The Frontal Cortex

The Lying Brain

Radio Lab delves into the mystery:

Yang and her colleagues put all 49 people, both the liars and the non-liars, into a magnetic resonant imaging scanner and took pictures of their prefrontal cortex. They chose to focus on this area of the brain because previous studies had shown that the prefrontal cortex plays a role in both lying and in antisocial behaviors.

If you could look into this part of the brain, which sits right behind your forehead, you would see two kinds of matter: gray and white. Gray matter is the groups of brain cells that process information. Most neuroscience studies focus on gray matter. But nearly half the brain is composed of connective tissues that carry electrical signals from one group of neurons to another. This is white matter. Roughly, gray matter is where the processing happens, and white matter connects different parts of the brain, helping us to bring different ideas together.

The liars in Yang’s study had on average 22 percent to 26 percent more white matter in their prefrontal cortex than both the normal and antisocial controls. Yang speculates that the increase in white matter means that people who lie repeatedly and compulsively are better at making connections between thoughts that aren’t connected in reality — like, say, “me” and “fighter pilot.”

Interesting stuff. As a culture, we draw this big distinction between lies we tell to other people and lies we tell to ourselves (aka self-delusions). The brain, however, is the ultimate category buster. I wonder if it also distinguishes between these different kinds of dishonesty. For instance, the prefrontal cortex is also responsible whenever the brain deceives itself. People who benefit from the placebo effect, or think expensive wine tastes better than cheap wine (even when it’s actually the same wine), or are convinced that discounted energy drinks are less effective, are also liars: the only difference is that their prefrontal cortex is deluding the rest of the brain, and not some other brain.

I’d like to see a study that compared self-deception and the deception of others. Would there be a big difference? I’d expect there to be some extra cingulate activity when we lie to others, since the cingulate seems to be responsible for monitoring our social reputation. But the source of the lie itself – the promethean prefrontal cortex – just might stay the same.


  1. #1 j-Dog
    March 6, 2008



  2. #2 Rachael
    March 6, 2008

    That’s pretty cool… how about the connection between lying / compulsivity / creativity? If concepts are more readily connected in these peoples minds, I wonder if there are cognitive effects

  3. #3 Elizabeth
    March 7, 2008

    Quickly, I grew up in a town called MT. Carmel located on the floor of a valley from which I could see the town of MID-VALLEY situated on the mountain side. The towns were mis-named during the Civil War period.

    As a youngster, several such encounters led me to understand the world does not always make sense.

    Hence, I came to appreciate the value of factual information; truthfulness was, and remains important to me.

    When the demands of higher learning challenged my mental capacity, I held fast to ‘truth telling / not lying’ as the most EFFICIENT use of the brain… ie, it is sometimes hard enough to remember what ‘really may have happened’ without having to remember who I told what to and when. A clear mind not only allows one to sleep well at night, but also keeps one open to the random “machinations” of creative thought.

    I once explained that developing a friendship is not unlike learning about any phenomenon… the data need to be true in order to know the person; hence, truthfulness in relationships is also important.

    In addition to the other / self deception mentioned, the big lie versus little lie must add further confusion to those connections when the little lie becomes responsible for some big consequences.

  4. #4 Kerry D. Friesen, M.D.
    March 8, 2008

    Buddha said it best. We are in fact all self deluded. For most people a single moment of clarity in an otherwise inane life would serve to confirm that. What’s truly surprising is how content we are with self-delusion. Despite how diligently we seek the “seat of consciousness” with neuroimaging and nanotechnology, seemingly “self” seeks to delude itself even more. Who knows, fMRI may one day find Descartes proverbial “ghost in the machine”.

  5. #5 michael
    March 13, 2008

    this still doesnt show us why people lie. very off topic

  6. #6 magdy abdalshafy
    July 12, 2009

    Hi all my friends
    The Holy Quran, God’s last word to humanity and the book revealed to Prophet Mohammed of Islam, states that the frontal lope is the part which is reponsible for taking descision especially wicked descion…This is not the only scientific statement in Quran, there are also statement on fetus development, universe, galaxies, pulsar, supernova, black hole, end of the sun as a red giant , geology , ocean sciences …

  7. #7 cesc fabregas
    November 6, 2011

    it is right
    i study quran .it is right entirely
    quran and science is mached

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