MIT neuroscientists have shown they can influence people’s moral judgments by disrupting a specific brain region — a finding that helps reveal how the brain constructs morality.
To make moral judgments about other people, we often need to infer their intentions — an ability known as “theory of mind.” For example, if a hunter shoots his friend while on a hunting trip, we need to know what the hunter was thinking: Was he secretly jealous, or did he mistake his friend for a duck?
Previous studies have shown that a brain region known as the right temporo-parietal junction (TPJ) is highly active when we think about other people’s intentions, thoughts and beliefs. In the new study, the researchers disrupted activity in the right TPJ by inducing a current in the brain using a magnetic field applied to the scalp. They found that the subjects’ ability to make moral judgments that require an understanding of other people’s intentions — for example, a failed murder attempt — was impaired.
The researchers, led by Rebecca Saxe, MIT assistant professor of brain and cognitive sciences, report their findings in the Proceedings of the National Academy of Sciences.
The study offers “striking evidence” that the right TPJ, located at the brain’s surface above and behind the right ear, is critical for making moral judgments, says Liane Young, lead author of the paper. It’s also startling, since under normal circumstances people are very confident and consistent in these kinds of moral judgments, says Young, a postdoctoral associate in MIT’s Department of Brain and Cognitive Sciences.
“You think of morality as being a really high-level behavior,” she says. “To be able to apply (a magnetic field) to a specific brain region and change people’s moral judgments is really astonishing.”
