The Rest Is Science - Would You Kill One Person To Save Five?

Episode Date: January 22, 2026

Can we store summer’s heat to warm our homes in winter? Could humans perceive a fourth dimension? And why does light bend around gravity even though it has no mass? Small questions from YOU which open doors to enormous worlds. In this episode of Field Notes, Hannah Fry and Michael Stevens discuss underground heat batteries in Canada and Einstein’s thought experiments, from how the universe hides its secrets and how we uncover them. Later, Michael presents a story which leads to an exploration of human behaviour, the experiments that reveal how authority influences our actions and why ordinary people can be pushed to act against what they say their values really are. Welcome to The Rest Is Science: Field Notes. Every Thursday, Hannah and Michael share the science behind the world around us from the surprising to the unsettling and show how it shapes both the universe and ourselves. ------------------- For more information about Cancer Research UK, their research, breakthroughs and how you can support them, visit ⁠⁠https://cancerresearchuk.org/restisscience⁠⁠ Cancer Research UK is a registered charity in England and Wales (1089464), Scotland (SC041666), the Isle of Man (1103) and Jersey (247). A company limited by guarantee. Registered company in England and Wales (4325234) and the Isle of Man (5713F). Registered address: 2 Redman Place, London, E20 1JQ. ------------------- Find The Rest Is Science all over the internet by ⁠⁠clicking here.⁠⁠ ------------------- Video Producer: Adam Thornton + Oli Oakley Video & Social: Bex Tyrrell Assistant Producer: Imee Marriott Producer: Becki Hills Senior Producer: Lauren Armstrong-Carter Head Of Digital: Samuel Oakley Exec Producer: Neil Fearn Learn more about your ad choices. Visit podcastchoices.com/adchoices

This episode is brought to you by Cancer Research UK. So when most people think of naked mole rats, their unusual relationship to cancer probably isn't the first thing that comes to mind. But maybe it should be because it is incredibly rare for them to develop cancer, which could be partly down to their unique immune system, or it might be the way that their cells respond to damage. So scientists are studying their biology for its cancer-fighting secrets. It's a reminder that discoveries can sometimes come from places

you don't expect. Cancer Research UK is the world's largest charitable funder of cancer research. Thousands of scientists of doctors and nurses work across more than 20 countries to help turn discoveries in the lab into new tests, new treatments and new innovations. And the impact is clear. Over the past 50 years, the charity's pioneering work has helped double cancer survival in the UK, meaning more people living longer, better lives free from the fear of cancer. information about Cancer Research UK, their research, their breakthroughs, and how you can support them, visit Cancer Research UK.org forward slash rest is science. Welcome to the rest is science. This is

field notes, a kind of podcast expedition diary where Hannah and I share some of the thoughts we've been carrying around, thrilling discoveries and big questions, whatever's been occupying our minds. I mean, some people call it thoughts. Other people call it burdens, but every week we're going to do I call it all I've got. Yeah, I mean, that's fair. We're going to bring something from a proverbial science mystery bag. We're going to bring something to show each other. It's like a rest of science's very own version of show and tell.

And yeah, this week it's your turn, Michael. That's right. And so later in the episode, I am going to share a story, actually. Oh. A story about the scariest moment for me ever. in the Mindfield Psychological Experimentation Show I did. And it's not what you're expecting. Well, I mean, you were the man who locked himself away for three days and started hallucinating. So if it's scary than that, then I think the rest of us need to buckle up.

As ever, we would also like to hear your questions, your theories, your thought experiments, maybe not your burdens. You can send them into us. And we'll dust off a shelf for you. You can join our vast collection of curiosities. Yeah, we'd love to put you there. So let's begin with Francois, who sent in a question. It seems such a waste to spend energy adding heat to our houses in winter and spending more energy on AC to remove it in summer. Could we feasibly design a machine that pumps heat into a form of reverse bridge during summer,

stores it, and then pumps the heat back into our homes in the winter? I mean, Francois, you have a mind that is a marvel, but unfortunately you've invented something that's already exists. because the machine you're describing is called a seasonal thermal energy storage system. And it's essentially, it's like a big battery but for heat. The problem is if you try and store heat, it leaks quite a lot, right? If you put a cup of tea and a thermist to come back the next morning, it's going to be cold, right? He has this habit of like sneaking away.

