In a study recently published in the journal PloS One, our two research teams, working independently, discovered that when people are presented with the trolley problem in a foreign language, they are more willing to sacrifice one person to save five than when they are presented with the dilemma in their native tongue.

One research team, working in Barcelona, recruited native Spanish speakers studying English (and vice versa) and randomly assigned them to read this dilemma in either English or Spanish. In their native tongue, only 18 percent said they would push the man, but in a foreign language, almost half (44 percent) would do so. The other research team, working in Chicago, found similar results with languages as diverse as Korean, Hebrew, Japanese, English and Spanish. For more than 1,000 participants, moral choice was influenced by whether the language was native or foreign. In practice, our moral code might be much more pliable than we think.

Extreme moral dilemmas are supposed to touch the very core of our moral being. So why the inconsistency? The answer, we believe, is reminiscent of Nelson Mandela’s advice about negotiation: “If you talk to a man in a language he understands, that goes to his head. If you talk to him in his language, that goes to his heart.” As psychology researchers such as Catherine Caldwell-Harris have shown, in general people react less strongly to emotional expressions in a foreign language.

-- Boaz Keysar and Albert Costa, Our Moral Tongue, New York Times, June 20, 2014