By asking someone basic, nonthreatening questions, you are able to observe a response baseline. Ask them about the weather, their plans for the weekend, or anything that would elicit a normal, comfortable response. When they respond, observe their body language and eye movement—you want to know how they act when they are telling the truth. Do they shift stance? Glance in one direction or the other? Or look you dead in the eye? Make sure you ask enough questions to observe a pattern.
Once you move from neutral territory to the “lie zone,” you should be able to observe a change in body language, facial expressions, eye movement, and sentence structure. Everyone will give different subconscious clues when telling a lie, which is why it’s important to observe a normal baseline prior to entering the lie zone.
Liars often pull their bodies inward when lying to make themselves feel smaller and less noticeable. Many people will become squirmy and sometimes conceal their hands to subconsciously hide fidgety fingers. You might also observe shoulder shrugging.
People will often give away a lie in their facial expressions, but some of these facial expressions are subtle and difficult to spot. Some people will change their facial coloration to a lighter shade of pink, others will flare their nostrils slightly, bite their lip, perspire slightly, or blink rapidly. Each of these changes in facial expression signifies an increase in brain activity as lying begins.
Often when a person is lying, they will slightly change the tone and cadence of their speech. They might start speaking more quickly or slowly, and with either a higher or lower tone. Often, the sentences they use become more complex as their brain works on overdrive to keep up with their tale.
People who are lying will also sometimes start removing themselves from their story and start directing the focus on other people. You will hear fewer me’s and I’s as liars try to psychologically distance themselves from the lie that they’re weaving.
Remember: Everyone has different “lying behavior” so there is no one guaranteed lie-detection method. It’s most important to be able to compare a liar's baseline behavior to the body movement, facial expressions, eye movement, and verbal cues that they use when they are telling a lie.