But there are some places where they do this. So there's a particular neighbourhood in Canada known as Drake Landing. where it gets really warm in the summer but also extremely cold in the winter. I mean, like that sort of part of the world has a massive variance in summer and winter temperature. And what they did there is they built 52 houses that were all connected to this massive underground storage field.

So in the summer, what they do is they have all of these solar panels on their roof and they use that to pump this solution basically down into this massive underground chamber where they have all of these boreholes and they literally heat up the rock that sits down there to about 80 degrees centigrade. And then in the winter when it's like freezing cold up top, they reverse the process. They pump water through these like very warm rocks and use it all to heat up their houses up top. You know, the London Underground is basically a perfect demonstration of the way that the earth Earth itself can hold on to energy in the form of heat.

I was going to say, that's impressive that the rock can hold the heat so well. This happens in the underground in London as well. Yeah, because right in the early days when the underground was built, it was like 10, 15 degrees, and they're the clay, the sort of London clay. It was actually quite cold down there. But after, you know, 150 years or so of all of these trains moving in and out of tunnels of people, of that energy being continually pushed in, it's sort of saturated. the heat capacity of the clay itself.

The clay cannot take on any more heat effectively. So all of the heat just continues to be down there. It can be 40 degrees down there in winter. You actually get more people fainting in the underground during winter than in summer when it is also insufferably hot. But in winter people are also wearing all of these like coats and things. So the earth itself is actually very capable of like holding onto working as this heat battery. It works really well in this place in Canada.

There's another example of Finnish company who've done this as well. They're using sand instead, this massive silo filled with sand. And they sort of heat the sand up to this crazy numbers like sort of 500 degrees C using renewable energy in the summer and then blow air through it in the winter to give them heat back. The only problem with this is that if you wanted to like, install one of these batteries yourself. If you want to say, okay, you know what, I can dig down. I could dig a kilometre down under my own house and have my own little battery.

That's what I think. I know. I know what you're thinking. This slight problem in this is that, I mean, it's the square cube law is going on here, right? Which is this. Actually, the surface area to volume ratio needs to be, you basically need to do it for a lot of houses simultaneously for the heat not to escape. You need like 50 houses at once.

But if, you know, if Francois, you happen to be a housing developer who wants to like heavily invest in minimizing energy bills for the future of your potential homeowners, then, I mean, this is a great way to do it. Just as long as you don't mind a bit of sand in your, in your water, in your shower. Or your air. Or your air. Exactly. Ah, turn on the dust storm. I'm getting chilly. Okay.

Next question. We had one question come in from Guy, from Slovenia, in fact, who said, do you think there will ever be a tool, an invention that humanity creates, which would let us gaze into a different dimension? Oh, wow. I love this question because it's, I hope so much that before I leave this earth, I get to look in a direction that isn't one of the three I was born into. So boring, looking in the same three directions the entire time.

I know. I think that there's so much more out there. I feel like Bell from Beauty and the Beast. It's just, I'm just this provincial 3D blob. And I desperately want to not look up down, left, right, forward, backward, but I want to look on Akata. And I think that, you know, things like, oh, we'll look in a history book. Then you're, you know, looking through time, a fourth dimension. I'm like, no, I want it to be spatial. And I think that the closest we are is, um, We can see the results, for example, of dimensional change. Look in a mirror. And every time you look in a mirror, you are looking at yourself as you would appear if you had been rotated in a fourth dimension through a fourth dimension. You can think about this as like an L shape. If this is stuck in a plane and it's moving around, it can never become this unless it gets rotated in a third dimension outside of the plane.

