Being able to detect a liar is a skill that many people would like to have. It is useful for law enforcement and security agencies as well as |business owners and managers. Many different methods have been developed in the pursuit of the truth. You should find one or two of them useful if you want to know how to tell if someone is lying.

In the movie Liar, Liar, Jim Carrey's character goes from being a compulsive liar to being someone incapable of telling a lie. In the process, the film manages to show us how much lying has become a part of our daily lives. We all tell lies. One study suggests that the average person tells at least one lie a day.http://www.psychologytoday.com/articles/pto-19960901-000008.htm

As much as we might lie, few will admit that they want to be lied to. How can you tell if someone's lying? There's no 100% way to know for sure, but the following methods may help you start to distinguish the fibbers from the saints.

• Using a person's body language to determine if they are lying can be difficult because there is no universal set of behaviors that identifies deception.http://www.uplink.com.au/lawlibrary/Documents/Docs/Doc64.html Also, what can be an indicator of lying for some (such as rubbing one's nose) can be a nervous habit for others. It is possible to confuse nervousness as a lying response in some situations.http://www.time.com/time/magazine/article/0,9171,966891-1,00.html

• Liars often fidget. This occurs because the person's nervous system reacts to the lie, producing excess energy.http://www.uplink.com.au/lawlibrary/Documents/Docs/Doc64.html This excess energy can manifest itself in a number of ways:

1. Covering one's mouth or face. This often occurs when the liar feels bad or guilty for telling the lie.http://teenadvice.about.com/od/peerpressure/a/blliarliar.htm
2. Touching the nose. When we lie, the tissues in our nose engorge with blood and cause them to tingle or itch.http://www.entrepreneur.com/management/article185770.html
3. Nervous hand movements.http://www.bbc.co.uk/dna/h2g2/A664021 This includes wringing the hands together and rubbing, picking or playing with the fingers.
4. Defensive behaviors such as leaning backward and crossing the arms or legs. These act as a "barrier"for the person and reduces their anxiety levels.
5. Holding an object in front of the body as a sort of invisible barrier.http://www.marcandangel.com/2008/07/07/25-acts-of-body-language-to-avoid/
6. Rubbing the neck.http://www.entrepreneur.com/management/article185770.html
7. Rubbing the eyes. This indicates that the person doesn't believe or disagrees with a statement.http://www.entrepreneur.com/management/article185770.html
8. Shuffling the feet. http://bodyodd.msnbc.msn.com/archive/2008/02/13/663244.aspx
9. Clenched jaw. http://bodyodd.msnbc.msn.com/archive/2008/02/13/663244.aspx
10. Licking the lips.

• To avoid nervous gestures and fidgeting, liars might exhibit rigid posture or body movements.http://www.uplink.com.au/lawlibrary/Documents/Docs/Doc64.html This also might show up through a lack of gestures when talking.http://www.uplink.com.au/lawlibrary/Documents/Docs/Doc64.html Gestures used to illustrate speech, such as stabbing the air, declines when a person is lying.

• Most people believe that eye contact, or lack there of, is an indication if someone is lying to you. While this can be true, lack of eye contact can be a simple cultural difference. http://www.msnbc.msn.com/id/4072816/ Studies have shown that while introverts are less likely to make eye contact when lying, extroverts will actually increase their eye contact when lying to someone.http://www.uplink.com.au/lawlibrary/Documents/Docs/Doc64.html Also, because liars know that eye contact is usually an indicator of deception, they might over-correct and make constant eye contact.

• Facial expressions are another way of finding out if someone is lying. This can show up in several different ways:

1. Delayed expressions or ones that last longer than they naturally would. http://humanresources.about.com/od/selectemployees/a/nonverbal_com.htm
2. A prolonged smile or amazed look. Most natural expressions will fade after about four seconds.http://www.time.com/time/magazine/article/0,9171,966891-1,00.html
3. Crooked or asymmetrical facial expressions.http://www.time.com/time/magazine/article/0,9171,966891-1,00.htm
4. A fake smile will involve only the lips and mouth.http://www.marcandangel.com/2008/07/07/25-acts-of-body-language-to-avoid/

• Incongruent behaviors are when there is a mismatch between actions, words, tone of voice or expression. They are often a sign of deception. They might occur in one of the following ways:

