What Do People Really Do in a Realistic Trolley Dilemma Experiment?

You are walking along the tracks of a trolley in San Francisco.  You see a runaway trolley that will kill five people who have become somehow bound to the tracks.  You also see that there is a switch that will turn the trolley onto a side track, a spur, and thus save the lives of the five people.  Unfortunately, however, there is one person bound to the side track, and so if you throw the switch, he will be killed.  Should you throw the switch?

On another day, you are walking on a footbridge over the tracks.  You see another runaway trolley speeding toward five people bound to the track.  This time, there is no possibility of switching the trolley to a side track.  You could jump onto the track to try to stop it, but you are such a small person that you probably could not stop the trolley.  You notice that there's a big fat man on the bridge who is big enough to stop the train if you push him onto the track.  Should you push the fat man?

Oh, I know, this runaway trolley scenario sounds too cartoonish to be taken seriously.  But it does capture the moral dilemma that people can sometimes face--perhaps in war--when it seems that some people must die to save the lives of many more.  Although killing someone is usually wrong, there are circumstances in which killing is justifiable--such as killing in self-defense or in defense of the lives of others.

Of the hundreds of thousands of people all around the world who have participated in formal Trolley Dilemma surveys, most people (80% to 90% in some studies) would divert the trolley in the Switch Case, but most of them (around 75%) would not push the fat man in the Footbridge Case.  As reported by Paul Bloom (in Just Babies, 167-68), even three-year-old children presented with the trolley problem (using Lego people) will tend to say that throwing the switch is right, but pushing the man off the bridge is wrong. What is most striking about this is that most people react differently to the two cases although pulling the switch and pushing the fat man have identical consequences--one person dies to save five.  Why?

Joshua Greene thinks that if you scan the brains of people with fMRI while they are deciding this Trolley Dilemma, you will see the neural activity that explains why people decide this the way they do; and this will reveal the neural correlates of moral judgment.  Previously, I have written about the Trolley Dilemma (here and here) and about Greene (here, here, and here).  Recently, I have been thinking more about this as possibly showing how conscience and guilt arise in the brain.

But right now I am wondering whether what people say they would do in the hypothetical Trolley Dilemma situation shows us what they would actually do in a real Trolley Dilemma situation.

As far as I know, the first realistic Trolley Dilemma experiment was done by Michael Stevens for his "Mind Fields" YouTube video series here  It's about 35 minutes long.  This video is entitled "The Greater Good," and it was Episode 1 of the second season, which first appeared online December 6, 2017.

The experiment is clever.  Seven people were recruited to participate in a focus group for the "California Rail Authority" (a fictitious organization).  They think they will be asked questions about what they would like to see in high-speed rail transportation.  When they arrive for their meeting, at a CRA trailer on a hot day, each individual is told that there is going to be a 15 minute delay, and while they are waiting, they can sit in an air-conditioned remote railway switching station.

Inside the switching station, they meet a switchman who sits before a panel of screens with (apparently) live pictures of a remote railway switching location.  The switchman explains how he switches a train from track 1 to track 2.  A train is coming through, and he has the duped subject actually switch the train onto track 2.  Then the switchman receives a phone call, and he says he has to leave for a short time, but the subject should stay in the switching station.  What the subject does not know is that what he sees on the video screens is all prerecorded, and the switchman is an actor.  The subjects do not know that everything they do is being filmed by hidden cameras.

Sitting alone in the switching station, the subject sees railway workers walking onto the tracks, and hears a loud warning "objects on the tracks."  One worker walks onto track 2, and he appears to be distracted by taking a telephone call.  Five workers walk onto track 1, and they are wearing sound-proofing earphones.  All the workers have their backs turned to the train that is shown approaching, and the subject sees this train coming and the warning "a train is approaching" on track 1.  The workers do not seem to see or hear the approaching train.  So the subject must think that the 5 men on track 1 will be killed unless the train is switched onto track 2, so that 1 man will be killed.  Should the subject pull the switch?

You might think this is an unethical experiment.  Isn't it wrong to trick people into going through such a traumatic experience?  After consulting with psychologists, Stevens decided this would be an ethical experiment as long as they screened the people they recruited and excluded those who showed the personality traits that might predispose them to be excessively traumatized by the experiment.  He also designed the experiment to minimize the traumatic effects.

7 individuals went through the experiment.

