Study assesses the 'good' side of being a psychopath

Participants were asked to virtually push a victim into the path of an oncoming train to stop it hitting several workmen further down the track. Photo / AP

Psychopaths can be beneficial for society because in morally dubious situations they make pragmatic choices for the greater good, a study suggests.

Although psychopaths are often viewed as dangerous, cold or lacking empathy, in fact, in certain situations, such traits can be helpful.

For example, it means they would not think twice about throwing a stranger under a bus to prevent it crashing into five people down the road.

A study led by the University of Plymouth compared people's judgments in moral dilemmas with how they scored in measures of psychopathy.

Participants had to decide whether to sacrifice a person by performing a harmful action against them in order to save a larger group of people.

In one moral quandary they were asked to push a victim off a footbridge into the path of an oncoming train to stop it hitting several workmen further down the track.

Participants were invited to give their response by squeezing on a robotic handle, which measured the strength of their action. A weaker squeeze suggested they would not carry out the morally dubious action.

The research showed that people with strong psychopathic traits were more likely to generate harmful actions with greater physical power, meaning there is was a greater chance they would go through with it.

Dr Kathryn Francis, who carried out the study while at Plymouth's School of Psychology, said: "For the first time, we demonstrate how personality traits can influence the physical power of our moral actions."

The research was published in the journal Scientific Reports.