All these aspect of lying should be noted and inserted to the actions of a character that is lying at the time. Afterall, writers should show not tell.
1. Lack of or too much eye contact
The biggest indicator someone is telling a lie is lack of or too much eye contact. It’s a common belief that when people lie they avoid eye contact and look elsewhere. While this is often true, some liars make too much eye contact just to make you believe they are speaking the truth.
2. Foot movement
When people lie they often exhibit signs of nervousness or anxiety. Foot movement is the biggest indicator of anxiety and nervousness. Liars often shake their legs or make regular leg movements to avoid tension and run away. This can be used as a clear-cut clue to catch a liar.
3. Shorter responses
This is a verbal clue displayed when people lie. When lying people often stay silent during the conversation or offer shorter responses. They also use more ums, ers, and ahs to fill in the gaps. If a person is making more speech errors it’s an indication of lack of truth.
4. Change in pitch
If you observe someone communicating in higher pitch than normal it can be a sign of lying. Some people also maintain lower than normal pitch. High or low pitch indicates there is something off.
5. Shoulder shrugs
People often shrug their shoulders when they don’t know or agree to something. If someone is shrugging while speaking it may indicate they don’t agree with what is coming out of their own mouth.
6. Too much sweating
Some sweat excessively when they lie. This abnormal sweating happens because of the adrenalin rush from anxiety and nervousness.
7. Changing the Subject
The thought process required to support a lie should be fast. Not everyone has fast thought processes so they change the subject to something completely different.
When people lie they often touch objects lying around to relieve stress. Some people might act as if they are more interested in the object than the conversation to avoid confrontation.
9. Face touching
Studies have found that when people lie, they often rub their nose. It’s a scientific observation, experts believe the adrenaline rush opens the capillaries of the nose making it itchy. Some people also cover their mouth and eyes while lying, this is an uncommon observation.
10. Excessive lip licking
Lying puts stress on our body and the biggest indicator of body stress is a dry mouth. In order to rectify the dry mouth, liars are often observed licking their lips often.
Unless the liar very staunchly believes in his/her lie, the above mentioned points should easily help you in spotting a liar.