Adapting Dishonesty: Here's What Happens in Your Brain When You Lie

A new study revealed that consistent small lies could alter the way on how a certain part of the brain associated to negative emotions respond to lie, desensitizing our brain in the process and encourages bigger lies in the future.

The study, published in the journal Nature Neuroscience, is the first to provide empirical evidence that telling small lies could gradually lead to larger lies. Additionally, the study is also the first to have a deeper look on the brain's responses to repeated and increasing acts of dishonesty.

"When we lie for personal gain, our amygdala produces a negative feeling that limits the extent to which we are prepared to lie," explained senior author Dr Tali Sharot, from University College London Experimental Psychology, in a statement. "However, this response fades as we continue to lie, and the more it falls the bigger our lies become. This may lead to a 'slippery slope' where small acts of dishonesty escalate into more significant lies."

For the study, the researchers recruited 80 volunteers. The participants took part in a team estimation task that involved guessing the number of pennies in the jar and sending their estimates to unseen partners using computers. The researchers introduced the participants in different scenarios that may affect their estimation. As the baseline scenario, the participants were told that aiming for the most accurate estimate would benefit them and their partners. Other scenarios include over- or under-estimating the amount of pennies would either benefit them both, benefit them at their partner's expense, benefit their partners at their expense and benefit one of them without any effect on the other one.

The researchers observed that participants started exaggerating their estimates in the scenario in which over-estimating would benefit them at the expense of their partner. The exaggeration of the estimates elicited a strong response from the amygdala. However, as the Due exaggerations of the estimate continue to escalate throughout the study, the response from the amygdala declined.

These findings show that the amygdala signals aversion to acts that considered to wrong or immoral. However, repeated acts of dishonesty can solicit a blunt response from the brain, reducing the emotional response to dishonest acts.