A runaway trolley is about to kill five railroad workers. The only way to stop it is to shove a huge man next to you onto the tracks. Would you kill that man to save five?
That is one of the standard moral dilemmas  that scientists are using to study how people decide between right and wrong. But is it the best example? When was the last time you faced a runaway trolley?
To see how people deal with more realistic choices, Joshua Greene, a psychologist at Harvard University, and his undergraduate student Katie Ransohoff, turned to medicine and public health. They recruited 84 medical doctors and 69 public health professionals—people who manage health resources such as Medicare or plan vaccination campaigns but don't treat patients—and posed the sort of moral dilemmas that can crop up in their professions. For example: To save the lives of several patients who need brief access to life support, you need to pull the plug on a more gravely ill patient and redistribute the limited supply of machines in a hospital. In another example, you must decide between saving a few lives now with very expensive treatments or preventing many more deaths with thousands of cheap diagnostic tests. The researchers also posed the standard series of dilemmas involving the runaway trolley. As a control, they also quizzed 110 people from unrelated professions.
The doctors' decisions in both the trolley and the medical dilemmas were not statistically different from the control group, Greene reported last weekend at the annual meeting  of the Association for Psychological Science in Washington, D.C. Only 12% of doctors were willing to kill a man to save the five railroad workers, for example. But there was a wide gap between doctors and their administrators: 21% of the public health professionals said that killing the man was the morally correct action to take. The same trend held for medical decisions. Nearly half of public health professionals were willing to pull the plug on a patient's life support to save others, compared with less than a third of doctors.
The results make sense in light of doctors' oath to "do no harm," Greene says. He points out that some problems, such as the overprescription of antibiotics that leads to widespread resistance among bacteria, do require doctors to sacrifice the interests of their patients for the greater good—and yet doctors continue to overprescribe. The trolley dilemmas may seem artificial, Greene says, but they represent extreme versions of moral decisions "we make in our everyday lives."
The next step would be a study that tracks public health professionals before and after their training, says Daniel Wikler, a bioethicist at Harvard School of Public Health in Boston, who helped Ransohoff design the medical dilemmas. Does an education in public health make people more willing to sacrifice an individual for the greater good, he wonders, or do such people gravitate to this field in the first place? People clearly differ in their moral reasoning, but whether those differences are due to nature or nurture remains to be seen.