1. Expressions do not match the person's statements.http://humanresources.about.com/od/selectemployees/a/nonverbal_com.htm
2. Words do not match the body language. A person might nod their head while saying, "No."http://www.entrepreneur.com/management/article185770.html
3. Mismatch between a person's expression and their tone of voice.http://www.bbc.co.uk/dna/h2g2/A664021
4. Body gestures and facial expressions are out of sync. One often occurs after the other.http://www.time.com/time/magazine/article/0,9171,966891-1,00.html
5. Misuse of a common gesture. Also called "leakage emblems," this type of misplaced gesture might include making the "okay" sign below the waist or shrugging one shoulder instead of two.http://www.uplink.com.au/lawlibrary/Documents/Docs/Doc64.html

• Microexpressions (also called microgestures) are expressions or gestures that last less than one-fifth of a second and typically display emotions the person is trying to disguise. http://www.apa.org/monitor/julaug04/detecting.html Microexpressions can take a variety of forms including voice shifts, head movement or facial expressions.http://www.uplink.com.au/lawlibrary/Documents/Docs/Doc64.html The Facial Action Coding System (FACS) designed in 1978 by Paul Ekman coded 46 different facial movements into 10,000 microexpressions. http://www.time.com/time/magazine/article/0,9171,1229109,00.html

1. It is almost impossible to control microexpressions.http://www.uplink.com.au/lawlibrary/Documents/Docs/Doc64.html
2. FACS has an accuracy rate of 76 percent.http://www.time.com/time/magazine/article/0,9171,1229109,00.html
3. If combined with voice and speech measures, FACS has an accuracy rate of up to 90 percent.http://www.apa.org/monitor/julaug04/detecting.html
4. Since it primarily depends on human analysts, it is impossible to standardize it.http://www.time.com/time/magazine/article/0,9171,1229109,00.html
5. A machine called "Silent Talker" has been created that is said to be able to detect microexpressions.http://ca.encarta.msn.com/encnet/features/columns/?

• A person's voice may subconsciously change when they are lying. This can be heard in two different ways:

1. Upward inflections. People naturally inflect the ends of questions upwards. Some people, however, may do this when making false statements. http://www.entrepreneur.com/management/article185770.html
2. Rise in pitch.http://www.psychologytoday.com/articles/pto-20051228-000007.html A person's voice will rise in pitch when they are angry, afraid, upset or lying about 70 percent of the time.

• Statement analysis is based on the idea that certain language patterns exist when people are lying versus when they are telling the truth.http://www.psychologytoday.com/articles/index.php?term=19970501-000033 The following is a list of things that liars will commonly do in their statements:

1. Use less first-person pronouns. A liar will try to distance him or herself from the lie by reducing their use of "I" and "me."http://www.apa.org/monitor/julaug04/detecting.html Instead they will often use third person pronouns such as "you," "we," "it," "they," "them" or even drop the pronoun altogether.http://www.msnbc.msn.com/id/4072816
2. Use the pronoun "that" as a distancing word. One of the best examples of this is Bill Clinton's infamous statement, "I did not have sexual relations with that woman, Miss Lewinsky."
3. Shift pronouns. A liar often shifts their pronoun use. For example, they might go from "we" to "they," say "my wife and I" instead of "we" or switch from saying "my car" to "the car."http://www.fbi.gov/publications/leb/1996/oct964.txt
4. Use more negative emotion words. Liars will use words such as hate, worthless and sad as if subconsciously expressing their guilt or anxiety.http://www.apa.org/monitor/julaug04/detecting.html
5. Use fewer exclusionary words. Liars have problems distinguishing between what they did and did not do and, as a result, will avoid using words such as except, but and nor. http://www.apa.org/monitor/julaug04/detecting.html
6. Use convincing statements such as "to tell you the truth" or "to be perfectly honest." http://www.msnbc.msn.com/id/4072816/
7. Use noncommittal phrases such as "I think," "I believe," "to the best of my knowledge" or "kind of."http://www.fbi.gov/publications/leb/1996/oct964.txt An analysis of Jeffery MacDonald's statement about what he claimed happened on the night his wife and two daughter were killed showed he used such phrases.http://www.statementanalysis.com/macdonald/ MacDonald was found later found guilty of the murders.
8. Use less cognitive words such as "understand" and "realize."http://www.psychologytoday.com/articles/pto-20051228-000007.html
9. Change or use the incorrect verb tenses.http://www.fbi.gov/publications/leb/1996/oct964.txt Liars will often shift verb tense when telling a lie or use the incorrect verb tense. Scott Peterson made this mistake] in a January 28 interview on Good Morning, America when he said, "I mean we took care of each other, very well. She was amazing." He promptly corrected himself and added, "She is amazing."http://www.statementanalysis.com/speterson/
10. Add extraneous information. Liars feel the need to convince you of their story and will often add extra information to their stories.
11. Change nouns to refer to the same thing. People have specific vocabularies. Any deviation from this vocabulary is a good indicator that their reality has shifted from the truth to a lie.http://www.fbi.gov/publications/leb/1996/oct964.txt
12. Mix up small details. Honest people have a clear picture of what happened and will be consistent with the smaller details. Without this mental image, liars will have trouble with minor things and will not be as consistent about them.http://teenadvice.about.com/od/peerpressure/a/blliarliar.htm
13. More likely to make passive statements. For example, they will say "I'm not guilty of the crime."http://sports.espn.go.com/mlb/news/story?id=3244344
14. Often request you to repeat your questions.http://www.msnbc.msn.com/id/4072816/ This gives them more time to consider their response.

