How our brains adapt to dishonesty

New research shows how small lies escalate over time unveiling the biological basis for the slippery slope of dishonesty in our brains.

White lies are widely accepted as an integral part of our everyday lives. And yet history has taught us how a series of small transgressions can snowball with detrimental outcomes.

To find out whether and how we get desensitised to lying, Tali Sharot and her team at University College London involved 80 adults in a game, where they could repeatedly choose to lie for their own benefit.

The study, published in Nature Neuroscience this week, showed that the participants' level of dishonesty increased over time.

By measuring the brain activity with a fMRI (functional magnetic resonance imaging) scan, the scientists could then correlate escalating dishonesty with a decrease in the amygdala response, a brain region known to be involved in emotion processing.

"We could actually predict how much people are going to lie more on the next trial by looking at how much the amygdala response dipped. The more it dropped, the more likely participants were to lie in the future" says Sharot.

The brain's adaptation to dishonesty appears to be similar to adaptation to other stimuli, such as smell.

In the game, a participant was asked to advise their partner on the estimated amount of money contained in a glass jar.

The rules were altered so that the participant was incentivised to lie for the benefit of both, for self-benefit alone or for the benefit of the partner.

"People lied the most when it was beneficial to lie for your own benefit and someone else. [...] And they did not lie at all when it helped someone else but would hurt themselves."

On a positive note, the participant's lies never got as big as they could have.

It remains to be determined how long-lasting the adaptation effect is and whether it holds true in a real-world scenario.

But if it does, Sharot suggests a way to escape the slippery slope of dishonesty.

"We might want to nudge people away from small lies and [our study] also suggests a way to do so. Because if what carves our dishonesty is emotion, and in the absence of emotion we are more likely to lie, then you might want to try and arouse emotion in people."

So when we lie the next time, and we all will, let's feel at least really bad about it!