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You’ve probably heard of that classic philosophical conundrum known as the trolley problem: A trolley is speeding toward a group of five people stuck on the track. You happen to be next to a lever that could change the trolley’s direction, sending it onto a track where one person is standing; that one person would die, but five would be saved. Would you do it? What about if that one person isn’t actually standing on the track, but actively pushing them in front of the trolley will save the other five?

Your answer, as it turns out, may depend on the language in which you hear the question: In Scientific American this week, linguist and psychologist Julie Sedivy highlighted recent research illustrating how language can shape a person’s sense of morality.

For example, in one study published last year in the journal PLOS ONE, researchers presented native English and Spanish speakers with the trolley problem. Most of the study participants said they would flip the lever, but that number dropped when the researchers presented them with the twist: When the participants heard the question in their native language, less than a fifth said they’d be willing to push the lone person into harm’s way. But when they heard it in the language that wasn’t their first — Spanish for the native English speakers, and vice versa — around half said they’d be willing to do it.

And in a second study, published last year in the Journal of Experimental Psychology, researchers asked people to judge actions that were morally questionable, but not directly harmful — for example, a man cooking and eating a dog that’s already died. Again, people were more morally stringent when they read the stories in their native language, rendering harsher verdicts than those who read them in a foreign one.

Why does language make a difference? Sedivy offers a few possibilities:

According to one explanation, such judgments involve two separate and competing modes of thinking—one of these, a quick, gut-level “feeling,” and the other, careful deliberation about the greatest good for the greatest number. When we use a foreign language, we unconsciously sink into the more deliberate mode simply because the effort of operating in our non-native language cues our cognitive system to prepare for strenuous activity.



An alternative explanation is that differences arise between native and foreign tongues because our childhood languages vibrate with greater emotional intensity than do those learned in more academic settings. As a result, moral judgments made in a foreign language are less laden with the emotional reactions that surface when we use a language learned in childhood.



Both hypotheses boil down to the same basic idea: That we may learn to speak and even think in another language, but our baser instincts — judgment, intuition, emotion — don’t translate so easily. In the language that comes most naturally to us, those things will butt up against, and often overpower, cold rationality; in one that’s less familiar, rationality stands more of a fighting chance.