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10 expert techniques to tell if someone is lying

Left: A close up of a man's fingers strapped into a polygraph test, right, a wide photograph of a man undertaking a lie detector test
Image Credit (Left): standret / Freepik | Image Credit (Middle and Right):

You’re being lied to all the time. It’s not a nice thing to think about, but it’s true. On any given day people will attempt to deceive you 10 or 20 times. And chances are, you’ll tell your fair share of porky pies too.

It’s just human nature. According to research, 60% of folk can’t go 10 minutes without lying at least once. Mostly they’ll be little white lies, but sometimes people will be dishonest to you for their own gain. With that in mind, it could well pay to be able to see through the wool that people try to pull over your eyes.

Using research and techniques carried out by some of the world’s foremost law enforcement agencies, let’s delve into the world of lies and explore some methods to uncover the yarn-spinners.

1. Establish a rapport and then a baseline

Unless you’re on some sort of military operation and using extraordinary rendition and aggressive interrogation on a subject, you’ll want to opt for the ‘good cop’ routine, rather than the ‘bad cop’ one.

Cold, confrontational, and accusatory questioning will generally end most polite conversations. Even if there’s some sort of hierarchical set-up. Build a rapport with the person and they’ll relax around you. That’s the state you want them in. Empathy encourages openness.

Once the person is relaxed, talk about something they’re unlikely to lie about. Then observe their behaviour. You’re paying attention to how they sit and move and speak. Everything about them in their ‘truthful state’. This is your baseline. It’s a poker game. Once they start lying you can look out for their tells.

2. Avoid being swayed by signs of nerves

If someone feels the need to lie to you and you’re gearing up to catch them at it, chances are that you’re having a fairly serious conversation. As such, it can be expected that the person will be nervous to some degree. Whether they’re practicing deception or being totally honest with you.

You need to be careful that you aren’t reading into signs of stress, anxiety, or nerves too much. Non-verbal communication and microexpressions can indicate dishonesty, but just be careful not to mistake nerves for lying. It’s a subtle art that may take a while to master.

3. Are you being provided with too many details?

Liars are conscious that being too reticent with information can look suspicious. To counteract this they will often attempt to appear as open as possible by bombarding the person they’re talking to with unnecessary - often unverifiable - details.

4. Pay attention to smile authenticity

Fake a smile for the camera and it’s kind of obvious in the picture, isn’t it? That’s because false grins are generally just people manipulating the muscles around their mouths and nothing else. ‘Real smiles’ involve the whole face, with cheeks bunching up and wrinkles appearing around the eyes.

A truthful person will have no real desire or need to falsify a smile. Whereas a liar would. So look for that ‘whole face smile’.

5. Avoid contradicting or ‘tripping up’ the person

To determine if someone is lying you want them relaxed and liable to trip up. Spotting a liar isn’t a game where you’re awarded points for pointing out discrepancies. Be patient, and act as if you fully believe the story you’re being told.

6. Ask follow-up questions when you sense a specific lie

Now you’ll want to be subtle here with this technique but when you get the impression a lie has just been told, press them on it. As innocently as possible. Probe away and see if the person becomes uncomfortable or seeks to reroute the conversation.

When you sense a weak spot, move on. But surprise them by returning to the subject later. Use the element of surprise as a tool. Ideally, you want to be catching the liar in the act. That way it’s not an accusation, you’ve proven their deceit.

7. Beware toadying

Who doesn’t like a compliment? If your subject is being overly nice and laughing at all your minor jokes and being unusually friendly, by all means, enjoy it. But at the same time, be suspicious.

Also, look out for someone seeming too keen to agree with you. Add this to the forced laughing and overall crawling feeling and it’s a heavy hint of inauthenticity.

8. Listen out for repetition

Repeating words and phrases serves two purposes to the liar. Firstly, it’s effectively dead time that allows them to think - it’s stalling. Secondly, there’s a mantra-like quality to such verbal repetition. Not only does reiterating the same set of words make it stick in their mind, but it will also likely stick in the mind of the person they’re lying to.

Repetition is a red flag, red flag, red flag.

9. Ask for the story to be told backwards

A common tactic for liars is to create their mistruths in advance and practice them. More often than not this will be done via a narrative told in chronological order. Memorised enough, the teller can become very slick at repeating their story, sometimes with such panache and effort that the tale becomes almost like a memory.

You need to disrupt the story. Ask them to cut straight to the middle or end. Have them tell it backwards, maybe. Interrupt their usual flow of storytelling. An honest person should have little to no trouble skipping along the timeline of events. A liar is likely to flounder unless they are particularly adept at verbal deception.

10. It’s all in the eyes

Finally, perhaps the most important tip for anyone attempting to become a human polygraph… remember that the eyes are the window to the soul.

There is a common misconception about the relationship between someone who is lying and their eye contact. Most people would tell you that if a person avoids looking you in the eye when talking, it indicates dishonesty. This isn't always the case.

There may be any number of reasons for someone not to look at you while talking. However, seasoned liars are usually aware of the common assumption about eye contact and will often try to overcompensate. They’ll try to convince you of their straight talking by making sure to stare deep into your soul.

If you’ve established your baseline well, you may pick up on this increase in eye contact. They’re likely lying to you. And you’ve spotted it.