Why You Should Stop Using Face ID

Do you think your thoughts belong to you? How would feel if you found out they don't? In this episode Hannah and Michael discuss a tangible future where the last bastion of privacy is breached and the thoughts that run through out heads no longer belong to us. Why is it that in 2026 police can open your phone using face ID any time they want, but they can't do the same with your password? When might a single brain wave called P300 eliminate the need for evidence in court? And how do we protect the contents of our minds now that we're imaging dreams, translating thoughts and installing brain chips? Find out on The Rest Is Science. ------------------- 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 + Jack Meek Animator: Sam Benson Video & Social: Bex Tyrrell Assistant Producer: Lucy Lipscombe Producer: Simona Rata Senior Producer: Lauren Armstrong-Carter Head Of Digital: Samuel Oakley Exec Producer: Neil Fearn Learn more about your ad choices. Visit podcastchoices.com/adchoices

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:01Hannah Fry?

  Welcome to The Rest of Science. I'm Hannah Fry.

• 0:02Michael Stevens?

  And I'm Michael Stevens. Right now, I'm thinking in a legal thought.

• 0:08Hannah Fry?

  Uh-oh.

• 0:09Michael Stevens?

  Or am I?

• 0:10Hannah Fry?

  I can't tell.

• 0:11Michael Stevens?

  You can't tell. I could be committing all kinds of crimes up here right now.

• 0:15Hannah Fry?

  But is it to think it to commit the crime?

• 0:17Michael Stevens?

  That's what we're going to talk about today. We're going to talk about the power of thoughts, the responsibilities you have as a thinker, and whether you have any. Can you own a thought?

• 0:27Hannah Fry?

  Can you be punished for it even?

• 0:29Michael Stevens?

  Should you be? I want to talk about this today because I read a few weeks ago, like, a startling fact, which is that the police are allowed to collect evidence from you by unlocking your phone if it has Face ID or fingerprint recognition encrypting it. But however, if you lock up your phone with a passcode, they can't get into it legally.

• 0:51Hannah Fry?

  What? So wait, hang on, I need to understand this. So if you've got Face ID on it, they can like hold the phone up and basically take the image of your face, as it were? That sort of belongs to them, you know, in some sense. They have an ability to take that from you. Likewise, your fingerprint, they can take your fingerprint from you, but they can't take the thing that's in your mind, which is the numbers.

• 1:11Michael Stevens?

  Exactly. That's what I thought was so exciting, that we are treating legally what's in your mind with more priority and privilege than your body. So if the cops arrest you and they tell you, "Hey, you gotta tell me your passcode," you do, they get into your phone with that passcode and they find text messages where you admit to this crime. This statement, I read it on the internet, was that they cannot actually charge you or bring that as evidence in court. However, if they found the texts because they just pointed your phone at your face and it unlocked, that's allowed. As it turns out, that is correct? Kind of.

• 1:53Hannah Fry?

  This episode is brought to you by Cancer Research UK.

• 1:56Michael Stevens?

  Here's something strange. Your DNA contains more ancient viral fragments than genes. The genes that build our cells make up only 2% of our DNA. And for years, that is what scientists focused on. They treated the rest, the ancient viruses and stuff, as junk.

• 2:16Hannah Fry?

  But now we know that that hidden majority, sometimes called the dark genome, influences how our biology works and how diseases like cancer behave.

• 2:27Michael Stevens?

  It's a reminder that progress rarely comes as a single breakthrough. It builds gradually. Cancer Research UK plays a central role in that progress, supporting decades of research into over 200 types of cancer, work that's helped double survival in the UK over the past 50 years.

• 2:46Hannah Fry?

  For more information about Cancer Research UK, their research breakthroughs and how you can support them, visit cancerresearchuk.org/the rest is science.

• 2:57Speaker 02

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• 4:47Speaker 03

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• 5:01Hannah Fry?

  Michael, how is it here? Are you trying to tell me here that something you read on the internet wasn't quite right? Well, that seems...

• 5:06Michael Stevens?

  It's really close. I looked into it, and as it turns out, we don't really know yet. Different courts in the United States have ruled differently on this. The Oregon Supreme Court tried a case where this woman, last name Pittman, had been pulled over and police found a whole lot of meth in her car. And they also found a whole lot of little baggies. And they were like, "She's selling meth. We just want to unlock your phone to see." And they used her fingerprint there at the scene to unlock the phone, and they were able to read messages showing that she was definitely selling drugs to people. In court, her lawyers said, "Hey, this violates her Fifth Amendment right to not have to incriminate herself."