And if we do that to our bodies, we wind up just like this getting mirror reversed. So when I see my mirror image, I'm seeing what I would look like if someone from a fourth dimension grabbed me and rotated me out beyond these three dimensions that I live in. We have a lot of computer simulations that can simulate four-dimensional objects, right? There are a lot of amazing games that allow you to do this. But they only show you three dimensions. and then the object leaves for a little while or part of it leaves and comes back in

and you go, oh, it was transformed in more dimensions than I can perceive, interesting. But it's not just the effects that I want, it's the actual direction. And I feel like it's too late for me. I think that children might be able, if we catch them early enough, they might be able to see.

I think they're the tool. because they haven't been ingrained into the three dimensions yet. Like, you know how if you look at kids, they'll sometimes when they're learning to form letters, they'll write words backwards and mirror reversed. It looks like an amazing feat that would be hard for me to do as an adult. And they're just like, oh, yep, and they write their name. Everything's perfectly reversed.

Because to them, this and this are the same shape. Like they understand what is the same between an atiomorphs, between mirror image pairs. And we unlearn that as we become more familiar with the universe that we live in. I do have somewhere a four-dimensional Rubik's cube. Let me see if I can find it. I don't think I've put on my wall yet.

Let me look in the chill room, which maybe I'll show you guys one of these days. Chill isn't cold or chill isn't cool? Both. I'm so sorry. I don't know where the heck it is. it doesn't matter because I forget which kind of moves are allowed on it. So I would just make fooling myself.

But if you if you if you look up four dimensional Rubik's Cube, Melinda Green a long time ago made an interactive website where you can solve a four dimensional Rubik's cube. It can be rotated in the three dimensions we're used to, but also this fourth one that kind of turns it inside out. And it's phenomenal. And she's actually invented a physical version. and I've been talking to her about like how do we make more of these

and what would you do if you had, you know, more resources? And she's like, ah, I would put lines on them to represent the like geodesics and I'm very excited for it. That sounds really cool. I mean, impossible, but really cool. I do like the idea there of just getting a child as young as possible and then just being to them like demanding to point where the fourth dimension is because they're the only ones who can possibly know.

Exactly. They're the only ones. And from there, maybe guy, we could invent a tool to actually see it for ourselves. What if, though, what if we are like Bell? And actually, once we do get to the fourth or other dimensions, all that's to be found is beasts. But they won't really be beasts, but there will be Gastons who are afraid of that knowledge, that new vista that's been opened. And they will say, kill the beast, kill the fourth dimension. build walls to block it. And they may be right, but should they be right? Thing is, Michael, I think Beauty and the Beast was originally written as a little story that you would tell young, very young girls who are about to be married off to scary old rich men. To make them okay with it. It's like you think he's a beast because he is, but.

Maybe if you put in a lot of work, you can fix him. Well, look, the fourth dimension is my old rich man. And I am jumping into, I'm jumping into this relationship with both feet. Okay. Yeah. Give me the candlestick. I'm a teapot and off again. Okay.

Amazing. Let's move on to a question from Henry. Why does gravity bend light if light has no mass? It's a great question, isn't it? It's a great question. Yeah. And the thing is, is that that doesn't make any sense if you stick to Newton's idea of what light is, of what gravity is, sorry, that it's like it's something that acts on mass. But Einstein's version of gravity is that it's not the light that's bending.

It's the space around the light that is bending. And that is why it appears to bend. It's not that it's like having a gravitational pull or gravitational effects. And I know that actually we did this whole episode on gravity and we talked about. there's still a slight problems with imagining it as though it's a bowling ball on a rubber sheet, which is the one that sort of people talk about quite a lot. But there's a slightly simpler way to think about this, I think. Imagine if you're standing in like an elevator in a lift and you've got a laser and you're

sort of pointing the laser over at the other side, hitting the wall directly opposite the elevator. And then all of a sudden there's like a rocket engine under the elevator that blasts off. accelerating the elevator up extremely fast. Now, the thing is, is that while the floor is rushing up, while the light is travelling across the room, the floor underneath it is rushing upwards so quickly that it means that by the time the light hits the wall, the wall will have moved up. So to you, standing on the inside of the elevator, it looks like the laser beam is curving downwards, because you're moving up incredibly fast. And what Einstein realized essentially, that's like the bending of the light, as it were.

