THE BLOG
04/12/2013 02:26 pm ET Updated Jun 12, 2013

How to Tell When Your Child Is Lying

How do you know when your child or teen is telling you the truth? Being able to decipher truth from fiction is incredibly important for parents.

After studying human lie-detection and then implementing the principles while working with thousands of teens, parents and families, I wanted to give a few pointers for adults, teachers and parents.

The clues below are some of the statistical signs of deceit -- meaning they most often show up in people who are lying. Lie detection and body language is a complex science, but I have simplified it here for immediate application. If you want to dig deeper into the science, I lay out the entire method in my book, Human Lie Detection and Body Language 101.

The most important thing to remember about lie detection is that one clue alone does not guarantee lying -- if you see some of the clues listed below, it is simply a red flag to get more information.

1. Verbal Nuance

If the timing is off between gestures and words, lying or hidden emotions are most likely lurking. For example, if your teenager is talking about how angry they are about something, but their facial expression is one of sadness or neutrality, they are most likely forcing the emotion even though they do not feel it. Verbal nuance can also show up as a delayed reaction to the emotion. They might say, "Yeah, I am angry about it," pause and then display an angry expression. This is not genuine emotion because their words are not matching their expressions.

2. Relief

A liar almost always shows great relief when the subject is changed. If you are talking to your teen about an issue you are suspicious of and then move on from the topic, notice their reaction. If they show great relief or a total change in behavior, they were most likely tense or hiding something.

3. Fear vs. Surprise

In my presentations and articles on nonverbal behavior, I often reference microexpressions. A microexpression is a brief, involuntary facial expression that is shown on the face of humans according to the emotions that are being experienced. Unlike regular prolonged facial expressions, it is difficult to fake a microexpression. They often occur as fast as 1/15 to 1/25 of a second. There are seven universal microexpressions: disgust, anger, fear, sadness, happiness, surprise and contempt. In terms of lying, I believe that fear and surprise are the most important ones for parents to recognize. After all, if you ask your child, "Did you know about the cheating incident at school?" A fearful microexpression will tell you something very different than if they look surprised.

Surprise:

  • The brows are raised and curved
  • Skin below the brow is stretched
  • Horizontal wrinkles across the forehead
  • Eyelids are opened, white of the eye showing above and below
  • Jaw drops open and teeth are parted but there is not tension or stretching of the mouth
Fear:
  • Brows are raised and drawn together, usually in a flat line
  • Wrinkles in the forehead are in the center between the brows, not across
  • Upper eyelid is raised, but the lower lid is tense and drawn up
  • Upper eye has white showing, but not the lower white
  • Mouth is open and lips are slightly tensed or stretched and drawn back

4. Verbal Clues

If you are speaking with your child and they begin responding to an accusation by offering a belief in general instead of the specific instance (i.e. 'Do you smoke pot?' 'I believe pot is dangerous') they are subconsciously avoiding answering the question. They also might add in additional details until you believe them to fill silences. Liars often use phrases like "to tell you the truth," "to be perfectly honest," and "why would I lie to you?" Another clue to deceit is when teenagers have answers that sound extremely rehearsed, even if it is about a casual event.

Lying is a very natural, yet dangerous occurrence. Unfortunately it is part of growing up, but parents need to be aware of teens lying habits to keep them safe. I share these tips and hope they will be used in the right circumstance.

To find out more about Vanessa's work, visit: ScienceofPeople.org.

Her nonverbal behavior book: Human Lie Detection and Body Language 101

Her parenting book: Do I Get My Allowance Before or After I'm Grounded

References:
Paul Ekman (1999). Basic Emotions. In T. Dalgleish and M. Power (Eds.). Handbook of Cognition and Emotion. Sussex, U.K.: John Wiley & Sons, Ltd.
"The lie detective: San Francisco psychologist has made a science of reading facial expressions" by Julian Guthrie, San Francisco Chronicle, Monday, September 16, 2002.
Book: Why Kids Lie: How Parents Can Encourage Truthfulness