• 5:50Hannah Fry?

  Because you should be able to say, "No comment. You know, I take the Fifth Amendment, whatever."

• 5:55Michael Stevens?

  That right to not incriminate yourself is famous because we see it in movies all the time. "Oh, I plead the Fifth." And we also have been living for hundreds of years under that kind of a law. What does that specifically mean? It means that the contents of your own mind cannot be used by a prosecution to convict you. Now, you can let them use it. If you want to get caught, you can totally tell them, "I did it," right? But you cannot be compelled to. If you refuse to answer their questions, you cannot be penalized. Other people, of course, can be. That's what a subpoena is. If you have information about something that I've done that's illegal, the court can compel you to witness against me.

• 6:39Hannah Fry?

  But it's not inside of your own head.

• 6:41Michael Stevens?

  And so today, when we have so much information about where we've been, what we've been saying, like actually documented on this little phone, and they're locked, not within our minds, but within our devices, it becomes really important for us to answer the question, is the contents of your phone the same as the contents of your mind? But we should talk about what exactly it means, so that we can figure out what we're talking about today. Prior to the year 1215, so we're going back a long time, how people were found guilty or innocent was a little bit more loosey-goosey. Okay? I'm sure you've heard of things like-

• 7:22Hannah Fry?

  Quite a lot was loosey-goosey.

• 7:23Michael Stevens?

  Yeah.

• 7:24Hannah Fry?

  In the 1100s.

• 7:25Michael Stevens?

  If you go back that far, hey, this is the 1200s, okay?

• 7:28Hannah Fry?

  Okay.

• 7:28Michael Stevens?

  But not everything was up to date in the world in the 1200s. Still isn't. But the point is that prior to then, in England, in Europe, there were trials by ordeal. You arrest someone, you think they're guilty of a crime, but they say they didn't do it. Easy. We don't need a jury, we don't need defined evidence. Let's just have them do something wild, like hold on to a red hot piece of metal. Or we could throw them into the ocean with rocks tied to them. And if they're truly innocent, surely God himself will intervene, miraculously save them, and we will all know that they're innocent.

• 8:10Hannah Fry?

  This is brilliantly flawless logic.

• 8:12Michael Stevens?

  It's brilliantly flawless.

• 8:14Hannah Fry?

  They use this quite a lot on the witch trials, didn't they? Although I seem to remember the witch trials, they did it kind of the other way around. If you managed to save yourself from the bottom of the ocean where you were tied down with rocks, then that demonstrated you're a witch. And if you did indeed die, then, oh, whoops, we just killed an innocent woman.

• 8:31Michael Stevens?

  Because if you were saved, it's because the devil saved you.

• 8:33Hannah Fry?

  Sure, sure.

• 8:34Michael Stevens?

  But in different circumstances, it's God saving you because you're innocent. So here's the thing. Lucy goosey is the key word. There were trials by fire, trials by water, trials by ingestion. If you're truly innocent, then we'll give you this poison and God will intervene. Now, believe it or not, that wasn't really popular.

• 8:54Hannah Fry?

  Okay, I am surprised.

• 8:56Michael Stevens?

  To be fair, though-

• 8:57Hannah Fry?

  With the criminals or the public at large?

• 8:58Michael Stevens?

  Well, with anyone. As I researched this, I found that actually a lot of modern scholars have said, to be honest, like, it wasn't that bad of an idea. Because if you look at the records of people who were subjected to trials of ordeal, there's like, a lot of people who were vindicated by it.

• 9:17Hannah Fry?

  Okay.

• 9:17Michael Stevens?

  Like, what really would happen is that someone who was guilty would just refuse to do it, and they would settle, and they would accept a punishment. If someone really said, "I will walk across the hot coals because surely God will save me," and everyone believed that he would, then an innocent person would decide to do it? And often, there was a lot of leeway over how terrible the ordeal was. And so it would kind of like, be orchestrated such that, all right, none of us believe they did it if they're willing to go through with it, so we won't make it too hard, and then we'll demonstrate to the public that they're innocent.

• 9:50Hannah Fry?

  Oh, nice, okay.

• 9:52Michael Stevens?

  So, another problem with early justice was coerced confessions. This was a much more common practice of like, well, if we torture the person enough, they'll eventually tell us that they did it. Or, they'll tell us the truth. As it turns out, no. Coerced confessions tend to be very unreliable.

