye contact, are generally interpreted as a sign of deception in U.S. business culture. But in the Hispanic community, for example, it is considered disrespectful to stare in the eyes of a superior.

Finally, you have to be aware of your own body posture during an interview. People will often subconsciously mimic the body posture of a superior to curry favor—putting their hands in their pockets or crossing their arms when their boss does because they want to project that “I’m like you.” Make sure you present an open body posture during the interview. This does two things. First, it prevents a subject from accidentally mimicking a defensive posture. Second, if a subject deviates from truthful posturing to a deceptive posture, it makes that change more meaningful.

Pick the Right Setting

The location of the encounter can also contribute greatly to its success. Again, it’s important to know what kind of question-and-answer session is appropriate. Interrogations should always take place in your office, never at a subject’s home or office where he feels more secure and is less apt to confess to wrongdoing. The location of an interview, on the other hand, may vary. Here are some more tips for designing an appropriate interview space:

  • The room should be nonthreatening and not too small. Gordon suggests a 9-by-9 space.
  • The room should contain a desk, a few chairs and bland artwork.
  • There should be nothing on the wall that the subject will face.
  • Two chairs should be set up with nothing between them so that the subject has no physical barrier to reduce stress and so you can view the subjects entire body language.
  • The chairs should be a social distance apart (3 to 4 feet) for an interview. For an interrogation, use chairs on casters so that you can move into the subjects personal space.
  • Your chair should be higher than the subject’s chair to create a sense of superiority.

Also, if you have others in the interview room—whether its a subjects supervisor, or a representative from legal or HR—have those people sit quietly behind the interview subject so as not to be a distraction, says Gordon.