And what Einstein realizes that acceleration feels exactly the same as gravity. There's those two things, the feeling of them, as it were, is sort of indistinguishable. If you wake up in a windowless box and you feel heavy, you don't know whether you're on Earth or whether you're in a rocket that's accelerating at 1G. And so if acceleration can bend light, then gravity must also bend light. And the proof of this came in, like the really remarkable proof was of Einstein's idea. years came in 1919. It was a big eclipse. For years it was just this cool theory, right? But then this total solar eclipse happened. And astronomers, they, in 1990, went to the site of the eclipse and they looked at stars that were directly behind the sun. Now, if light didn't bend, then during the

total eclipse, you shouldn't be able to see them. Right? You'd have to wait for different moments in the year, different times to be able to see those stars. But because the sun's gravity bends the light from those stars around, during the total solar eclipse, those stars appeared next to the sun. And the position of them, the position of those stars was shifted by exactly the amount that Einstein had predicted. So, and that experiment, that was what really made Einstein this, this celebrity overnight. Superstar. Yeah. Superstar. Yeah. He proved. that light doesn't need mass to be pushed around. It's, it just needs this, this road that it follows.

Yeah, the space time that it travels through is being curved. And the light is just traveling in the geodesic, the straight line path. And, whoops, it happens to be curved. Guess I went around the sun into your eyeball. Peekaboo. This is really why Einstein has the reputation that he does. This is why everyone is still, you know, 100 and whatever years later, still so completely flawed by the.

unimaginable foresight of this man. Like to be able to sit in a room and have a thought experiment like that elevator and conclude from it that during a total eclipse, you should still be able to see the stars that are hiding behind the sun and then ending up being correct. I mean, that really is just phenomenal. I mean, that's the dream. Your ideas are testable. They are tested in your lifetime.

And you were right. You predicted things we had not observed before. Absolutely. Well, okay, from predicting things that have not been observed before to hearing stories that have not been told before. Join us back after the break. This episode is brought to you by Cancer Research UK. We often think of beating cancer as treatment, but imagine stopping it before it begins. After years of work, Cancer Research UK scientists are launching a clinical trial of lung vacs, the first vaccine designed to prevent lung cancer. It builds on TracerX, the world's largest cancer evolution study,

which tracked lung cancer cells over many years to uncover the disease's earliest warning signs. Lung Vax is designed to train the immune system to spot these signs early on, destroying faulty cells before cancer develops. So it's not treatment, but preventative, with the potential to stop lung cancer before it starts. The first stage of the trial starts this year focusing on people at higher risk. It shows what long-term research makes possible. For more information about Cancer Research UK, their research breakthroughs and how you can support them, visit cancerresearchukuk.org forward slash the rest is science.

All right, welcome back. Hannah, have you ever had your mind experimented on by scientists? Not knowingly. Well, good. One of these days I'd like to do some on your brain, but today I want to talk about the scariest experiments I've been a part of. I did this a lot in college for money. You could go in and make a few bucks by taking a survey, or you could make dozens of bucks by having them do an MRI scan on you. Are you one of the weird people that they talk about, the idea that psychology experiments are largely done on a particular type of person?