• 10:10Hannah Fry?

  I mean, I would say that that's a, that remains a relatively modern problem there, Michael, I think. Coerced confessions. I think that one hasn't really gone away.

• 10:20Michael Stevens?

  Well, I know, the problem is, like, people still call confessed confessions, like, a war crime. They'll call it out, but whether or not it gets, you know, justice ever served, is a different question. These rights to not be compelled to-

• 10:36Michael Stevens?

  Incriminate yourself grew out of that historical context. A lot of the original people who came up with the importance of of not being forced or compelled to witness against yourself were also people motivated by freedom of expression, where they just didn't believe what they were supposed to believe according to the church or the or the political powers that be. And they thought, I shouldn't be compelled to admit my beliefs because I believe them strongly and I don't think that thoughts should be criminalized.

• 11:07Hannah Fry?

  Here's the thing, though, okay, because I think you could argue that in a lot of ways, if they take your blood or your hair samples or your saliva, you're sort of incriminating yourself there as well, though, right? Like, why didn't they come under the Fifth Amendment?

• 11:21Michael Stevens?

  That's the exception, yes. The Fifth Amendment has been interpreted as purely being the contents of your mind. So in that case of the state of Oregon versus Pittman, it was found that biometrics are an exemption from the Fifth Amendment. They really can force you to use your fingerprint to unlock your phone.

• 11:44Hannah Fry?

  So this comes down on the side of of of blood samples, hair samples, saliva samples.

• 11:48Michael Stevens?

  Exactly, and this was the motivation. The court said that if her phone had been locked with a passcode, they could not have asked her to provide that passcode. Because if she provides the passcode, she is conveying information that's in her mind that can indirectly cause them to learn all kinds of things about her. Whereas if you ask her to simply put her fingerprint on the phone, all you're really asking her to do is demonstrate that she can move her finger.

• 12:18Hannah Fry?

  Okay.

• 12:19Michael Stevens?

  Okay.

• 12:19Hannah Fry?

  The actual court said this?

• 12:20Michael Stevens?

  Yes.

• 12:21Hannah Fry?

  Wow.

• 12:22Michael Stevens?

  So biometrics are not a violation of your Fifth Amendment right, according to Oregon versus Pittman.

• 12:27Hannah Fry?

  Okay, everybody immediately go and change your phones, particularly if you happen to be in the mafia, you know, it's a good idea.

• 12:35Michael Stevens?

  Well, maybe. You see, there there have been court cases that found that biometrics unlocking with Face ID or a fingerprint is Considered testimonial.

• 12:46Hannah Fry?

  Mm hmm.

• 12:47Michael Stevens?

  That's a key word here. Testimony is when you divulge information that's in your mind.

• 12:52Hannah Fry?

  And that's opposed to physical evidence, which is parts of your body.

• 12:55Michael Stevens?

  That's right.

• 12:56Hannah Fry?

  Mm hmm.

• 12:56Michael Stevens?

  And so in US versus Brown, that case was in 2025, so just last year. They found that unlocking a person's phone with their fingerprint was actually a violation of their Fifth Amendment right. And this was actually a case that pertained to some people who were at the January 6th events at the US Capitol.

• 13:18Hannah Fry?

  Hmm.

• 13:18Michael Stevens?

  The plaintiffs in that case had their phones looked through and the court there ruled that it was inadmissible because they were compelled to give a fingerprint. And in that case, the court said they shouldn't have been forced to do that.

• 13:31Hannah Fry?

  Even the fingerprint was not okay.

• 13:32Michael Stevens?

  Even the fingerprint wasn't okay.

• 13:34Hannah Fry?

  Interesting. You're safe with a passcode. You may or may not be safe with a fingerprint.

• 13:38Michael Stevens?

  It's still definitely the case that a passcode is always upheld as, yeah, that's their information, which means the contents of your phone, when protected by a passcode, is treated like the contents of your own mind, where showing it is your choice. You have a right to be silent and your phone has a right to be silent, unless you lock it with your fingerprint or face ID, in which case.

• 14:05Hannah Fry?

  Game over, buddy. See you in 30 years.

• 14:08Michael Stevens?

  If you've committed some crimes, yeah.

• 14:11Hannah Fry?

  My mom, as I was growing up, would always tell me, don't ever put in writing anything that you wouldn't want your mother, your accountant, or your Catholic priest to see. And I think overall, actually, in life, that has been pretty good advice, but it does make me wonder what kind of shady shit that woman was up to.

