lie detector

How to Detect Lies (Part 1)

It’s crucial that you understand your characters; if you don’t know them like the back of your hand, how can your readers hope to? Part of your job is to make them relatable and flawed. (Some types of writing supersede this, such as those which include allegorical figures, but that’s a technicality.) It’s a very natural thing for humans (and other biological beings) to not tell the truth. Sometimes, dishonesty itself can be the crux of a novel. It’s easy to make your character tell a lie, but how easy is it to convince the other characters, or your readers? 

This is just a basic run down of physical (body language) gestures and verbal cues that may indicate someone is being untruthful.


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Artificial intelligence lie detector

Wrongly accused and imprisoned for a crime you didn’t commit. It sounds like the plot to a generic crime thriller. However, this scenario does happen from time to time in the UK. From the Birmingham Six, falsely imprisoned for sixteen years, to the more recent case of Barri White, who was wrongly jailed for the murder of his girlfriend Rachel Manning, these situations can seem to the public like a tragic miscarriage of the criminal justice system.

However, what if you could stop these miscarriages of justice from happening? Imperial alumnus Dr James O’Shea, who graduated with a Bachelor of Science in Chemistry in 1976, has built a lie detector device called the ‘Silent Talker’ that he believes could help to improve criminal investigations.

While lie detector tests of any sort are not currently admissible evidence in British courts, Dr O’Shea believes Silent Talker could be an invaluable tool in helping law enforcement to focus their investigations.

Dr O’Shea says: “An original member of my team who helped to develop the Silent Talker was very close to the area where one of the attacks by Yorkshire Ripper took place. She took an interest in the case and found that the Ripper had been interviewed and passed over several times by the police. If the police had Silent Talker back then, it may have helped them to determine that they needed to spend a little more time on this guy, and investigate his background more closely.”

Artificially intelligent

The Silent Talker consists of a digital video camera that is hooked up to a computer. It runs a series of programs called artificial neural networks. These are computational models that take their design from animals’ central nervous systems, acting like an autonomous ‘brain’ for the device.

The computer programming in the artificial brain is a type of artificial intelligence called machine learning. It enables Silent Talker to learn and recognise patterns in data so that it can constantly adapt and reprogram itself during an interview. This enables Silent Talker to build up an overall profile of the subject to identify when someone is lying or telling the truth.

But how does it know when someone is lying? The inventors of the device claim it’s written all over your face. The camera records the subject in an interview and the artificial brain identifies non-verbal ‘micro-gestures’ on people’s faces. These are unconscious responses that Silent Talker picks up on to determine if the interviewee is lying.

Examples of micro-gestures include signs of stress, mental strain and what psychologists call ‘duping delight’. This refers to the unconscious flash of a smile at the pleasure and thrill of getting away with telling a lie. Dr O’Shea says these ‘tells’ are extremely fine-grained and exceedingly difficult for the interviewee to have any control over.

Coming to an interview near you

Dr O’Shea says the uses for such a device are numerous.

“One can imagine a near-future scenario in which your prospective employers are wearing Google Glasses, where every micro-gesture that ‘leaks’ from your face is a response that flashes by their eyes as ‘true’ or ‘false’ in real-time.”

While it does use the latest in computational techniques, Dr O’Shea says Silent Talker is not infallible. In tests to classify the micro-gestures as deceptive or non-deceptive, the Silent Talker has achieved an accuracy rate of 87 per cent.

However, this has not stopped prospective clients from clamouring for the device. Dr O’Shea and his colleagues have already been approached by security services about whether Silent Talker could be used to determine if people approaching a military checkpoint could be suicide bombers so that they can be eliminated before blowing up their target. The team’s answer has been a loud and emphatic ‘no’.

“In an ethical sense, such decisions should not be taken by a machine,” says Dr O’Shea.

Lie Detection

Bear with me, guys. This is going to be a rather long post- and even with its length, I still won’t be able to cover the whole concept of detecting lies.

To become a human lie detector, you have to incorporate a lot of things. Eye movements and body language are the biggest factors in determining whether or not a person is trying to deceive you. You have to be really observant, so it’s no wonder that only 1 out of 300 people naturally possess the incredible ability to sniff out lies.