Exactly. They're done by college undergrads who want five bucks to get a big neck, you know? And so, yeah, I was one of those people that like the foundations of psychology are built on and continue to be built on. And I remember one time I did this MRI study and while they calibrated the machine, they had me watch a movie and I could pick a movie. And it was clear that they had three movies to choose from. One was for women. One was for men. And one was for men. And one was. was for children. And the movie for children was Airbud. And I've never seen Airbud. So I'm like, yeah, I don't do Airbud. So I'm watching Airbud in this MRI machine while they calibrate the magnets to my brain. And the amount of time it took for them to calibrate the machine was the amount of time it takes for the kid in the movie to realize the dog can play basketball. So I got to watch everything but the dog play basketball. And I was so upset. It wasn't worth the 50 bucks I got paid. And I'm still mad about it. I still haven't seen Airbud. Did they not give you the option to continue the film?

No, they were like, all right, now the experiment must commence, and I had to like recognize patterns and stuff. And I'm like, please put the dog back on the screen. Now, I've seen clips of the dog playing basketball, and I did a whole episode about whether or not a dog could play basketball, according to the rules of the state that the movie appears in. I won't spoil it, but the conclusions were quite surprising. Anyway, psychological experiments is what we're talking about.

When I was in high school, I had a psychology teacher that got me into psychology. It's why I studied psychology in college. But all he really did is play us videos. He played Candid Camera Clips and then would talk about the psychology that was part of the prank we were watching. You know, Candid Camera is a TV show where people get pranked. Pranks are a big thing on the internet now. And they can be amusing. They can sometimes be cruel.

but often, almost all the time, you're learning a lot about how humans behave and how we think. So I envision doing a prank show that was actually psychological experiments. Because so many experiments on human psychology are basically tricking people into thinking one thing and seeing what they do. And so in Mindfield, we did a lot of experiments that were, you know, pretty intense. We actually recreated the trolley problem. Right. We developed this intense ruse where people thought they were coming in to review these new high speed rail car interiors, right? Is the fabric soft or the color's good?

It's the lighting good. But then there was a delay and they had to go and wait in this air-conditioned room because it was a hot day. There was a switching room. And this old man that we hired who used to switch railroad cars, like teaches them, yeah, I have to switch the lines because these guys are coming to work on it and whatever. He shows them. And he's an affable guy. and they get to do it themselves while they wait. And then he has to leave the room and boom, the trolley problem happens.

And the trolley problem being the idea that the question normally theoretical, but apparently not in your case, of whether you, there is a trolley, careering down a track and is set on a path where it's going to kill five people or whatever it might be. And you have the choice to pull a lever to redirect. the trolley, the train, as it were, so that it only kills one. The question is, do you do it? Yeah.

So, so what would you do? So it's really, I mean, the whole point of this, this, like, theoretical thought experiment was to demonstrate how sometimes there isn't a clear answer to an ethical question. Because if you take the utilitarian approach, right, which is like, count up how many lives are saved, then, then you say, well, obviously you should pull the lever. You know, there's five people on, if you do nothing. thing and then there's one person if you if you pull the lever but then I mean then there's also like the sort of value ethics the value based ethics which says okay but the the murder you are effectively

murdering somebody because it's your intervention which is choosing somebody's death you're choosing to intervene in a situation and the the person's death is a direct consequence of that I personally I don't know why I would do in that situation I think I would really I think I would struggle to pull the lever if I'm honest yeah it's a struggle because Because yes, if I pull the lever, then only one person dies, not five. But they died because of my action. I feel a lot more responsibility over it. I've got to talk to that person's family and say, yeah, they would have been okay if I hadn't

done it. I did save five people. But what had never been done was testing it in real life. If you actually put people in that position. So there were CCTV cameras broadcast all over this switch room. So you could see the tracks. And you could see that a worker went on to the side track while five were working on the regular track. And the authority figure, right, the guy who's employed to switch the tracks has left.

And these alarms start going off. Like person on track, train approaching, train approaching. What do you do? And as it turns out, people don't do anything. They freeze. There's fight or flight, but there's also freeze. And that is the most common. behavior that we saw. Now, we had to have an actual psychiatrist on set to debrief people

to tell them, everyone's okay, this was all not real, and the decision you made is not something that should bother you. You know, you really helped science today because people were really broken up about the fact that they did nothing. And we needed to make sure, and we followed up with them a couple of weeks afterwards, because you don't want to traumatize people into thinking, I'm the kind of person who wouldn't pull the lever. I allowed five people to be killed instead of one. So it's a really serious thing. But that's it.