• 14:29Michael Stevens?

  Yeah, this was like a rule of hers that she needed to teach you. Being on, being like a YouTuber, I feel like, don't write anything down that you wouldn't want to put on your YouTube channel, because it will always wind up being discovered, right?

• 14:44Hannah Fry?

  Okay, I see. Oh, sorry, I understand. Your YouTube channel is your version of my Catholic priest.

• 14:48Michael Stevens?

  Exactly, exactly.

• 14:50Hannah Fry?

  You know, Google searches, for a really, really long time, I was really careful not to put anything. Into a Google search that I wouldn't want my mother, my Catholic priest, my accountant to see. But actually, as time has gone on, I feel like I've relaxed that. You know, I think if you looked through my history of Google searches, you'd be like, what kind of weird stuff is this woman having having anxiety dreams about three o'clock in the morning?

• 15:12Michael Stevens?

  Oh, sure. For mine, people would be like, this guy can't spell anything. What the heck?

• 15:18Hannah Fry?

  But people have been done for that, you know, the Google searches, you know, how do you dissolve a body? How do I poison my wife? That kind of thing like people have that they those hold up in court, even though actually that sort of feels like a very private Google search in the middle of the night feels as close to what's going on inside your own head, inside your own thoughts as it's possible to be. You're not even really sharing it with anyone.

• 15:42Michael Stevens?

  Unlocking someone's phone to look at their search history is different than looking in their own mind because that search history is them reaching out into the world and performing an action. Whereas photos they've taken, I feel like that's a much more private action.

• 16:03Hannah Fry?

  Do you?

• 16:03Michael Stevens?

  Yeah, because if they've taken the photos and they haven't shared them, then it's kind of like an externalized prosthetic version of just looking at something and remembering it.

• 16:14Hannah Fry?

  Interesting. The one I'm I think is going to come up quite a lot in the future is whether chatbot logs. You know, if you're talking to chat GPT.

• 16:24Michael Stevens?

  I mean, I know they've already been used because the guy who's been fingered for starting the Palisades fire in California.

• 16:33Hannah Fry?

  Right.

• 16:33Michael Stevens?

  He was known to be in this in the area where it started. Right after or or soon after he started the fire, he was asking chat GPT like, hey, can I be found liable for a fire if I'm the one who threw the cigarette out? And the the authorities had access to that, and that was part of the case against him.

• 16:53Hannah Fry?

  And that was the thing that convicted him.

• 16:54Michael Stevens?

  Uh, that and many other things.

• 16:56Hannah Fry?

  Yeah, yeah, sure, sure.

• 16:58Michael Stevens?

  All right. So so far, we've been talking about whether or not authorities, the state, have the right to compel you to share information that's within your mind. And today, by extension, in your phone.

• 17:11Hannah Fry?

  I think the history of the law being in place makes a lot of sense. But it sort of feels like in the past, for something to leave your mind, there was a much bigger action that you had to take, you know? You sort of had to make much more effort for you to broadcast something out in the world. But once you reduce that barrier to entry of something leaving your mind, I mean, I'm thinking here about the neurotransmitters, that the, you know, the things that are being trialed on real humans at the moment, things like Neuralink, where you are essentially implanting computer chips into the brains of humans. I mean, what about in that situation? Is that leaving your brain?

• 17:48Michael Stevens?

  It is. But once it's out of your brain, we don't have laws that are clearly built for those scenarios. Who owns all that data from my brain that's now on a computer hard drive? Because in the past, the only way ideas would get out of my brain is that I said them, I wrote them down, and now it becomes witness testimony, and it's a thing that can be shared. But if a computer has a big log of my thoughts, well, then, do I own it? Or does the company own it? And how can it be used by that company? And these are still questions that we're trying to resolve. It's a big part of neuroethics. Like, what do we do now that we can look inside someone's brain? After the break, I want to look into something a little bit different,

• 18:31Michael Stevens?

  which is extracting information, not by compelling the person to share it, but by just looking directly into their own brain.

• 18:40Hannah Fry?

  Is that what you're doing now?

• 18:41Michael Stevens?

  That's what I'm doing right now.

• 18:43Hannah Fry?

  Are you looking into their brains?

• 18:45Michael Stevens?

  Oh, my gosh.

• 18:46Hannah Fry?

  Put that down.

• 18:47Michael Stevens?