So, let’s start with body language. Before you can tell the difference between a person being honest and a person being deceitful, you have to get to know the person.  Watch out of your peripheral vision as the person is talking. You may notice a few quirks, things that people do when they’re nervous or excited. For example, someone might bite his nails when he is about to tell a lie. Someone might get sweaty and jittery as she is thinking about running away from the situation. Figure out if the person is open to talking to you, or if they are closed off and cold.

“Open” body language includes moving closer, leaning forward, and relaxing their arms at their sides. If someone is being open towards you talking to them, they “feel” open. On the other hand, “closed” body language includes crossing their arms, keeping their distance, and fiddling with keys or a loose thread on their clothes. If people could put up actual shields when they didn’t want to talk to someone, they would. Since we can’t do that, however, our instincts compensate by telling us to shield ourselves with our arms and keep a safe distance away from threats.

Stressed body language also indicates that a person isn’t comfortable talking to you. Stressed body language includes irregular breathing, a wrinkled forehead, twitchiness, and flushing.  Blood pressure increases when we lie. Pulse rate quickens. If you can find a reasonable explanation for holding someone’s wrist, you could check their pulse. If not, blushing is a result of elevated blood pressure and therefore makes a good replacement for awkward pulse-checking. Body temperature changes (both too hot and too cold) are signs of deception, so if someone needs a glass of water, asks if the air conditioning is on, or needs to put on their jacket, you know something is up.

People also tend to “hunch in” when they’re lying because they want to blend in with the crowd. If someone is trying to make themselves look smaller and less obvious, trying to fit in with the background, that’s a sign they’ve got something to hide.

Right, then. Eye movements. Everyone’s heard the “If they can’t look you in the eyes, they’re lying” rule of thumb before. Yeah, that one’s pretty much a myth. Since everyone’s heard it, dishonest people will purposely look directly into your eyes so that they seem more honest. In my experience, honest people are more likely to glance away and let their eyes wander a bit. That’s probably because they’re not too worried about being assessed for lies, so they’re allowing themselves to be curious and carefree.

When people lie, they get excited. This leads to rapid eye movements such as frequent blinking. Squinting is also a form of deception. When faced with an interrogator, some people feel as if staring directly into their eyes will open up the window to their soul and therefore allow the interrogator access to their deepest secrets. To counteract that, they squint, thinking it’ll close off the “window.”

Now, this next part is simply a generalized guideline. It is by no means the rulebook for every liar. Use this only as a basis to start with, and tailor what you know to the individual for the best results. Let’s say you asked someone a question. “What did you see that day?” The man looks to his left (your right, if you’re facing him) and then answers, “I didn’t see much. Just barely caught a glance of the girl.” Looking to his left is an indication of lying- generally. This means that the man really did see something important, but he doesn’t want to tell you. Looking to his left means he was trying to create a false image in his mind. Looking to his right, on the other hand, would have meant he was accessing a real memory, something he really saw that day. This method also applies to things the man could’ve heard and things the man could’ve felt.

Remember what I just said about tailoring to the individual. Before you jump straight into the questions, establish the baseline. Ask the questions you know the true answers to. “What date were you born?” “How old are you?” “What is your mother’s maiden name?” “Which high school did you attend?” Since you know the answers, watch their eye movements as they answer. When they answered honestly, where did their eyes look? To the left, or to the right? If they lied at all, which way did they look?

Now, for the difference between visual, auditory, and kinesthetic. Looking up indicates visual. Looking to the middle indicates auditory. Looking down indicates kinesthetic. If a woman looks down and to her left, she could be trying to remember how she felt when an event happened. Or, if her baseline works the other way, she could be trying to construct how she SHOULD have felt when the event occurred.  The same goes for auditory. If a woman looks to the middle left, she could be trying to remember what she heard last week, or she could be thinking of what she wants to tell the interrogator she heard last week. One side indicates an honest memory; the other side indicates a constructed memory. Make sure to ask the right questions so you can establish a good baseline. It wouldn’t do for you to think someone’s lying just because you got middle left mixed up with upward right or something like that.

I leave you all with this: Combine all the tips here into one package. Don’t work using only eye movements or only body language. That way leads to disaster.