The first was Elsa.  When she was left alone in the switching station, and she saw the train approaching the men on the tracks, she became visibly disturbed as she intently stared at the screens.  Just a few seconds before the train would have hit the 5 men on track 1, she switched the train onto track 2, expecting that the one man would then be killed.  But as soon as she pulled the switch, the screens went blank, and this message was flashed on the screen:  "End of test.  Everyone is safe."  She did not actually see the man on track 1 being hit.  And immediately Stevens and a psychologist entered the building and told her that this was all an experiment, and all these people were actors.

They asked Elsa about what she was feeling and thinking.  She was frightened by what she saw on the screens.  "Their lives are in my hands," she thought.  "I must save more lives."  "I didn't know if I made the right decision. . . . But a life is a life."

When people are asked to make a decision about flipping the switch in the hypothetical Trolley Dilemma, most of them agree with Elsa and decide to kill one person to save five.  Surprisingly, however, in this experiment, in which people thought they were really deciding life or death, most of the participants--5 out of 7--refused to flip the switch.  The five people that came after Elsa all froze in fear as they watched the train approaching the men, and so these five refused to flip the switch.

Afterwards, each of the 5 said that they felt terrified, and they froze up so that they could not move their hands to the switch.  "I thought about it, but I couldn't do it," one said.  They all suggested that they had fleeting thoughts that surely the men would somehow escape from being killed.  Surely the workers would notice the train and jump away.  Or maybe the train had sensors that would stop it to avoid hitting them.  Or maybe there are other railway people watching over this scene who can stop the train.  They were looking for some way to escape the tragic inevitability of the choice between one dying and five dying.  One person said: "I didn't know who should live, who should die. . . . Switching or not, someone would be hurt."

The last of 7 in the experiment was Cory, and like Elsa, he flipped the switch.  But we see and hear him talking to himself: "Oh no. . . . They should see this. . . . Oh my God!"

We see the terror in Cory's face, and afterwards he expresses how horrified he felt in taking responsibility for his decision.  "5 people versus 1," he says.

Cory burst into tears once Stevens and the psychologist came into the building.  He was clearly distraught by what he had done.

I know we probably shouldn't draw conclusions from an experiment involving only 7 individuals, but I will go ahead anyway and draw three conclusions.  First, this experiment suggests that for most people, what we think we would do in a moral dilemma like this differs from what we would actually do.  Most of us decide the hypothetical Trolley Dilemma by saying that we would flip the switch, and thus endorse the utilitarian calculation that taking one life to save five is the "greater good."  But if we were in a real tragic situation like this--or one that we thought was real--most of us would freeze, refusing to kill the one man to save five.

If this is so, how do we explain it?  Was there something about Stevens' experiment that made the flipping of the switch feel like a "personal" harming of the one man on track 2--making it feel more like the pushing of a fat man off the footbridge into the path of the train?  If Stevens could have scanned the brains of these 7 people during the experiment, would he have seen that the more emotional parts of the brain (amygdala, posterior cingulate cortex, and medial prefrontal cortex) were active, countering the more calculating parts of the brain (the dorsolateral prefrontal cortex and the inferior parietal lobe), which is what Joshua Greene and his colleagues in 2001 found in the brains of those deciding the Footbridge Dilemma?

Was there something about the circumstances of Stevens' experiment that made at least five of the seven people feel that flipping the switch would violate the instinctive moral principle of double effect because they would be directly targeting the man on track 2 for death?

My second conclusion is that in a tragic dilemma like this, there is no right choice.  That's what makes it tragic!  So both those who pull the switch and those who don't can feel justified.

Here I seem to disagree with Stevens.  In his closing comments, he asks the question, Is it wrong to freeze?  And he implies that the answer is yes, because he says we can learn to overcome our propensity to freeze to serve the "greater good."  Both he and the psychologist appear to praise Elsa and Cory for having made the right choice.  But I don't see that.  And in the meeting of all the participants at the end, they share their experiences in a way that suggests that those who froze need not feel ashamed of their decision not to throw the switch.

My final conclusion from this experiment is how is shows both reason and emotion in moral judgment.  These 7 individuals had only a couple of minutes to decide the shocking moral dilemma they faced.  But in that short time, they all showed deep emotional disturbance, and they all engaged in some reasoning.  They all assessed the situation emotionally and rationally before making their decision.  This teaches us a general truth about human nature--the moral judgment is both rational and emotional.  But it also teaches us about the individuality of moral decisions in which different people will come to different decisions where there is no clearly right answer.