Transcranial magnetic stimulation (TMS). Photograph: Suzanne Kreiter/Getty Images
They identified a region of the brain just above and behind the right ear which appears to control morality.
And by using magnetic pulses to block cell activity they impaired volunteers’ notion of right and wrong.
The small Massachusetts Institute of Technology study appears in Proceedings of the National Academy of Sciences.
Lead researcher Dr Liane Young said: “You think of morality as being a really high-level behaviour.
“To be able to apply a magnetic field to a specific brain region and change people’s moral judgments is really astonishing.”
The key area of the brain is a knot of nerve cells known as the right temporo-parietal junction (RTPJ).
The researchers subjected 20 volunteers to a number of tests designed to assess their notions of right and wrong.
In one scenario participants were asked how acceptable it was for a man to let his girlfriend walk across a bridge he knew to be unsafe.
After receiving a 500 millisecond magnetic pulse to the scalp, the volunteers delivered verdicts based on outcome rather than moral principle.
If the girlfriend made it across the bridge safely, her boyfriend was not seen as having done anything wrong.
In effect, they were unable to make moral judgments that require an understanding of other people’s intentions.
Previous work has shown the RTPJ to be highly active when people think about the thoughts and beliefs of others. Text by BBC News. Continue HERE