Is a fatal push fair to save others?
Editorial: 鈥�If morality is broken, we can fix it鈥�
WHY do we sometimes wrestle with moral dilemmas? A twist on a classic psychology experiment suggests that our minds have two parallel moral systems, and they don鈥檛 always agree.
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In the trolley experiment, participants are told that a runaway tram trolley could kill five people on the tracks. They must decide whether to divert it onto a second track with only one person on it. diverts it, sacrificing one to save five.
But if instead you have to push one person off a bridge onto the track to stop the trolley, most people demur. That suggests most of us have a strict rule against killing people directly, even for the greater good.
How are such rules formed? Although moral codes appear to rule out the act of killing in the bridge experiment, most moral behaviour in animals appears focused on outcomes 鈥� the death of an individual, say 鈥� rather than the act that brought it about. When an animal experiences harm to help a relative, evolutionary biologists view this as increasing the chances that copies of the animal鈥檚 genes will survive. Many psychologists think that human moral rules are an extension of this 鈥渒in selection鈥�.
Robert Kurzban of the University of Pennsylvania in Philadelphia thinks there鈥檚 more to it than that. His latest study suggests there are moral rules that arose independently of those shaped by kin selection.
Kurzban鈥檚 team gave volunteers variations of the bridge scenario. Volunteers were asked what they would do and whether their actions were morally right. Eighty-five per cent of them said it would be morally wrong to push one person off to save five, whether these people are brothers or strangers, confirming the idea that there is a rule against killing.
However, despite thinking it wrong, 28 per cent said they would still push a stranger off to save five, while 47 per cent said they would push a brother off to save five brothers. 鈥淭hey鈥檙e more likely to do this 鈥榣ess moral鈥� thing if it鈥檚 to save a relative,鈥� Kurzban says, suggesting kin selection is at work as well as the basic 鈥渕oral rule鈥� against killing ().
The experiment shows we have at least two parallel systems for deciding right and wrong: one that says some actions, like killing, are bad, and another that tells us to protect kin. They can clash, so how is this helpful? Co-author of Brandeis University in Waltham, Massachusetts, says social cohesion demands we have rules, regardless of what they are, to help resolve disputes quickly and peacefully.
鈥淪ocial cohesion demands we have rules, regardless of what they are. Rules let disputes be resolved鈥�
DeScioli says our rule-making system is arbitrary, producing the belief that masturbation is 鈥渂ad鈥�, for instance. The good news is that such rules can be changed.
But some may be harder to change than others, says Fiery Cushman of Brown University in Providence, Rhode Island. He says our protectiveness towards relatives influences rule-making, otherwise there would not be universal injunctions against theft, rape and murder.
