People with great willpower are often lauded over their peers with less self-control. But having strong character may not always be a good thing.

Few years ago, 80 Parisians were given the chance to take part in the pilot of a new game show, called La Zone Xtrême. The producer greeted each participant at the studio and told them that they would appear in pairs – one as a “questioner”, and one as the “contestant”.

It was only once the participants arrived on stage, and the host explained the rules, that things got decidedly dark. The questioner was told to punish the contestant for any wrong answers with a sharp electric shock.

They would have to increase the intensity each time, up to a total of 460 volts – more than twice the voltage of a European power outlet. If the pair made it through 27 rounds, they would win the show.

The contestant was then taken into a chamber and strapped into a chair, while the questioner sat centre stage, and the game commenced.

Since it was simply a pilot show, the participants were told there was no monetary prize for winning the game – yet the vast majority of the questioners continued to administer the shocks, even after they could hear the screams of pain emanating from the chamber.

Thankfully, these cries for help were just an act – there was no electric shock. The questioners were unknowingly participating in elaborate experiment that allowed scientists to explore the way various personality traits could influence moral behaviour.

You might expect the worst offenders to have been impulsive and antisocial – or, at the very least, with no strength of character.

Yet the French scientists found the exact opposite. It was the participants who scored highest on conscientiousness – a trait normally associated with careful, disciplined and moral behaviour – who were willing to administer the greatest shocks.

“The people who are accustomed to being agreeable and organised, and whose social integration is good, find it more difficult to disobey,” explains Laurent Bègue, a behavioural scientist at the University of Grenoble-Alpes who analysed the participants’ behaviour.

And in this case, that personality profile meant they were willing to torture another human being.

These findings join a spate of new studies showing that people with high self-control and discipline have a surprising dark side.

This research can help us understand why model citizens sometimes turn toxic, with important implications for our understanding of unethical behaviour in the workplace and beyond.

Overcoming impulses

For decades, self-control had been seen as an unalloyed advantage. It can be assessed in various ways – from the questionnaires studying conscientiousness (which considers someone’s preference for self-discipline and organisation) to experimental measures of willpower (such as the famous “Marshmallow Test”).