You're learning. You are learning something about yourself. You're learning something about yourself. And so we had to sit down and tell every person afterwards, you know, first of all, obviously, everyone's fine. Those are all actors. You were watching pre-recorded segments where no one was in danger. But the decision that you made is the right one. You know, there is no decision that is fair.

And to put you in that position was not fair. So you shouldn't leave thinking, oh, I did the wrong thing. But that wasn't the scariest episode for me, because I just got to watch people do it. For me, the most fear I felt, it wasn't when I went to Peru and drank ayahuasca with a shaman in the middle of the rainforest. It was a experiment we did in partnership with Philip Zimbardo. the guy who was behind the Stanford prison experiment where a bunch of college students were taken in during the summer and some were assigned to be guards and some were assigned to be prisoners

and they started treating each other so badly, like physically, abusively that he had to end the experiment. And he was like, holy cow, if you give people authority and no oversight, they just abuse it. It's a famous experiment, which we did a whole episode on. But we also did one on how to make a hero. And we wanted to test if people would truly, become a whistleblower. If we put people in a situation where something was being done that

was wrong and it was up to them to stop it, would they? If you ask in a survey, 95% of people say, of course, I would come forward. But in real life, it's a lot more complicated. And so we rented out a wing of a psychology department at a university in Los Angeles and posed as real experimenters. and we were bringing in people to place phone calls to get us subjects for the experiments. And we told them, you know, we're looking at isolation. We're going to put people in isolation for 10 days. Now, in the show, I had done three days. And that is around the maximum where someone starts to lose their grip on reality.

There's a lot of anxiety and fears and also just depression, feelings of your life isn't worth it. And we told this to these recruiters and we said, yeah, it's really dangerous. You know, here's a list of all the things that could go wrong and all of the like mental problems that could be caused by it. But it's important for science that we do this. And during the informative sessions, like half of the people in that room were Confederates who worked for us. and that was for part later in the experiment. I also receive a phone call at some point during the orientation where I'm told that the experiment has not been approved

by the university's ethical review board and that it cannot continue. So at this point then, the people who you are, who are on Candid Camera effectively, they know that this is not good and not only that is not approved. It's not approved. And they overhear this conversation because part of it's on speakerphone and then I switch it.

And then I say, look, I'll deal with this later. Like, we need to start doing this now. And every single person agreed to go ahead and phone bank for me to get recruits. And we had them call actors who were trained to ask, like, is this safe? And the recruiters just like, they worked for me. They lied. And they said, oh, yeah, no, this is really safe. and you're going to be fine, and it's going to be like a vacation.

And they actually lied or they can see, I mean, were they like, I guess there's like a spectrum of lying, right? Like, were they just sort of concealing and saying they didn't know or were they actually lying? Most of them didn't directly lie. There were some who were almost happy to say, yep, this is like probably even good for you. Others, they lied in really interesting ways where they would say, they would be asked, what are the, what are the, what are the, risks involved. And they would say, well, there's nothing toxic. There's no electric shocks. They just mentioned true things that weren't a problem to avoid mentioning the actual known problems of forced isolation. And we then had our Confederates come in and say, hey, I'm starting to feel

bad about this. I don't think we should be doing this. To give the real participants an opportunity to say, yeah, I'm leaving or I'm going to make a phone call, right? And this was all filmed on hidden cameras. How many of them did? How many of them said that they wanted out? None. Still no one said anything. They just said, well, you know, it's what we're hired to do, basically.

And then we had a woman come in to the rooms where they were, the cubicles where they were doing the phone calls who said she was from the ethical review board and wanted to know what they were calling about. and they all confessed that it was for the experiment involving isolation. And we did this for two days, and only one person agreed to go on record accusing me of violating the Ethic Review Board's decision. Everyone admitted that they were doing it and that it was wrong and that they felt bad doing it, but they just wanted to not be a part of it. first of all, there's a million things going on here. Was it loyalty to me?

