A Look Inside a Liar's Brain

A Look Inside a Liar's Brain
Valeria Sabater

Written and verified by the psychologist Valeria Sabater.

Last update: 05 September, 2023

One fundamental character of the human brain is plasticity. Therefore it’s not so strange to see lying as a skill like any other. If that’s the case, it means all you have to do is practice every day to keep your skills at peak level.

For example, some people are passionate about math, design, writing, etc, and their brains are shaped by it.

Psychology and sociology have always taken an interest in the world of lies and deceit. But for the past few decades, thanks to huge advances in diagnostic techniques, neuroscience is the field that’s given us the most valuable — yet worrying — information.

Why is it so worrying? If we told you right now that a dishonest personality comes from consistent training and habit-forming, it might take a lot of you by surprise.

You start off with small lies and then they turn into a habit. Then, your brain slowly starts to become desensitized to them. Little by little, bigger lies won’t cause you much pain to tell, and they will basically become a lifestyle…

A liar's brain.

A liar’s brain and the amygdala

You probably notice lying in celebrities or other well-known figures. For example, there are the politicians who cling to their lies. They defend their honesty and normalize acts that are sometimes even criminal. Are all these things just part of their jobs as public servants, or is there something biological at play?

Tali Sharot, professor of neuroscience at University College London, has something to say about this. She says that there is a biological component, but that there’s also a training process involved.

One part of the brain has a very clear, direct relationship to dishonest behaviors. That part is the amygdala. A liar’s brain actually goes through a highly sophisticated process of self-training, and this training is what helps it discard any feelings of guilt.

There’s a very interesting article about this from 2017 in Nature Neuroscience magazine. They go quite in depth. But it will probably help if we give you an example as well.

Picture for a second a young person who has reached a position of power in their company. They want to convey leadership and trust to their employees, so they start telling small lies.

These “dissonances,” these small deceits, activates the amygdala. This tiny structure in the limbic system deals with memory and emotional reactions. It’s also the part of the brain that conditions how willing a person is to lie.

A child's brain.

In the end, that young leader starts to turning to lies constantly. Now their job is entirely based on permanently and purposefully deceiving people.

When this kind of behavior becomes a habit, the amygdala stops reacting. It builds up a tolerance and stops sending out any type of emotional reaction. Feelings of guilt go away, and you’re left without any regret or worry.

To put it one way, a liar’s brain has adapted to dishonesty.

Lies make the brain work differently

People who lie need two basic things: memory and emotional coldness. This is exactly what Duke University psychology professor Dan Ariely says in his book The Honest Truth About Dishonesty: How We Lie to Everyone–Especially Ourselves, one of the most in-depth looks at a liar’s brain. He also talks about many other related neurological processes related that are just as fascinating.

Dr. Ariely himself did an experiment on the subject. The results showed that the brains of pathological liars had 14% less grey matter. But they also had between 22 and 26% more white matter in their prefrontal cortex.

What does that mean? Basically, a liar’s brain makes a lot more connections between their memories and their ideas. A bigger web of connections means they can access these associations more quickly and make their lies consistent.

man with mask symbolizing a liar whose brain works differently

It’s big clue about how dishonesty starts from the inside. It starts with cognitive processes that get stronger the more you practice them. At the same time, your brain will also start to involve fewer emotions in your actions.

Dr. Ariely finds it frightening. The fact that our amygdala can stop reacting to certain things means that we can also start to lose something that makes us human.

When you can’t see the consequences that your actions have on other people, you lose the natural goodness that should exist in every single human being.

A liar’s brain takes shape through certain rather dark motivations. Inside a person who has made lying a lifestyle are certain very specific goals: a desire for power, status, domination, and self-interest.

It’s the ideology of people who at some point or another decide to put themselves above everyone else. There’s nothing more disturbing than that.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.