A new study suggests psychopaths are good for society, because they're quick to make decisions for the greater good.

A University of Plymouth study has used virtual reality to put people in a situation where they can push another person off an overbridge to stop a train crashing into five other people.

Study co-author, Dr Sylvia Terbeck told Mike Hosking people with lower empathy levels and high selfishness, were much quicker to act.

"They were just doing this action which many people did in the virtual world anyway but with just some strong power behind that."

LISTEN ABOVE AS SYLVIA TERBECK SPEAKS WITH MIKE HOSKING