Aug 25, 2010
The ability to evaluate other people’s actions as right or wrong can be disrupted with an electromagnetic pulse to the brain, according to a study conducted by researchers from the Massachusetts Institute of Technology and published in the Proceedings of the National Academy of Sciences.
“You think of morality as being a really high-level behavior,” lead researcher Dr Liane Young said. “To be able to apply a magnetic field to a specific brain region and change people’s moral judgments is really astonishing.”
Researchers had 20 volunteers listen to several scenarios, then assess the ethics of the people involved. In one experiment, some of the participants received a 25-minute burst of transcranial magnetic stimulation (TMS) to the nerve cluster known as the right temporo-parietal junction (RTPJ) before hearing the stories. In another experiment, some participants received the TMS burst for only 500 milliseconds after the stories, while being asked to make a judgment.
A TMS burst induces currents in the brain , causing nerve cells to malfunction.
The researchers found that in both cases, a TMS burst to the RTPJ made participants incapable of differentiating between morality and outcome. For example, participants were asked if a man acted ethically in allowing his girlfriend to cross a bridge he knew to be unsafe. When told that she made it safely across, participants whose RTPJ had been interfered with said the man had acted ethically, if she did not make it across, they said he had acted unethically.
- A d v e r t i s e m e n t
Previous studies have found that the RTPJ becomes especially active when people think about others’ behavior or thoughts. The new research  suggests it plays an important role in moral judgments that involve understanding other people’s intentions.
“What is interesting is that this is a region that is very late developing – into adolescence and beyond right into the 20s,” said Sarah-Jayne Blakemore of University College London “The next step would be to look at how or whether moral development changes through childhood into adulthood.”
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