  Put that. I can't believe you're thinking that right now. That's a good point. Yeah, you should go to the bathroom. Wow, I just was flooded with viewer thoughts as I did that.

• 19:02Hannah Fry?

  Something much.

• 19:02Michael Stevens?

  But should I be allowed to do that after the break?

• 19:11Michael Stevens?

  I live 7,636 kilometers away from Hannah, so we rarely get to see each other in person. That's what makes this such genuinely thrilling news for us. And maybe for you too. Because for the first time ever, you can see both of us live onstage at Goalhanger's inaugural festival. It's going to be amazing to be able to reach through the screen and meet those of you who watch and listen to the show in the flesh. The Rest Is Fest runs from the 4th to the 6th of September at London's South Bank Centre. So get some tickets and get ready for some fun. Some serious fun. Go to southbankcentre.co.uk to find out more.

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• 20:59Michael Stevens?

  I think one of the more pressing applications...

• 21:04Michael Stevens?

  And by pressing, I mean that this has been going on for decades, is what's known as the P300 signal. This is a signal in the brain. It's like an activation event of neurons that only happens when you recognize something.

• 21:17Hannah Fry?

  Mm-hmm.

• 21:18Michael Stevens?

  So if I showed you your children, it would light up. If I showed you a picture of my best friend from fifth grade, yours would not light up. I mean, it could. That'd be pretty cool.

• 21:28Hannah Fry?

  That would be pretty cool.

• 21:29Michael Stevens?

  But this, this was known to psychologists for a long time. And then the scientist, Dr. Lawrence Farwell, said, well, this could be used in court.

• 21:39Hannah Fry?

  Oh, oh, Lord.

• 21:41Michael Stevens?

  Right?

• 21:41Hannah Fry?

  Yeah.

• 21:42Michael Stevens?

  Like, now, hold on a second. This guy says he didn't do it. Well, let's show him photographs of the crime scene. And if his brain lights up, then he recognizes it.

• 21:52Hannah Fry?

  And that's physical evidence rather than testimonial? Or is it?

• 21:55Michael Stevens?

  That's the question. Is it testimonial? Testimonial means information from your mind.

• 22:00Hannah Fry?

  I mean, it's, it's information from your mind.

• 22:03Michael Stevens?

  It's information from your mind, but if we scan your brain for it, you aren't willingly giving it up. There's like three prongs to defining allowed testimony. It cannot be compelled. It must be information, and it must come from the mind. If someone volunteered to be part of a P300 test on their recognition, then it could be allowed because they've, they've consented to it. And that's how it's happened so far in courts.

• 22:32Hannah Fry?

  But you could just close your eyes and be like, I refuse to look.

• 22:34Michael Stevens?

  About 20 years ago, there was a guy named Terry Harrington, who had been convicted of a murder back in the 70s and had always, always denied that he was part of it. He always proclaimed his innocence. When this technology for the P300 event-related potential came around, he reached out and said, do it to me, because I wasn't even there. I'd never even been there before where the murder happened. And Lawrence Farwell went there and tested the guy's brain. And sure enough, all the locations and information that only the murderer would have known didn't cause any recognition signal in the guy's brain. Here's the problem, though. They didn't bring it to court because all they did is they confronted the witness who had fingered him.

• 23:17Michael Stevens?

  It was this guy Hughes who said, oh, yeah, Harrington did it. They came to the guy and they said, you know, we just did this brain scan and like, he passed. He wasn't there that night. And the guy went, oh. Um, well, I, can I recant? Because I actually lied.

• 23:33Hannah Fry?

  Wow.

• 23:34Michael Stevens?

  So the witness recanted 30 years later.

• 23:37Hannah Fry?

  Wow.

• 23:38Michael Stevens?

  And the guy was released.

• 23:40Hannah Fry?

  That's incredible.

• 23:41Michael Stevens?

  So it wasn't because of the P300 brain scan.

• 23:45Hannah Fry?

  Sure.

• 23:45Michael Stevens?

  But this was in Iowa, by the way. The Iowa courts said that they would consider that evidence admissible. However, it wasn't necessary for them to reverse his conviction.

• 23:55Hannah Fry?

  But then, in a lot of ways, this is going back to your trial by ordeal thing, right? Which is that the P300 test, if it's so good at detecting whether you recognize a piece of evidence, an individual, whatever it might be, only innocent people would ever want to go through that.

• 24:13Michael Stevens?

