moral dilemma
Reactions to moral dilemmas can make a person appear trustworthy... or not Istock

Would you kill one person to save five? People who answer negatively to this question may be seen as more trustworthy, a study suggests. Scientists from the University of Oxford points out a lot of people make snap decisions based on a set of absolute moral rules (such as "don't kill innocent people") rather than on a costs/benefits analysis, and this makes them more popular with their peers.

Lead author Jim Everett said: "We compared two schools of thought about morality. Consequentialist approaches say we should aim to maximize the greatest good for the greatest number, even if this means causing some harm – like killing one person to save five."

"In contrast, approaches focus on moral rules and ideas of rights and duties, such that certain things – like killing an innocent person – are wrong even if they maximize good outcomes. People usually default to the deontological style of morality, suggesting these moral rules have in some way been coded into human nature. But why?"

The research, published in the Journal of Experimental Psychology, aimed to answer this by looking at how moral absolutes are associated with trust and social value.

Moral dilemma stories

The scientists recruited 2400 participants, and told them stories about difficult moral dilemmas. It involved choosing between killing an innocent person in order to save more people, or refusing to take his life, with the consequence of harming all the others.

One story described an out of control tram speeding towards a group of people. There was only one way to save them: pushing an innocent person on the tracks to stop the tram's course. He will die, but all the others will live. Participants were asked what they would do.

Scientists discovered that those who refused to kill the innocent, despite the fact it would save others, were viewed as better social partners. "People who took an absolute approach to the dilemmas were seen as more trustworthy", Everett explains.

There was however an exception to that rule. When in the story, participants were told that the person who might be sacrificed had a specific desire to live or a to die, people favoured individuals who respected those wishes, even if that involved killing.

Respecting others' wishes

The scientists conclude that responding to a moral dilemma has nothing to do with rationality, and is more a question of popularity. They believe people prefer to stick to moral absolutes because they correspond to rules valued by society, and it will make them appear more trustworthy.

"Rather than reflecting erroneous emotional thinking, making moral judgements based on rules may be an adaptive feature of our minds", Everett says.