Liars And Honest People Have Entirely Different Brains

By Debra Kelly on Saturday, January 3, 2015
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“Half the world knows not how the other half lies.” —George Herbert

In A Nutshell

Studies on the brains of people who have a history of lying have shown that they’re wired a little differently than the brains of people who are, for the most part, honest. The brains of habitual liars show an average of 25 percent more white matter and 14 percent less gray matter than the brains of their honest counterparts. The implication is that the brains of liars are wired to be more in tune with the story-telling and the reading of other people, while at the same time having fewer connections that govern moral choices.

The Whole Bushel

Everyone lies at some point; it’s part of human nature. Much of the time, we do it to spare someone’s feelings. We say things like, “No, it’s all right, I love hanging out with your friends, they’re great!” or something like, “Oh, your baby’s adorable, and so smart!” Our intentions are generally good in these cases, and without the ability to lie, navigating the social waters of the world would be much, much more difficult.

But we know when we’re doing it, and we can control it. For pathological liars, they’ve been found to do it for no good reason whatsoever, without even realizing that they’re doing it.

And their brains are wired differently than the rest of us.

A team of researchers from the University of Southern California took a look at a sample of random people. After a series of personality tests, they found 12 people were classified as habitual liars, 16 that could be described as having antisocial personalities without being regular liars, and 21 who tested as normal. Once they had their group, they performed MRIs on all the subjects in order to determine if there was a difference in the way their brains were wired.

The brains of the pathological liars had more than 25 percent more white matter in their pre-frontal lobes when compared to the anti-social group. Compared to the normal, control group, they had about 22 percent more white matter.

Gray matter was a different story, though, and the pathological liars had about 14 percent less gray matter than the normal group.

The implications are twofold. The increased white matter gives regular liars the ability to come up with stories very, very quickly—so quickly that it’s hard to tell whether they’re lying or telling the truth. It also gives them added processing power to gauge the responses and reactions of the people they’re talking to, to see if it’s working and make adjustments as necessary.

The idea of reduced gray matter is also pretty significant, as it’s the gray matter of the pre-frontal lobes that helps govern what choices we make. It’s our moral center, and with reduced gray matter the researchers suggest that not only are pathological liars’ brains equipped to come up with the tall tales and the stories, but they’re also equipped not to see anything morally wrong about their constant lying.

What’s not clear is what comes first. They don’t know if lying somehow trains the brains and increases growth in some areas while decreasing it in others, or if certain people are just born with brains that encourage lying.

Researchers took the idea another step with the brains of people who had been diagnosed with autism. Previous studies have shown that people with autism have difficulty in fabrication and telling lies, and part of the difference in their brains is the slow growth of white matter.

There are also a number of other factors that account for the presence of pathological lying as part of a person’s personality, and that can include diverse environmental factors.

Show Me The Proof

NPR: Into the Brain of a Liar
USC: Liars’ Brains Wired Differently
BBC News: Liars’ brains ‘are not the same’