  Yeah, right? Surely the neuroscience machine will vindicate me. Now, ever since that Iowa case, a lot of other courts have said that P300 scans are inadmissible. But if the defendant really wants to do it, then that's their right.

• 24:30Hannah Fry?

  I see.

• 24:30Michael Stevens?

  They can divulge whatever, they can say whatever they want, but they cannot be compelled to say or be scanned in the brain against their will. But there isn't a constitutional amendment about this. It comes down to what different courts have decided in different contexts.

• 24:46Hannah Fry?

  Did you see the paper, 2023, I think it was, where admittedly with willing volunteers, there was a group of scientists who managed to reconstruct images that participants were looking at while they were in an fMRI scanner. I hope we'll be able to put a few of these pictures up on the screen. But it's phenomenal how close these images were. So people were given certain images to look at and just purely based on the readout from the fMRI. Having been trained on, you know, tens of thousands of images in the past, these algorithms were able to reconstruct what they were looking at with really, really incredible accuracy.

• 25:22Michael Stevens?

  I, I looked into this in a Minefield episode.

• 25:24Hannah Fry?

  Oh, yeah.

• 25:25Michael Stevens?

  And yeah, the, the idea is that, well, if I'm just looking at your brain activity, even really vaguely, even with like an EEG, MRI is better. But if I do this and I just show you a bunch of images and I know which ones you're looking at, over time, I can learn to associate certain activity. With certain colors and certain shapes and certain faces. And you do this 10,000 times. Yeah, you can start to show the person something and you don't even know what it is. But you look at the activity and a computer algorithm can go, I think they're looking at a question mark. Now, on Minefield, we looked even a step further, which is, well, we should be running this on someone's brain while they're dreaming. Because then we will be able to create on a computer screen what they are seeing in their dream.

• 26:07Hannah Fry?

  And did you?

• 26:08Michael Stevens?

  Maybe. Problem is, people don't really remember a whole lot about their dreams.

• 26:13Hannah Fry?

  Okay.

• 26:13Michael Stevens?

  So you wake them up and you go, were you dreaming about a tomato? And they're like, I don't, maybe, yeah, there was something red. And you're like, oh, maybe we did it.

• 26:20Hannah Fry?

  Okay.

• 26:21Michael Stevens?

  We certainly don't know that it looked exactly the way it did on the, on the computer.

• 26:26Hannah Fry?

  Oh, I like the idea of having a high res replay of my dreams.

• 26:30Michael Stevens?

  Wouldn't that be amazing?

• 26:31Hannah Fry?

  It would be cool.

• 26:32Michael Stevens?

  I think one of the problems is that dreams aren't necessarily a movie being played in your head. I think in a lot of ways, they're a collection of feelings and recollections and information being quite arbitrarily moved around and stored or not. And then when you wake up, I think you confabulate a lot of what that dream was.

• 26:52Hannah Fry?

  Stitch it together.

• 26:53Michael Stevens?

  You stitch it together and it makes sense. And then you remember it very differently than it was when it happened. So that's the biggest problem for this, like, recording people's dreams idea. But if we're able to figure out what you're dreaming about, or what you're looking at, or what you saw in the past. Well, then, should we be allowed to use that as evidence against you?

• 27:17Hannah Fry?

  But if the P300 thing is anything to go by, then the answer is no.

• 27:20Michael Stevens?

  Yeah.

• 27:21Hannah Fry?

  There is something special about your thoughts. There is something special about what's going on in your mind.

• 27:25Michael Stevens?

  That's right. It makes a lot of sense to me. I think we should protect people's thoughts. And by extension, today, I think that we should protect what's on their phones. Because it's basically just a prosthetic brain. And if your case requires breaking into someone's private mind or private phone, then you don't have a good enough case.

• 27:45Hannah Fry?

  But then, hold on, you said a Google search is you're putting something out there in the world. Don't you think putting something in a phone is putting something out there in the world?

• 27:53Michael Stevens?

  Okay, today I believe that, yeah, I think that eventually we're going to need to have a much clearer idea of just how private someone's phone is. Because while legally, it seems to be the case that pretty much all courts are agreeing that your passcode is protected and you don't have to give it. Your phone itself is not. So if the police take the phone and you refuse to give them your password, or your like symbol or whatever, they can still take it down to headquarters and hack into it.

• 28:22Hannah Fry?

  Hmm.

• 28:23Michael Stevens?

  And that's completely allowed. That's not a violation of your Fifth Amendment rights.

• 28:27Hannah Fry?