Was it dedication to the job they were hired for? The most common rationalization was that it was important for science that we do this. And that was also what Stanley Milgram heard the most from his participants when he, many decades ago, asked people to administer electric shocks to participants that weren't real, but they thought were real. When asked why did you go ahead and do what the experimenter said and shock people so badly, they said, well, it was for science. It was for learning. It was worth it. I mean, the background of that Stanley Milgram experiments is, I mean, darker still. It was after the Nuremberg trials when Nazis were accused of participating in this horrific moment in history of participating in the deaths of millions of people. and people's defense was, well, I was just doing my job.

And the Milgram experiments were to say, you know, how far will people go? How far will people harm each other if they're told to do so by somebody in a white coat and a clipboard? And it turns out very far. They'll go very far. Even for something as simple as like a minimum wage phone banking job to recruit test subjects, it's almost like it's hardwired into us to be loyal to the, the job and do what we are told by authority. And in a lot of ways, I think the guilt can be diffused onto the system that's asking you to do it.

Look, I'm just a small part in this. Like, it's not really up to me. I don't want to lose my job. I don't want to get in trouble from my employer. So I'll just go ahead and tell people there are no known risks. And everyone did it. It was scary for me because I had to be. the unethical experimenter.

I had to answer the recruiter's questions when they said, well, when are you going to tell people that this is dangerous? And I'm like, oh, we'll debrief them afterwards on the known risks. Afterwards, and I had to pretend like this didn't bother me. And I want to be liked. I think it's part of being a YouTuber. I just am a people pleaser. and I really, really had a hard time psychologically with two days of being evil.

But then having no pushback. Only one person ever pushed back and never to me. They told the authority figure my boss who showed up. They told her, yeah, he shouldn't be doing this. And yes, one person said, I will go on record and say that I did this and that I was told to do this. I wonder whether we should do a whole episode on that Milgram experiment and talking about the sort of tendency of humans in more detail, because I think that the research on it is absolutely fascinating. And it feels quite dark in a lot of ways that actually once you have that

that intersection of like moral responsibility, but with sort of financial reward, with like societal expectation, with like systems and norms, actually, we really do struggle to buck the trend and stand up. I mean, it reminds me quite a bit of the bystander effect. Yes. Which is this idea. I mean, it's not quite as bad as I think the very, the first sort of tellings of the bystander effect made it sound really horrific.

There's like this paper in the 1960s that said somebody was stabbed to death in New York and 38 people saw it and nobody did anything. Kitty Genevies, yeah, a real murder with witnesses all. around and not a single person called the police or intervened. But I think over time, actually, that idea of 38 people watching on was a little bit of an exaggeration. And I think that a couple of people had actually called the police. It was sort of, it was a bit of an exaggeration by journalists. But you do see this bystander effect in the psychological experiments that you're describing where you get people, in particular when you have smoke filling in a room and actors that are not reacting,

people sort of assume that it's not really their problem. Or you have some students who are sort of sitting in a room and over an intercom they hear the sound of somebody else having a seizure or crying for help or something and very, very few people will intervene. But it's sort of like people can reason that this isn't their problem, that there's somebody else who will step in and fix it. Yeah, the seizure one, I remember an experiment where people were doing some task that was obviously just a filler task over headphones.

