Small lies can lead to 'slippery slope' of falsehoods

Deceit is a practiced trait, according to a study released Monday that said small lies desensitize the brain to negative emotions, possibly leading to bigger lies in the future.

The research is the first of its kind in providing empirical evidence that our brains adapt to escalating lies over time.

Scientists scanned the brains of volunteers who took part in a task where lying could result in personal gain. When a person lied for the first time, it heavily activated the brain region known as the amygdala -- associated with emotion. The amygdala's response declined, however, with each subsequent lie, even if the lie's magnitude significantly increased.

Scientists were especially surprised to find that larger decreases in amygdala activity could accurately predict that someone would tell bigger lies in the future.

Researchers from Duke University and University College London (UCL) published the study in the journal Nature Neuroscience.

"When we lie for personal gain, our amygdala produces a negative feeling that limits the extent to which we are prepared to lie," UCL's Tali Sharot, the study's senior author, said 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."

Because the amygdala is linked to all sorts of emotional behavior, researchers believe the findings could lead to additional studies that could unlock much more about treacherous human actions.

"This is in line with suggestions that our amygdala signals aversion to acts that we consider wrong or immoral," said researcher Neil Garrett of the UCL. "We only tested dishonesty in this experiment, but the same principle may also apply to escalations in other actions such as risk taking or violent behavior."