  Okay, sorry mafia bosses, we might have given you incorrect advice earlier.

• 28:31Michael Stevens?

  Yeah, right, I should have, I should have mentioned that.

• 28:33Hannah Fry?

  Yeah, now they're, they're coming for our families, so.

• 28:36Michael Stevens?

  That makes it feel a little complicated, because in that case, the P300, is it equivalent to compelling testimony against myself? Or is it the same as them just like looking around in my house with a warrant? Could they get a warrant for my brain?

• 28:53Hannah Fry?

  Because maybe there will be a point in the future where you can, and where you can sort of strap somebody to a gurney, make them, you know, stick on, stick them in an FMRI scanner, watch what's going on inside their brain, reconstruct everything that they're thinking and feeling, show them images of the victim, see how they react to it, and use that in order to, to really, truly determine somebody's guilt. But you know, maybe here's the thing about it, that sort of feels pretty uncomfortable to me.

• 29:21Michael Stevens?

  Yeah.

• 29:22Hannah Fry?

  In a lot of ways, but at the same time, I think we do need to ask ourselves, what is the point of a judicial system, right? Because all of these, these techniques that we have of like juries and reasonable doubt and the Fifth Amendment are all constructed because we're in a situation where you don't have access to the ground truth of somebody's guilt or innocence. You have no real way, no real, real way of accessing what actually happened. But if what you're, you know, describing here of like getting a warrant for somebody's brain, if suddenly there were a way to be absolutely sure, I mean, I'm slightly playing devil's advocate here, but, but maybe all of the other stuff is unnecessary.

• 30:01Michael Stevens?

  Yeah, and you know what, if we could... Accurately search people's brains and issue warrants for a search like that. A lot fewer innocent people would be punished or convicted. The problem then becomes, ugh, if they can look into my brain, they'll find that I didn't commit the crime that I'm charged with, but they might also find some embarrassing thoughts I've had or some other crimes I've been a part of. So I don't know how they would have to devise these brain searchers to like, you're only allowed to search memories from this time to this time. And you're only allowed to look at their memories involving this particular glove.

• 30:45Michael Stevens?

  You know, I think we can, we can concoct a technique in our minds that is satisfactory to us. But at the moment, it's very nascent. Like this technology is only so good.

• 30:57Hannah Fry?

  Absolutely.

• 30:58Michael Stevens?

  And that's predominantly why courts have been turning down P300 scans. Because it's just still too unknown how accurate it really is.

• 31:08Hannah Fry?

  I do also think on the other side of that same argument, right? I do actually think that a lot of our society works because of the assumption that not every time that a law is broken is that law enforced. You know, imagine if there was a system where automatically every single time you broke the speed limit, you would immediately get a fine, right? It becomes a real totalitarian state almost immediately. We live in a world where actually there is quite a lot of leeway. There is fuzziness around the edges. There is randomness, there is noise, and we're kind of a bit more comfortable with that.

• 31:43Michael Stevens?

  Yeah, but if we, yeah, as soon as we've got a really accurate way to

• 31:47Hannah Fry?

  Determine guilt.

• 31:47Michael Stevens?

  Determine guilt by scanning your brain, then it's going to become a hat that everyone has to wear. And as soon as you commit a crime, boom, we already know you did it.

• 31:57Hannah Fry?

  We know you did it.

• 31:58Michael Stevens?

  You would no longer have to have juries or judges. It would just be like, oh, yep, you were speeding or yep, you had an unclean thought. But, but at the moment, thoughts aren't crimes. There's one case where your thought is quite relevant to the court, of course. I mean, the most obvious one is intent, mens rea.

• 32:15Hannah Fry?

  Yeah.

• 32:16Michael Stevens?

  You can't just have done something wrong. You have to have known that you were doing something wrong and you have, you have a guilty mind. The other way is like, let's say fantasizing about committing a crime, not a crime.

• 32:29Michael Stevens?

  But it can be relevant to a court if I'm already in prison for the crime and I'm up for parole. And they're like, look, do you still fantasize about committing this crime? If I'm like, yeah, I do actually, then I probably won't get parole.

• 32:42Hannah Fry?

  Well, but is that not in part because the job of a parole board is at least in part to try and work out your chance of committing another crime if you're allowed?

• 32:51Michael Stevens?

  Exactly, exactly.

• 32:52Hannah Fry?

  And you fantasizing about doing something is a strong indicator, perhaps, that you may do it if when given the opportunity.

• 32:57Michael Stevens?

