NOV 03, 2016

What Happens in the Brain When You Tell a Lie

WRITTEN BY: Brenda Kelley Kim

There have been numerous studies showing that exposure to violence, in movies or video games, desensitizes humans to violence that happens in real life. Constant exposure to violent acts that happen on television or in games can change the brain’s reaction to violence, making it go a bit numb when confronted with violence in real life. As it turns out, the same may be true when we get used to telling lies. Similar to repeated violence, the brain becomes accustomed to common occurrences of deliberate deception and changes how it processes the tall tales. Eventually, it gets easier for people to lie. It’s a case of practice making perfect, but recent research on how the biology of the brain actually changes is something not shown before.

The new study is from researchers at University College London and suggests that once a person becomes used to telling lies that are “self-serving” or can lead to some sort of gain or advantage, there are detectable changes in the brain and these changes can predict the likelihood of the deceptive behavior continuing.

The study consisted of volunteers who agreed to undergo brain scans while they took part in tasks where they were allowed to lie for personal gain. The brain scans showed that when participants told their first lie, the amygdala, which is the brain region associated with emotion, showed increased activity. As the volunteers continued the task, and the lies grew in significance and complexity the activity first shown in the amygdala declined. The most surprising part of the research was that that as the lies grew, and the activity in the amygdala lessened, the team could use the data to accurately predict which participants would continue to lie in future tasks.

So what were the tasks and how did they involve deceit? 80 volunteers were placed on teams and asked to estimate how many pennies were in a jar. They then had to send these estimates to unseen partners via a computer. Different scenarios of this basic task were presented in which some of the time guessers were told that being as accurate as possible would benefit them and in other tasks they were told that over or under-estimating the amount would result in a personal gain. The gain in some situations came at the expense of their partners. At first, when participants would fudge the numbers there was a spike in amygdala activity but as they continued to falsify the amounts to their partners the activity declined.

Senior study author Dr Tali Sharot from the UCL Department of Experimental Psychology stated, "When we lie for personal gain, our amygdala produces a negative feeling that limits the extent to which we are prepared to lie. 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."

Sharot’s colleague, lead author Dr. Neil Garrett explained the possible connection to becoming desensitized to violence by explaining, "It is likely the brain's blunted response to repeated acts of dishonesty reflects a reduced emotional response to these acts. This is in line with suggestions that our amygdala signals aversion to acts that we consider wrong or immoral. 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."

The video below talks more about the study and what it could mean for research into deceptive and violent behavior.

Sources: University College London, Science News, Medical Daily