• A polygraph machine measures a person's heart rate, blood pressure, breathing rate and electro-dermal activity (sweat) for changes.http://ca.encarta.msn.com/encnet/features/columns/?article=lyingmachines Any change in these factors is believed to indicate deception.

1. Research indicates that polygraph machines have an accuracy rate of 80 to 90 percent.http://www.guardian.co.uk/science/2007/sep/18/sciencenews.crime
2. Because popular opinion puts polygraph success rate at almost 100 percent, it works well as a deterrent to lying and often elicits confessions.http://www.guardian.co.uk/science/2007/sep/18/sciencenews.crime
3. False positives, or when a person tests positive for lying even though they are telling the truth are more common than false negatives.http://www.bbc.co.uk/dna/h2g2/A664021 This is because often an innocent person is afraid that their answers might be perceived as untruthful, and the machine is registering that fear.http://www.psychologytoday.com/articles/pto-20051228-000007.html
4. Although polygraphs can indicate when someone gets anxious, it cannot determine what is causing the anxiety.http://www.npr.org/templates/story/story.php?storyId=15670581
5. A 1998 Supreme Court ruling stated that blocking polygraph tests is constitutional because "here is simply no consensus that polygraph evidence is reliable."http://www.npr.org/templates/story/story.php?storyId=15670581

• Voice stress analysis uses computer programs designed to detect stress levels in a person's voice.http://www.fas.org/irp/news/1997/n19970923_971204.html People are usually nervous when they are lying, and the nerves cause their voice to tremble inaudibly under the stress.

1. Voice stress analysis is more cost effective and less obtrusive than a polygraph machine.http://www.govtech.com/gt/print_article.php?id=99712
2. Analysis does not have to be in person. It can be done over the phone or with a recording.http://query.nytimes.com/gst/fullpage.html?res=9A03E4DD1338F932A35754C0A9629C8B63
3. Voice stress analysis has been used by the British insurance industry since 2002.[http://www.guardian.co.uk/science/2007/sep/18/sciencenews.crime
4. Scientific research, including studies done by the U.S. Department of Defense, place its success rate at about 50 percent.http://www.guardian.co.uk/science/2007/sep/18/sciencenews.crime
5. Voice stress analysis machines can be used by the government for employment screening and by private security cases, but subjects must be aware that they are being used.http://query.nytimes.com/gst/fullpage.html?res=9A03E4DD1338F932A35754C0A9629C8B63
6. Voice stress analysis cannot be used in U.S. courts as evidence, but several states allow it to be used during criminal investigations.http://query.nytimes.com/gst/fullpage.html?res=9A03E4DD1338F932A35754C0A9629C8B63

• Truth serums are a common staple in many espionage movies, but reality does not match the fantasy. Currently, there is no drug that is either consistent or predictable as a way of getting someone to tell the truth.http://www.washingtonpost.com/wp-dyn/content/article/2006/11/19/AR2006111900891_pf.html Even the most famous of the truth serum drugs Thiopental Sodium (better known under its trademark of "Sodium Pentothal") does not make someone tell the truth. It simply puts the subject into a very relaxed state. This makes them more open to suggestion and reduces their inhibitions, meaning there is a higher chance that they will say what they are thinking.http://www.bbc.co.uk/dna/h2g2/A664021

• As you go on your own quest to find the truth amidst the lies, remember some advice that FACS creator and psychologist Paul Ekman uses when trying to detect the truth, You must use lying as a last interpretation and rule out everything else that's possible.http://www.apa.org/monitor/julaug04/detecting.html If you go looking for lies, you are more likely to find them, even if they don't exist. If you keep a neutral point-of-view, you're more likely to uncover the truth—even if it's lies you're looking for.