Hypotheticals versus the real world: The trolley problem


Jason Collins


July 4, 2018

Daniel Engber writes:

Picture the following situation: You are taking a freshman-level philosophy class in college, and your professor has just asked you to imagine a runaway trolley barreling down a track toward a group of five people. The only way to save them from being killed, the professor says, is to hit a switch that will turn the trolley onto an alternate set of tracks where it will kill one person instead of five. Now you must decide: Would the mulling over of this dilemma enlighten you in any way?

I ask because the trolley-problem thought experiment described above—and its standard culminating question, Would it be morally permissible for you to hit the switch?—has in recent years become a mainstay of research in a subfield of psychology. …

For all this method’s enduring popularity, few have bothered to examine how it might relate to real-life moral judgments. Would your answers to a set of trolley hypotheticals correspond with what you’d do if, say, a deadly train were really coming down the tracks, and you really did have the means to change its course? In November 2016, though, Dries Bostyn, a graduate student in social psychology at the University of Ghent, ran what may have been the first-ever real-life version of a trolley-problem study in the lab. In place of railroad tracks and human victims, he used an electroschock machine and a colony of mice—and the question was no longer hypothetical: Would students press a button to zap a living, breathing mouse, so as to spare five other living, breathing mice from feeling pain?

“I think almost everyone within this field has considered running this experiment in real life, but for some reason no one ever got around to it,” Bostyn says. He published his own results last month: People’s thoughts about imaginary trolleys and other sacrificial hypotheticals did not predict their actions with the mice, he found.

On what this finding means for the trolley problem:

If people’s answers to a trolley-type dilemma don’t match up exactly with their behaviors in a real-life (or realistic) version of the same, does that mean trolleyology itself has been derailed? The answer to that question depends on how you understood the purpose of those hypotheticals to begin with. Sure, they might not predict real-world actions. But perhaps they’re still useful for understanding real-world reactions. After all, the laboratory game mirrors a common experience: one in which we hear or read about a thing that someone did—a policy that she enacted, perhaps, or a crime that she committed—and then decide whether her behavior was ethical. If trolley problems can illuminate the mental process behind reading a narrative and then making a moral judgment then perhaps we shouldn’t care so much about what happened when this guy in Belgium pretended to be electrocuting mice.

[Joshua Greene] says, Bostyn’s data aren’t grounds for saying that responses to trolley hypotheticals are useless or inane. After all, the mouse study did find that people’s answers to the hypotheticals predicted their actual levels of discomfort. Even if someone’s feeling of discomfort may not always translate to real-world behavior, that doesn’t mean that it’s irrelevant to moral judgment. “The more sensible conclusion,” Greene added over email, “is that we are looking at several weakly connected dots in a complex chain with multiple factors at work.”

Bostyn’s mice aside, there are other reasons to wary of the trolley hypotheticals. For one thing, a recent international project to reproduce 40 major studies in the field of experimental philosophy included stabs at two of Greene’s highly cited trolley-problem studies. Both failed to replicate.

I recommend reading the whole article.