• 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.Law Library: The Detection of Deception Via Non-Verbal Deception Cues Also, what can be an indicator of lying for some, such as rubbing one's nose, can be a nervous habit for others.TIME: The Fine Art of Catching Liars (April 22, 1985)

• Liars often fidget. This occurs because the person's nervous system reacts to the lie, producing excess energy.Law Library: The Detection of Deception Via Non-Verbal Deception Cues This excess energy can manifest itself in a number of ways:

1. Covering one's mouth or face.Law Library: The Detection of Deception Via Non-Verbal Deception Cues This often occurs when the liar feels bad or guilty for telling the lie.About.com: Liar, Liar How Can You Tell?
2. Touching the nose. When we lie, the tissues in our nose engorge with blood and cause them to tingle or itch.Entrepreneur.com: Are They Lying to You?
3. Nervous hand movements. This includes wringing the hands together and rubbing, picking or playing with the fingers.BBC: Detecting Lies
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.Law Library: The Detection of Deception Via Non-Verbal Deception Cues
5. Holding an object in front of the body as a sort of invisible barrier.Marc and Angel Hack Life: 25 Acts of Body Language to Avoid (July 7, 2008)
6. Rubbing the neck.Entrepreneur.com: Are They Lying to You?
7. Rubbing the eyes. This indicates that the person doesn't believe or disagrees with a statement.Entrepreneur.com: Are They Lying to You?
8. Shuffling the feet.MSNBC.com: Roger Clemens licks his lips. But does that mean he's lying? (February 13, 2008)
9. Clenched jaw.MSNBC.com: Roger Clemens licks his lips. But does that mean he's lying? (February 13, 2008)
10. Licking the lips.MSNBC.com: Roger Clemens licks his lips. But does that mean he's lying? (February 13, 2008)

• To avoid nervous gestures and fidgeting, liars might exhibit rigid posture or body movements.Law Library: The Detection of Deception Via Non-Verbal Deception Cues This also might show up through a lack of gestures when talking.Law Library: The Detection of Deception Via Non-Verbal Deception Cues 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.MSNBC.com: Why People Lie — and How to Tell if They Are (January 31, 2004) 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.Law Library: The Detection of Deception Via Non-Verbal Deception Cues Also, because liars know that eye contact is usually an indicator of deception, they might over-correct and make constant eye contact.BBC: Detecting Lies

• 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.About.com: Believe What You See
2. A prolonged smile or amazed look. Most natural expressions will fade after about four seconds.TIME: The Fine Art of Catching Liars (April 22, 1985)
3. Crooked or asymmetrical facial expressions.TIME: The Fine Art of Catching Liars (April 22, 1985)
4. Fake smile. A fake smile will involve only the lips and mouth.Marc and Angel Hack Life: 25 Acts of Body Language to Avoid (July 7, 2008)

• 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.About.com: Believe What You See
2. Words do not match the body language. A person might nod their head while saying, "No."Entrepreneur.com: Are They Lying to You?
3. Mismatch between a person's expression and their tone of voice.BBC: Detecting Lies
4. Body gestures and facial expressions are out of sync. One often occurs after the other.TIME: The Fine Art of Catching Liars (April 22, 1985)
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.Law Library: The Detection of Deception Via Non-Verbal Deception Cues

• • For more information, check out Mahalo's How to Read Body Language.

• ExpertVillage: How to Tell if Someone is Lying with Body Language (Time: 2:35)

• 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.APA Online: Detecting deception (July/August 2004) Microexpressions can take a variety of forms including voice shifts, head movement or facial expressions.Law Library: The Detection of Deception Via Non-Verbal Deception Cues The Facial Action Coding System (FACS) designed in 1978 by Paul Ekman coded 46 different facial movements into 10,000 microexpressions.TIME: How to Spot a Liar (August 20, 2006)

1. It is almost impossible to control microexpressions.Law Library: The Detection of Deception Via Non-Verbal Deception Cues
2. FACS has an accuracy rate of 76 percent.TIME: How to Spot a Liar (August 20, 2006)
3. If combined with voice and speech measures, FACS has an accuracy rate of up to 90 percent.APA Online: Detecting deception (July/August 2004)
4. Since it primarily depends on human analysts, it is impossible to standardize it.TIME: How to Spot a Liar (August 20, 2006)
5. A machine called "Silent Talker" has been created that is said to be able to detect microexpressions.MSN Encarta: How Can You Tell If Someone Is Lying? Part III

• YouTube: Paul Eckman: Why We Lie (Time: 1:46)

• 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.Entrepreneur.com: Are They Lying to You?
2. Rise in pitch.Psychology Today: Spotting the Liar

(January/February 2006) A person's voice will rise in pitch when they are angry, afraid, upset or lying about 70 percent of the time.TIME: The Fine Art of Catching Liars (April 22, 1985)

