Special to USA TODAY
Published 6:31 AM EDT Sep 11, 2019
I recently spent an evening at an event with the legendary comedian Jim Carrey. Carrey has starred in dozens of movies, but the one that always sticks with me is Liar Liar, where he played a man forced to always tell the truth. It was the perfect role, as Carrey’s antics were backstopped by the paradox of trying to determine whether or not it is a good thing to always be truthful. I loved every bit of the movie, but it also left me with a dull headache and a sense of mental exhaustion.
Ironically, the feeling is not much different than spending time with a liar. Whether a pathological liar in your family, a crazy person peddling conspiracy theories on the subway, or a friend of a friend who shares untrue posts on social media, the result is the same: a dull headache and a sense of mental exhaustion.
Separating truth from lies is mentally taxing, and the way our brains do it is different than you might expect. 27 years ago, Harvard psychologist Daniel Gilbert wrote an article in American Psychologist showing that we treat information the same way a court treats a suspect: innocent until proven guilty. This means that the brain starts by assuming information is true and then seeks to confirm or deny that truth.
Interestingly, we didn’t always know how the brain handled truth and lies. The seventeenth century French philosopher Rene Descartes assumed the process was more neutral. He guessed that after hearing a statement, you take a second to understand the meaning, and then either accept it as true or reject it as false. But then the Dutch philosopher Baruch Spinoza came along and suggested an alternate method, which Gilbert found evidence to support 200 years later.
It may seem like an insignificant difference, something for philosophers to argue over. But the implications are massive, especially in the era of #fakenews, aggressive marketing, and general untruthfulness.
If Descartes was right, we wouldn’t have a bias toward believing things and the world might not be such a trusting place. But what Gilbert demonstrated is that if the brain is overloaded, it will accept lies as truth. The reason is that when the brain becomes taxed, it essentially shuts down. So if we start by assuming something as true and the brain then becomes overloaded, there is little hope in changing course. As Gilbert explained explains it, “when resource-depleted persons are exposed to… propositions they would normally disbelieve, their ability to reject those propositions is markedly reduced.”
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Resource depletion could be as simple as having your attention divided between two tasks. Or it could come from stress, lack of sleep, or too much information. What’s more, there’s evidence to suggest that merely hearing too many lies can both overload the brain and reinforce a lie. Just as a suspect can be mentally overloaded into a confession, the brain can become overloaded with information and simply give up on trying to determine right from wrong. With time and stress, the truth becomes blurry.
Some lies aren’t entirely bad. White lies can protect people’s feelings; storytellers lie to accentuate a point they are making; businesses lie to sell products that sometimes offer real value; politicians lie to protect the public. But more often than not, lies are toxic. The trick is to distinguish between the lies meant to highlight the truth and those meant to hide the truth.
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We wear helmets to protect our brains from physical injury but no such device exists (yet) to prevent us from mental entanglements. Until then, the best we can do is to avoid shallow forms of information or anything that is likely to contain a lie.
Remaining vigilant is our best defense, but we are all bound to get tired or stressed. At that point, it may be best to avoid taking in any information at all. This may mean staying off Twitter or avoiding your mother-in-law. You can only refute so many lies before being overloaded. If you feel yourself getting there, do what I do and go hang out with your kids or take a walk on the beach with your dog. Even a stroll in the backyard with your cat will do: cats may not like you very much, but at least they’re honest.