Detecting Witness Deception


Detecting Witness Deception

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By Brad Bradshaw, Ph.D., Bradshaw Litigation Consulting

Lie detection, although far from being an exact science, has come a long way over the past several years. The problem is that many of the ways liars reveal themselves is not easily identifiable in a court setting. For example, polygraphs (i.e., lie detectors) work because most people have a physiological response to lying. It is difficult to know that a person’s heart rate has increased or his hands have begun to sweat from looking at him across the room. Pupil dilation is also a potential indicator of dishonesty, but if you are close enough to see a change in the witness’s pupils you are invading that witness’s personal space. So in an experimental setting (i.e., research laboratory with polygraph machines) it may be possible to identify deceit from the physiological change. During a deposition, however, those methods are not a viable option.

So what other options are there? One possible predictor of deception in a non-laboratory setting is voice pitch. For many people, even during little white lies, the pitch of the voice gets higher. People also tend to talk more when lying because they feel the need to provide a lot of information in order to convince the listener. (Remember that the next time your kid misses his or her curfew.) They tend to sound rehearsed and repeat the same key phrases several times. That information may or may not be riddled with pauses, “ums,” etc., as the person is piecing the lie together.

The problem is that some people talk that way all of the time, so you must have a baseline for comparison before you can conclude that a person is lying. I am pretty good at detecting deceit in my friends because I am familiar with their behavior when I know they are telling the truth. If the first statement out of a juror’s mouth is a lie, it will be difficult to detect, especially if the lie is a simple omission (i.e., not telling the whole truth). Therefore, if you suspect a witness is lying about a particular portion of his testimony, you should stop asking questions about it. Move on to another line of questioning to see if his demeanor relaxes. Then return to the original subject to see if he gets anxious again. This will help you determine if the witness is nervous about that particular line of questioning or just nervous in general.

However, the single best predictor of deception is a quick, unconscious movement made by the person talking. That is, the person says “yes,” and shakes his head, indicating “no.” Or he says “no,” especially when denying something, but his head nods up and then down. Experts on lie detection have reviewed countless videos where a statement was later proven to be a lie (e.g., President Clinton denying a relationship with Monica Lewinski; Alex Rodriguez denying the use of steroids in his interview with Katie Couric) and the person’s head movement was one of the few consistent predictors of deception. Therefore, if you suspect a witness is not being honest during some particular aspect of his deposition, pay close attention to the movement of his head as he answers. Additionally, look for general inconsistencies in behavior. Does his body language match what he is saying? To a large extent, this is based on gut feeling and intuition, but we are all better at identifying when something is wrong, as opposed to what is wrong. So if you have a bad feeling about a witness, it should not be ignored.

The three keys to understanding body language are attention, intuition, and practice. You can practice by watching the body language of people you know well, when you know how they feel. Does what the person says match the way he says it? Pay attention to your own body language as well. What kind of things do you do naturally without thinking about it? Do you chew your nails? Is it because you are nervous about a lie you just told? Probably not. You are probably just bored. You must account for the context of the situation. Giving a deposition can be a scary experience for witnesses. That can make it is easy to misinterpret anxiety cause by an external factor (e.g., the stress of the moment) with anxiety caused by an internal factor (e.g., lying). So the next time a witness looks at you with his arms crossed, don’t rush to judgment. Sometimes witness cross their arms because it is a comfortable way to sit – not because they are being deceptive.

About the Author

Brad Bradshaw, Ph.D., is a litigation consultant based in Nashville, Tennessee. Dr. Bradshaw helps attorneys prepare for arbitration and trial, anywhere in the country. For more information please visit or call (615) 739-6553.

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