• Statement analysis is based on the idea that certain language patterns exist when people are lying versus when they are telling the truth.Psychology Today: Spotting the Liar (January/February 2006) 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."APA Online: Detecting deception (July/August 2004) Instead they will often use third person pronouns such as "you," "we," "it," "they," "them" or even drop the pronoun altogether.MSNBC.com: Why People Lie — and How to Tell if They Are (January 31, 2004) FBI.gov: Statement Analysis: What Do Suspects' Words Really Reveal?
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."ESPN: Body Language Analyst Breaks Down Clemens, McNamee Performances
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."National Association of Investigative Specialists Statement Analysis: New Investigative Processes to Help You Uncover The Truth FBI.gov: Statement Analysis: What Do Suspects' Words Really Reveal?
4. Use more negative emotion words. Liars will use words such as hate, worthless and sad as if subconsciously expressing their guilt or anxiety.APA Online: Detecting deception (July/August 2004)
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.APA Online: Detecting deception (July/August 2004)
6. Use convincing statements such as "to tell you the truth" or "to be perfectly honest."MSNBC.com: Why People Lie — and How to Tell if They Are (January 31, 2004)
7. Use noncommittal phrases such as "I think," "I believe," "to the best of my knowledge" or "kind of."FBI.gov: Statement Analysis: What Do Suspects' Words Really Reveal? 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 29 such phrases.Statement Analysis: Jeffrey MacDonald MacDonald was found later found guilty of the murders.
8. Use less cognitive words such as "understand" and "realize."Psychology Today: Spotting the Liar (January/February 2006)
9. Change or use the incorrect verb tenses.FBI.gov: Statement Analysis: What Do Suspects' Words Really Reveal? 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."Statement Analysis: Scott Peterson Case
10. Add extraneous information. Liars feel the need to convince you of their story and will often add extra information to their stories.FBI.gov: Statement Analysis: What Do Suspects' Words Really Reveal?
11. Change nouns to refer to the same thing.FBI.gov: Statement Analysis: What Do Suspects' Words Really Reveal? People have specific vocabularies. Any deviation from this vocabulary is a good indicator that their reality has shifted from the truth to a lie.FBI.gov: Statement Analysis: What Do Suspects' Words Really Reveal?
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.About.com: Can You Spot a Liar?
13. More likely to make passive statements. For example, they will say "I'm not guilty of the crime."ESPN:

Body Language Analyst Breaks Down Clemens, McNamee Performances

1. Often request you to repeat your questions.MSNBC.com: Why People Lie — and How to Tell if They Are (January 31, 2004) This gives them more time to consider their response.

• YouTube: How to Detect Lies (Time: 4:19)

• A polygraph machine measures a person's heart rate, blood pressure, breathing rate and electro-dermal activity (sweat) for changes.MSN Encarta: How Can You Tell If Someone Is Lying? Part III 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.Guardian Unlimited: Testing Times (September 18, 2007)
2. Because popular opinion puts polygraph success rate at almost 100 percent, it works well as a deterrent to lying and often elicits confessions.Guardian Unlimited: Testing Times (September 18, 2007)
3. False positives, or when a person tests positive for lying even though they are telling the truth are more common than false negatives.BBC: Detecting Lies This is because often an innocent person is afraid that their answers might be perceived as untruthful, and the machine is registering that fear.Psychology Today: Spotting the Liar (January/February 2006)
4. Although polygraphs can indicate when someone gets anxious, it cannot determine what is causing the anxiety.NPR: Foolproof Test for Catching Liars Still Elusive
5. A 1998 Supreme Court ruling stated that blocking polygraph tests is constitutional because "there is simply no consensus that polygraph evidence is reliable."NPR: Foolproof Test for Catching Liars Still Elusive

• YouTube: Michael Shermer Tests the Polygraph and Lie Detection Part 1 (Time: 8:23)

• Voice stress analysis uses computer programs designed to detect stress levels in a person's voice.Federation of American Scientists: Voice Stress Analysis Evaluation Begins (September 23, 1997) People are usually nervous when they are lying, and the nerves cause their voice to tremble inaudibly under the stress.Guardian Unlimited: Testing Times (September 18, 2007)

1. Voice stress analysis is more cost effective and less obtrusive than a polygraph machine.Government Technology: Good Science or Just Bunk? (June 7, 2006) International Society of Voice Stress Analysts: The Truth about Voice Stress Analysis / Polygraph Controversy
2. Analysis does not have to be in person. It can be done over the phone or with a recording.The New York Times: It's the Way You Say It, Truth Be Told
3. Voice stress analysis has been used by the British insurance industry since 2002.Guardian Unlimited: Testing Times (September 18, 2007)
4. Scientific research, including studies done by the U.S. Department of Defense, place its success rate at about 50 percent.Government Technology: Good Science or Just Bunk? (June 7, 2006) Guardian Unlimited: Testing Times (September 18, 2007)
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.The New York Times: It's the Way You Say It, Truth Be Told
6. Voice stress analysis cannot be used in U.S. courts as evidence, but several states allow it to be used during criminal investigations.The New York Times: It's the Way You Say It, Truth Be Told

• YouTube: ABC News Report on Voice Stress Analysis (Time: 6:47)

• 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.The Washington Post: Some Believe 'Truth Serums' Will Come Back (November 20, 2006) 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.BBC: Detecting Lies

• 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."APA Online: Detecting deception (July/August 2004) 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.