Emotion key in making tough moral decisions

WASHINGTON -- Here's the dilemma: A runaway train will kill five people unless you flip a switch sending it onto another track where it will kill only one.

Most people say flipping the switch is moral.

But what if the only way to stop the train is to push a passer-by onto the track? You still save a net of four lives, but most people say that's not moral.

Why people have such different reactions to the same end has long puzzled philosophers. Now Princeton University researchers have scanned volunteers' brains while they pondered similar ethical dilemmas -- and found that a key to tough moral judgments is emotion, not logical or analytical reasoning.

The study doesn't say what's a right or wrong decision. But for the first time, images of which brain areas are activated -- they literally light up in the scans -- show how people make individual moral judgments.

'Groundbreaking' study

The research, published in Friday's edition of the journal Science, is groundbreaking, said Jonathan Haidt, a social and cultural psychologist at the University of Virginia.

"We don't really understand how our moral reasoning and judgment works," Haidt said. But he said the new study backs his own theory that "we carry out our lives as though our moral judgments are based on reason," but instead people act on "gut feelings and make up reasons post hoc."

The study illustrates "the rich way the two parts of us (emotional and analytical) seem to interact and come into play in just about every situation we encounter," said co-author Dr. Jonathan Cohen, director of Princeton's Center for the Study of Brain, Mind and Behavior.

And better understanding of how we make moral judgments could be important for society, said Joshua Greene, a Princeton philosophy graduate student who led the experiment.

"Most of the important social and political issues that divide people are really moral issues. And moral reasoning is highly structured by the structure of our brain. If we want to get along with one another and ... we see the world in varying moral colors, we need to understand where those pictures of the world come from," Greene said.

18 with brain scanners

Eighteen people were put into brain scanners while answering a battery of 60 questions:

The study doesn't say what's a right or wrong decision. Personal moral dilemmas like the runaway train case; whether, during a war, it's appropriate to smother a crying baby so invaders won't find and kill a whole group of people; a case of throwing people off a sinking lifeboat.

Impersonal moral dilemmas such as do you ignore appeals for money to save starving children even if you're well off, and do you keep the money if you find a lost wallet?

Non-moral questions such as how to navigate a complicated trip.

The people used emotion-related brain areas in deciding the personal moral questions far more than when they decided the impersonal or non-moral questions.

Also, areas of working memory -- for using cold logic -- were far less active while the volunteers debated the personal moral questions.

Then researchers tracked how long it took the volunteers to decide each question. The few who made such choices as pushing the passer-by onto the train track or people out of the lifeboat took far longer to make that decision.

"That suggests the emotions really are acting as interference for saying, 'yes, it's morally acceptable"' to sacrifice the few for the greater good, Cohen said.

The study is part of growing neurology research on the interaction between emotion and cognition.