磁脉冲能让你的道德观改变?

如果在你的右耳附近脑区放置一个磁脉冲的话，你的道德观将会立马发生转变。这是否有可能呢？来听听美国国家科学院院刊的研究报告怎么说.

Brain scientists have discovered something remarkable about the moral judgments that we make. They can be changed almost instantly by delivering a magnetic pulse to an area of the brain close to the right ear.

NPR's Jon Hamilton reports on the surprising link between magnets and morality.

JON HAMILTON: To study how people make moral judgments, you tell them a carefully constructed story and see how they respond. Liane Young, a researcher at MIT, has been using stories that start out like this.

Mr. LIANE YOUNG (Researcher, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology): Two people are taking a tour of a chemical factory, and the protagonistnamed Grace decides to pour her friend some coffee. She puts some powder in her friend's coffee...

HAMILTON: And at this point, the story can go in several directions. In one, Grace believes the powder is just sugar, but it's actually poison, and her friend dies. Young says in another version...

Ms. YOUNG: Grace tries to poison her friend. She thinks that she's putting poison in her friend's coffee but lo and behold, it turns out to be sugar, and so she fails to poison her friend.

HAMILTON: People who hear these stories generally forgive Grace for unwittingly poisoning her friend, but they condemn her for the failed attempt to do harm. Young says that's pretty typical of how we make moral judgments.

Ms. YOUNG: We judge people not just for what they do but what they're thinking at the time of their action, what they're intending. And this happens spontaneouslyand automatically. It happens when we're figuring out who to be friends with, who to punish and reward. We want to be with people who wish us well.

HAMILTON: But what if something, say a magnetic pulse, made it hard for us to understand another person's intentions? Would that affect our moral judgments?

To find out, Young and her colleagues manipulated a part of the brain called the right temporoparietal junction. It's near the surface of the brain, above and behind the right ear, and it seems to help us decipher another person's beliefs.

Young's team used a technique called transcranial magnetic stimulation, or TMS, to briefly interrupt activity in this part of the brain while 20 volunteers responded to stories like the one about Grace and the coffee. And Young says the magnetic pulses made a significant difference.

Ms. YOUNG: If no harm was done, then subjects when we applied TMS to this area would judge that as okay, as more or less permissible.

HAMILTON: Even if the story made it clear Grace was trying to do harm, people's brains were ignoring the intention and focusing on the outcome. Young says that's the sort of moral judgment you often see in kids.

Ms. YOUNG: Ask a young child who's around three or four years old whether a boy who breaks five teacups accidentally is more naughty than one who breaks one teacup intentionally. They'll say the one who broke more teacups is more naughty and more bad.

HAMILTON: Presumably, because their brains are still developing the ability to understand the intentions of other people.

Joshua Greene of Harvard University says the fact that scientists can adjust morality with a magnet may be disconcerting, if you think morality is a lofty and immutable human trait.

Mr. JOSHUA GREENE (Psychologist, Harvard University): Moral judgment is just a brain process, and that's precisely why it's possible for these researchers to influence it by using electromagnetic pulses on the surface of the brain.

HAMILTON: Greene says this study is part of a much larger effort by scientists to explain how the brain creates moral judgments.

Mr. GREENE: What we're essentiallytrying to do collectively, all of us in this field, is take this mysterious thing that we often associate with the soul or the mind as independent of the brain and actually break it down in mechanical terms.

HAMILTON: Greene says if something as complex as morality has a mechanical explanation, it will be hard to argue that people have, or need, a soul. The new research appears in the Proceedings of the National Academy of Sciences.

Jon Hamilton, NPR News.