Everyone was in their own little cubicle, and they heard the people they were working with over headphones. And in one condition, there were like four people all listening together and talking together, and then the other people were alone with just them and one other person. And if the other person they're listening to faked having a seizure or a heart attack, the other person listening immediately got up and went for help. But if they believe there were four people on this line and one of them had a heart attack,

they would just keep sitting there for a while because surely someone else is going to do something. Right. The thing is that, I mean, in these experiments that sort of because it's a lab setting, because it's sort of a constructed setting, when you watch back videos of genuine disasters, right, so real emergency situations, kind of real high stakes scenario, actually, I mean, you often do see people who step up. And I think that the original idea of the bystander effect is that the more people that there are, like on your phone call, the more people there are, the less it's my problem to do something. Whereas I think in situations where you have, I don't know, like someone wielding a knife, for instance,

actually the more people there are, the more likely it is that people will step in and try to mount a response. It's much less scary when you feel as though there's sort of safety and numbers. So it's maybe not quite as depressing as sometimes the telling of this. But there is still something in there, though, right, of like personal responsibility versus collective responsibility. I also wonder whether there's like a international dimension to this. The trolley problem that you described right at the beginning, one of the most fascinating experiments that I've seen done on the trolley problem was in the sort of the early excitement

about driverless cars, maybe around 2018 or so. there was a group of scientists who set up an online game where you could go and play the trolley problem with a driverless car, but it would give you lots of different options. So your driverless car could run over five people or one person, the traditional version, or it could run over a couple or an old granny or a cat or a mom and a baby and so on and so on and so on and would present you with these problems. And what was completely fascinating about that was the breakdown of how different cultures valued different things, how different things. how some cultures, particularly in Japan, really cared a lot about older people, would sort of would prioritize them right at the top, whereas other cultures, Western cultures, for instance, cared about children much more. Everyone cares about cats. That's, I think, the other thing that came on bit. But we should definitely do some episodes digging more into your psychology past. Well, yeah, because there are just so many factors. Yeah, people in groups can be better, but they can also be worse than they are alone.

And what factors cause it to go one way or the other we're still learning about. And we also still have open questions about the hypotheticals themselves. How valid are they? Because in a lab setting, it's very different than real life. If you're programming a autopilot car

to, you know, favor young couples with a baby over old people, is that really a real choice in real life? Because in real life, what the car will do is it will stop itself, it will drive off the road, it'll crash itself into a wall. Like there's always some other option that isn't the simple, this person or that person. I always thought it was really interesting how,

if you're following the trolley problem logic, you want the car to crash itself rather than crash into people. But who's going to buy a car? Who will buy a car that will crash and potentially hurt the people driving it rather than other people instead. Exactly. Yeah. Yeah, we haven't talked about the train.

What's it carrying? What if it's got, you know, 12 people on it? What if it's got a million embryos on it? Actually, Amy, one of our producers, she's just pointing out that there's this idea of inflicted insights, you know, the idea that there's trauma to learning something about yourself that you can't unknow and that psychologists really started to discuss this a lot after the Milgram experiment.

Inflicting insight. What a great phrase. Yeah, we encountered that so often in Mindfield. And I encountered it personally. The reason I disliked how to make a hero was that I learned how easy it was to get away with bad stuff. Right. I think we live our lives thinking, oh, I couldn't do that. I'll get caught. But then here I am, literally being an evil, manipulative scientist, and everyone's just eating it out of my hand. Like, yeah, of course. It's interesting that idea that being powerful and evil made you feel uncomfortable. Sometimes I do this thing where I'll like have a day or two where I will deliberately not get out of the way of anybody when I'm walking down the road. Hannah. Have you ever tried this? No, I'm not a sociopath. Like go down Oxford Street or something,

like a really, really busy, busy road and just like, I'm not getting out of the way. And everybody does, move around you. It's like you feel so powerful and so evil and I can't keep it up. But it's fun to do for like a moment and then, you know. I think it's probably a good lesson that yeah, we are a lot more powerful than we think and allow ourselves to be, maybe for good reason, but it's fragile that the barrier between the two. Well, there you go. We've learned about some of the scariest things on the planet there then, Michael, which is ourselves. So if you've got any questions that you would like us to answer. You can send them in at the Restis Science at gohanger.com. And you can join our newsletter at the rest is.com slash science. We are going to be back

next Thursday with another edition of field notes. And on Tuesday with our normal episode, until then. Stay curious. Bye-bye.