Known but not felt

Inside a modern car you do not hear the cyclist shout, you barely see the face of the person you cut off, and a near miss does not reach your body the way it would on foot. The car is not making anyone crueller. It is absorbing signals, and a large part of what stops people hurting each other at the moment it happens may be those signals rather than anything they know or believe. A machine can leave the knowledge intact and remove the feeling. And the first thing a car hides from a driver is not another person. It is the driver's own act.

The clearest evidence is old. In Stanley Milgram's obedience experiments at Yale, an experimenter told a volunteer to give increasingly strong electric shocks to a "learner", in fact an accomplice, whenever he made a mistake on a memory test.¹ In one series Milgram varied only how close the learner was. In the Remote condition he sat in another room, unseen and unheard except for pounding on the wall at 300 volts.¹ In Voice Feedback his protests came through the wall. In Proximity he sat a foot and a half from the volunteer. In Touch-Proximity the volunteer had to force his hand onto a shock plate.¹ Forty men took part in each condition.¹

The share who defied the experimenter rose with each step: 34% in Remote, 37.5% in Voice Feedback, 60% in Proximity and 70% in Touch-Proximity.¹ The obvious explanation would be that closer volunteers understood the learner's suffering better. Milgram checked, and they did not: there were no consistent differences across the four conditions in how much pain volunteers thought the learner was in.¹ At a distance, he wrote, the suffering "is apprehended, but not felt."¹ One volunteer in the Remote condition said, "It's funny how you really begin to forget that there's a guy out there, even though you can hear him."¹

Volunteers also made distance for themselves. In the pilot studies, people often averted their eyes from the person they were shocking, and one explained, "I didn't want to see the consequences of what I had done."¹ They kept giving the shocks.¹

Milgram did not claim to know why closeness worked. He listed several possibilities: cues of pain that trigger empathy, the discomfort of being watched by the person you are hurting, and how hard it is to experience pressing a lever in one room and a scream in another as a single act.¹ Distance removes all of these at once, and so does a car cabin: it muffles the other person, hides the driver from them, and separates the action from its result.

The first thing hidden is the act

Before any other person is involved, a quiet car hides speed. A 2024 review of the research on in-car sound summarises it plainly: removing or reducing engine sound "leads drivers to underestimate speed and, consequently, to drive faster."² The studies are mostly in simulators, often with young men, and the authors call the field "scarce and rather outdated", partly because industrial research is rarely published.² They also note that the studies that exist on the sound of electric cars mostly concern its pleasantness and comfort rather than whether drivers can judge their speed.²

That is the general pattern in miniature. The signal that told the driver what they were doing was treated as noise, and removing it was an improvement by the measures being used. No one decided that drivers should feel less of their own speed; it followed from designing for quiet.

Not distance but feedback

Milgram's own example of the remote case was the bombardier, who knows his weapons will cause suffering and death but whose knowledge is "divested of affect".¹ If physical distance were the variable, the most distant crews of all would be the least affected. The evidence on drone crews points the other way. In a 2019 survey of 715 US Air Force drone crew members who had been exposed in real time to at least one traumatic event, 6.15% met the criteria for post-traumatic stress symptoms.³ Among the significant predictors was the number of times they had watched civilian bystanders being killed by enemy forces, or felt shared responsibility for bystanders' injury or death.³ An earlier survey of 1,084 operators by the same lead author found 4.3% meeting the criteria, against 10-18% among military personnel returning from deployment.⁴ Both surveys were led from the US Air Force School of Aerospace Medicine, studying the service's own crews.³⁴

Drone crews are remote from the people they watch, and they watch in real time.³ What the bombardier lacked was not nearness but a picture. Feedback can cross any distance, and can be removed at arm's length.

What this asks of design

If restraint runs on feedback, the moral question about a machine is partly an engineering one: which signals does it pass through to the person operating it? The engine-sound review is about one small instance, and it points to a design answer: sound shaped so that a cabin stays quiet while the driver can still tell how fast the car is going.² Whether a sealed cabin also changes how drivers respond to other people, to the shout, the face, the flinch, is the seed's own claim, and it is still a hypothesis.