Children may tell lies for any number of reasons, depending on their age. Young children with active imaginations may tell lies because they are used to fantasy and don't clearly distinguish between imagination and reality. Older children and adolescents may lie for self-serving purposes, such as to get out of chores or cover up their activities with friends. If you pay careful attention to your child's behavior, it will help you tell if your child is lying.
Look at the child's facial expression. Children who are telling the truth have relaxed faces that usually show an emotion that matches what the child is saying. If a child is lying, however, his face may show anxiety caused by knowing that he is telling a lie.
Listen carefully to what the child is saying. Stories that are false may contain inconsistencies or elements that don't make sense. The story or parts of it may not sound believable. If you suspect a child is lying, ask the child to repeat what she just told you. Truthful stories told twice in a row will generally be the same, but stories that contain lies may change dramatically or contain accounts that cannot both be true.
Decide whether the child's story sounds rehearsed or spontaneous. Children who are telling the truth will usually tell it "off the cuff." The story will sound like a fresh recounting of an actual event. A lie, on the other hand, may sound stilted or rehearsed. Some children may even repeat the exact same phrases when telling a rehearsed story the second time.
Watch your child's body language. A child who is lying is more likely to appear nervous, defensive or scared. Look for hunched shoulders, a stiff body or face, repeatedly touching the nose or mouth and avoiding eye contact. While some children are anxious when speaking to adults no matter what they say, children who can speak comfortably to adults normally, but who are nervous when telling a particular story, may be lying.