How to detect a liar

It is important to clear up a big myth: there’s no universal sign of lying. Many people believe that liars always do things like touch their face, rub their nose, or fidget, but that’s simply not true. There isn’t a one-size-fits-all behavior that reveals whether someone is being honest or deceitful.

It all comes down to detecting changes in behavior. The key is to observe how someone typically acts while answering honestly and see if that behavior is consistent all the time. It's all about detecting patterns and deviations.

Exposing a liar comes down to detecting changes in behavior

For example, if someone doesn't rub their nose when they talk, then starts nose-rubbing for one particular question, that break in pattern might be a red flag. The introduction or absence of the gesture could be a clue.

Understanding this principle is crucial. It's the foundation of detecting deception. That being said, there are behaviors that give stronger signals than others—signals that can only be interpreted in the context of a liar. In this guide, I will introduce you to some of these suspicious behaviors to help you spot liars more easily.

Long Pauses

Longer-than-usual pauses in speech or delays in answering a question may suggest lying. This often happens when a liar is unprepared for a question and needs time to formulate a coherent response. Though speaking slowly may indicate lying, it is certainly not conclusive evidence by itself. Some people are naturally slow speakers.

Change in Pitch

A person's voice tends to be higher when they are anxious or afraid, and this may occur during attempts to deceive

The pitch of the voice denotes emotion. A person's voice tends to be higher when they are anxious or afraid, and this may occur during attempts to deceive. Mumbling and fumbling indicate stress, which could be caused by lying. However, there are other causes of stress apart from lying that produce changes in pitch, so again, be cautious with this one.

Lack of Details

Stories with vague details are a common trait among liars, especially when they are not very imaginative or accustomed to lying. Their concern is that any particular detail may be shown to be fabricated. Liars avoid giving specific information out of fear that their stories may not remain consistent. They also worry that they might not recall exactly what they lied about, so they tend to give as few details as possible to avoid having to remember.

A technique used by some interrogators when they believe they have been told a lie is to carry on the conversation for a while and then repeat the same question a bit later. This puts the liar in a critical situation because now they have to rapidly recall exactly what they said before.

Sudden Physiological Changes

These changes are usually provoked by embarrassment or a sense of shame

These include blushing, sweating, blinking, pupil dilation, increased swallowing, or changes in breathing. These changes are usually provoked by embarrassment or a sense of shame or guilt. In this context, lip biting may also suggest some kind of tension—as though the person is trying to hold back the truth.

Lack of Emotions

The absence of distress signs or emotions specific to the situation may indicate that the events told are not true

Consider a person casually recounting a traumatic or horrifying experience with a nonchalant tone and demeanor—would that behavior classify as normal? The absence of distress signs or emotions specific to the situation may indicate that the events told are not true.

It must be noted that some people don't display guilt or tense emotions because they don't feel any. They simply don't believe that they did something wrong or that others have the right to know what happened.