Study Suggests Small Fibs Snowball Into Larger Lies As Brain Adapts To Dishonesty


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Chronic or compulsive lying has largely been considered a mental illness. However, a new study from the University College London suggests that there may be a biological explanation as well. The researchers believe that small, self-serving lies desensitize our brains to the negative emotions connected to dishonesty, paving the way for bigger lies.

Participants were presented with pictures of glass jars containing
different amounts of one-penny coins and entered their advice
regarding how much money is in the jar. (Image Nature.con)

The team, led by Tali Sharot, director of the University’s Affective Brain Lab, began by presenting 80 volunteers, ages 18 to 65, with several images of glass jars filled with pennies.

The participants were told that they would have a full three seconds to gauge the amount of money in each and send the information to an unseen partner. Since their counterpart only had access to blurry images for just one second, they would primarily be relying on the advice they received from the volunteer “estimators.”

The volunteers were then given several different scenarios, each designed to provide them with an incentive, to be honest or dishonest. The first base case test benefited both parties equally, thus giving the estimators no reason to exaggerate the amount of cash in the jars. In the various other scenarios over-or-underestimating the amount helped both, the estimators at the expense of their partners or vice versa, or only one of the two with no impact on the other.

The researchers say that while the participants started by exaggerating the cash amount by a little, it escalated over time. Interestingly, the lies were not always for selfish gain. The volunteers were also willing to lie to benefit their partners. However, the magnitude of those lies did not grow as much over time.

Reduction in sensitivity to dishonesty over time (Image:

Additionally, when the lie helped the participants at the expense of their partner, they lied to the tune of £7 pounds ($9) but when it was beneficial to both, the amount went up by as much as £13 ($16.5) Sharot says “that’s likely because lying that also benefits someone else doesn’t feel as bad.”

To see if the escalating dishonesty is associated with the brain, 25 participants performed the tasks in a functional MRI scanner, allowing the researchers to measure their brain activity. The scientists, who published the results in the October issue of the journal Nature Neuroscience, say that the amygdala, a part of the brain that processes emotion, responded strongly when people lied for the first time. However, this response gradually declined with every lie, even as the magnitude of the lie kept increasing.

The scientists assert that the reduction in amygdala activity was a result of “emotional adaptation,” which causes neural responses to repeated stimuli to decline over time. "The first time you cheat on your taxes, for example, you might feel quite bad about it," Sharot said. "But the next time you cheat, you have already adapted, and there is less of a negative reaction to hold you back — and you might lie more."

The human brain (Photo Credit: By OpenStax CC by 3.0 via Wikimedia Commons

While neuroscientist Lisa Feldman Barrett finds the new research interesting, she is not entirely convinced. The professor of psychology at Northeastern University and author of the forthcoming book, "How Emotions are Made: The Secret Life of the Brain," believes that focusing on the amygdala as the brain's source of emotion may be misguided, given that it is not critical for emotion. She also wonders if we would see similar results outside the lab given that, “They (the researchers) did not reward or punish for lying, whereas there is always a payoff or risk in real life." The expert speculates the lack of fear of being caught, could be another reason why the amygdala stopped reacting after the first lies. However, she like the other scientists does agree on one thing – the more you lie, the easier it gets. So try not to go down that slippery slope!


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