20 Ways to Spot a Liar

How can you tell when someone is lying to you? According to YouGov, 49% percent of people admit to lying to their significant other. Thankfully, PI UK offers services to help with allegations of dishonesty. Before you decide whether you need our lie detection services, look at some of the ways you can identify when someone is lying to you.

Body Language Gives a Lot Away

People give away a lot with nonverbal communication. Unconscious movements and facial expressions can indicate what someone is thinking and feeling.

Lying causes stress and discomfort. When we look for bodily signs of lying, we’re looking for signs that someone is uncomfortable. Here are some examples of body language that are commonly associated with lying:

Avoiding Eye Contact/ Blinking A Lot

If someone is lying to you, they’ll seem unable to look at you. They might also start blinking a lot because they’re uncertain about where to fix their gaze.



If someone is lying to you, they’ll seem unable to look at you. They might also start blinking a lot because they’re uncertain about where to fix their gaze.

Shaking or Trembling

If someone is nervous about a lie, they’ll get a rush of adrenaline that causes their body to shake. You might be able to see this if they can’t hold an object still, or you might hear their voice trembling.

Excessive Face Touching

Sometimes, adrenaline causes a liar’s face to itch. If someone keeps scratching or touching their face, their body might be responding to the discomfort of lying.

Pursing Lips

To combat dry mouth, a liar automatically purses the lips to try and reintroduce moisture.


The rush of adrenaline that comes with a lie can cause an increase in blood flow, which makes the face look red.

Inappropriate Nodding or Head Shaking

When someone nods while making a negative statement or shakes their head while making a positive statement, it can signify that what they’re thinking doesn’t correspond with what they’re saying.

Verbal Clues

When someone is lying, their speech is altered in several ways. Here are some verbal signs to look out for:

Vague Language

If someone is using vague language, it can indicate that they’re being untruthful.

Example: You ask your partner, “Where have you been?” and they respond with “I was at a pub with a friend,” rather than “I was at The Dog and Duck with Michael.”

Unnecessary Details

A liar might also add many irrelevant details around their vague response to make it look like they’re speaking precisely.

Example: “I left work and got in the car. I drove into town, and I put £3.50 in the parking metre so that I could park for two hours. I went into the bookshop for half an hour, and then I went to a pub with a friend.”

Repeating the Question

Liars often need a few seconds to come up with something believable. Repeating the question they have just been asked gives them a way to make this pause look natural.

Example: “Where have I been? Well, I’ve been to the cinema.”

Not Answering Questions

If someone doesn’t answer a question, it can also indicate that they’re lying. They might change the subject or flounder and say nothing. They could also give you a response that sounds like they’re answering your question but doesn’t actually give you any information.

Example: You ask your partner, “Where have you been?” and they say, “I’ve been with Michael.”


Eventually, even the most experienced liars can let something genuine slip out. Slips usually happen when the liar is in the flow of conversation and has stopped paying attention to their lies.

Example: “I was at the pub with Michael- I mean Jen!”

Broken or Panicked Speech

Someone who is lying might start sentences without finishing them and jump around from one subject to another.

Changes in Pitch and Speed of Speech

Liars sometimes speak in an unusually high or low pitch. They can also start talking faster to try and get the discomfort of lying over with as soon as possible.

Changes in Volume or Tone of Voice

A liar might get defensive and start shouting or whisper because they are not confident in the lie.

Behavioural Signs

Repeated patterns of lying will cause a behaviour change. Here are some behaviours to look out for:


If someone has lied a lot about something, they will avoid certain places or people because they aren’t sure they can keep up with their lies. They might also have been found out and don’t want to see people who know about their lying.

Keeping Acquaintances Apart

A liar can become inconsistent over time. Often, they will go to great pains to keep one social group from interacting with another. They will get upset and try to interfere if their partner befriends a colleague or if a friend starts spending time with a family member.

Inconsistent Stories

If someone tells you a story more than once, you might find that details have changed. It’s normal for people to remember things differently from time to time. Still, if you realise that necessary details have changed, it is a red flag for lying.


Most liars feel shame and guilt about their dishonesty. These feelings can cause them to grow distant and cold towards you. They might lose interest in social activities and seem quiet.

Lie Detection

If you’ve spotted some of the signs of lying in a loved one, you should consider asking them to do a lie detector test. It is the most accurate way to spot a liar and the best way for you to get peace of mind.

Lie detection involves two essential parts: a polygraph machine and a trained human interpreter. A liar has some significant bodily responses that correspond with a state of stress, impatience, and arousal. Still, they are difficult to spot without equipment. The main thing that a polygraph machine does is measure these subtle reactions.


During a lie detector test, the interpreter asks simple questions, and the polygraph machine records how much someone is sweating, breathing, and how their heart is beating. When a subject is speaking, a sudden change in these factors indicates an untruthful answer.

Private Investigations UK offers private lie detector tests to businesses and members of the public. For more information please call 0800 002 0898

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