A train is heading toward five people who can't escape its path and only you are close enough to do anything.  You can reroute the train onto different tracks with only one person along that route.

Would you do it?

A team of Michigan State University researchers recently put participants in a 3-D setting and gave them the power to kill one person (in this case, a realistic digital character) to save five. The results of the moral dilemma?  About what you would expect. 90 percent of the participants pulled a switch to reroute the boxcar, affirming that people are  okay to take a direct hand in killing someone if it saves a lot more, even if they are against killing people.

Evolutionary psychologist Carlos David Navarrete thinks there is a deeper issue that can be explored in this twist on the "trolley problem," a moral dilemma that philosophers have contemplated for decades. This is the first time the dilemma has been posed as a behavioral experiment in a virtual environment, "with the sights, sounds and consequences of our actions thrown into stark relief," the study says.

Does better virtual reality make the difference? Maybe. Certainly there are arguments about the impact of violence in media on children and some in Hollywood are convinced that any smoking in a film leads to more smoking.  The research participants were presented with a 3-D simulated version of the classic dilemma though a head-mounted device. Sensors were attached to their fingertips to monitor emotional arousal.  The results were the same as when this test was done for decades without 3-D glasses on, though, so it seems a little gimmicky.


A 3-D simulated version of the classic "trolley problem." Essentially, they had to decide whether to kill one person to save five. Credit: Michigan State University

In the virtual world, each participant was stationed at a railroad switch where two sets of tracks veered off. Up ahead and to their right, five people hiked along the tracks in a steep ravine that prevented escape. On the opposite side, a single person hiked along in the same setting.

As the boxcar approached over the horizon, the participants could either do nothing – letting the coal-filled boxcar go along its route and kill the five hikers – or pull a switch (in this case a joystick) and reroute it to the tracks occupied by the single hiker.

Of the 147 participants, 133 (or 90.5 percent) pulled the switch to divert the boxcar, resulting in the death of the one hiker. Fourteen participants allowed the boxcar to kill the five hikers (11 participants did not pull the switch, while three pulled the switch but then returned it to its original position).  The study also found that participants who did not pull the switch were more emotionally aroused. The reasons for this are unknown, although it may be because some people freeze up during highly anxious moments – akin to a solider failing to fire his weapon in battle, Navarrete said.

"I think humans have an aversion to harming others that needs to be overridden by something," Navarrete said. "By rational thinking we can sometimes override it – by thinking about the people we will save, for example. But for some people, that increase in anxiety may be so overpowering that they don't make the utilitarian choice, the choice for the greater good."

Published in Emotion.