Every Time You Tell a Lie, You Feel Less Guilty About Lying

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What makes a good liar? First and foremost, someone who does it a lot — like any other skill, lying becomes easier with practice.

It also becomes a bit of a vicious cycle: The more you do it, the better you become; the better you become, the more you do it. And as Jessica Hamzelou reported this week in New Scientist, researchers may have figured out why lies so often seem to spawn more lies: A study recently published in the journal Nature Neuroscience found that each individual lie desensitizes the brain just a little bit more to the guilt-inducing effects of dishonesty.

To test their subjects’ lying abilities, the study authors set up a game that gave them incentive to be dishonest, measuring their brain activity as they played. Hamzelou explained:

In the task, each person was shown jars of pennies, full to varying degrees. While in a brain scanner, each person had to send their estimate to a partner in another room.

The partner was only shown a blurry low-resolution image of the jar, and so relied on the volunteer’s estimate. In some rounds, a correct answer would mean a financial reward for both the volunteer and their partner. But in others, the volunteer was told that a wrong answer from the partner would result in a higher reward for them, but a lower reward for their partner – and the more incorrect the answer, the greater the personal reward. In other rounds, incorrect answers benefited the partner, but not the volunteer.

The participants lied for reasons both altruistic and selfish, with one key difference: When they fibbed to get their partner more money, the size of the untruth tended to remain constant from round to round. But when their own rewards were on the line, the volunteers told bigger and bigger whoppers as they game went on. (“For example, a person might start with a lie that earned them £1, but end up telling untruths worth £8,” Hamzelou wrote.)

The selfish lies in particular, the researchers discovered, corresponded to an uptick of activity in the amygdala, the area of the brain that deals with emotion — but with each subsequent statement, that pattern became less and less pronounced, indicating that the emotional cost of lying was decreasing over time. Sophie van der Zee, a psychologist at the Free University in the Netherlands who wasn’t affiliated with the study, explained the phenomenon this way to New Scientist: “When you lie or cheat for your own benefit, it makes you feel bad,” which isn’t necessarily the case with lies told to help out someone else. “But when you keep doing it, that feeling goes away, so you’re more likely to do it again.” For better or worse, practice makes perfect.