Apparently a region of the brain just above and behind the right ear seems to control morality.
The scientists used magnetic pulses to block cell activity they impaired volunteers' notion of right and wrong.
The study was carried out by Massachusetts Institute of Technology, 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.
Sarah-Jayne Blakemore of University College London said:
The study suggests that this region - the RTPJ - is necessary for moral reasoning.
What is interesting is that this is a region that is very late developing - into adolescence and beyond right into the 20s.
The next step would be to look at how or whether moral development changes through childhood into adulthood.