  That's right. But if I said that I fantasize about committing acts of vandalism every night, I'm not currently in prison for vandalizing anything, so it's okay that I do. And I do, by the way, I've mentioned this on the podcast, like, instead of counting sheep, I imagine how I would sneak in and vandalize the Hollywood sign. It's like, I did that hike a lot, and so I know like where the cameras are, and I know where the paths are, and I keep thinking, oh, and I know what color to wear based on like the color of the grass. So basically, I'm planning out this whole vandalizing crime every night, but that's not bad, and it doesn't, it doesn't hurt my life, doesn't get me in trouble. But if I already was in prison for vandalizing the Hollywood sign, and I kept admitting that I was fantasizing at night about it.

• 33:39Hannah Fry?

  Then it's a problem.

• 33:40Michael Stevens?

  I'd probably have to keep serving my time in prison.

• 33:42Hannah Fry?

  What's, what's good here is that we've, we've learned that that's a thought, that you were happy to be within a YouTube video because you just said it on a YouTube video.

• 33:50Michael Stevens?

  Yeah, right. Then when it comes to knowledge, another thing that I was really interested in was, is there anything that it's just illegal to know? I mean, interestingly, there are things that you can be convicted of that you didn't know. But if you don't ask because you kind of suspect, then you've committed a crime, even though you don't know for sure.

• 34:14Hannah Fry?

  Yeah.

• 34:15Michael Stevens?

  So now we're going to talk about an emerging huge question in neuroethics, which is, mm, okay, I can, I'm a police officer, I can search someone's home if I get a warrant from a judge. What about a warrant for someone's brain? That would certainly help us solve a lot of crimes, right?

• 34:33Hannah Fry?

  Yeah.

• 34:34Michael Stevens?

  If I could go, look, I can't compel you to say your password, but I can take this little scanner out and go and find your password. For example, I was reading about a school, like an elementary school in China, where the children wear these headbands that vaguely measure brain activity. It's definitely not recording exactly what they're thinking, but it can give us information about how focused they are. And I think these began as a biofeedback kind of thing where the kids can become more focused. They can get feedback on how focused their thoughts are and it's very meditative. But then you can also start using it to catch the kids that aren't focused during class.

• 35:13Michael Stevens?

  And it doesn't take much to imagine a world where we can collect more specific data from their brains and go, hey, you were thinking about cheating on this test and so therefore I'm going to treat you differently. And what do we do about that? We're not there yet. The technology hasn't yet forced us to bring this in front of a judge or a court. But I think we'll be there pretty soon.

• 35:33Hannah Fry?

  I think we'll be there pretty soon. There's a company who I went to go and meet in Brooklyn where they are creating a set of headphones that around the padding of the of the earpiece is essentially this the same technology, which is measuring the the brainwaves as you know, as you can through the skull. And the idea was using a very similar technology to your Chinese school example. They can tell essentially how concentrated you are. And the kind of the the main hope for this is that it's a little bit like a Fitbit but for your brain. So you want to concentrate more. It says you've concentrated for this many hours a day. It's like for your own information, your own personal information. And I tried it and it was pretty good, actually. And it was good that it that this there was this learning element to the algorithm, right?

• 36:17Hannah Fry?

  So it would tell that you could feed in your other data, like how well you'd slept and stuff. And you know, how much hydration you'd had and what kind of music made you made you concentrate more. It's sort of, I I can see where that's going. But I also think that while this technology might have a really beneficial side that people and consumers want to get, as soon as that data is out there.

• 36:39Michael Stevens?

  Yeah.

• 36:39Hannah Fry?

  Right? It's like there's a very dodgy, the Chinese school thing could easily happen within a corporate environment where they want to ensure that people are are focusing and if they're not focusing, they get fired. There's a is a very dark slippery slope even before you get to let's reconstruct people's thoughts.

• 36:56Michael Stevens?

  Oh, I know. Yeah, imagine that your boss knocks on your door. Hey, Michael, so I'm looking at your brain scans and you were having a lot of fun for two hours today. You shouldn't be having that much fun at work. And then they cut your hours or something.

• 37:09Hannah Fry?

  Yeah, right.

• 37:10Michael Stevens?

  It doesn't take very much of a leap either to think about what you enjoy doing with the feedback and oh, what's relaxing me. Then suddenly, the Coca-Cola company says, we'd like that data. We'd like to be able to say to Hannah, hey, when you're hydrated, you're feeling good. So maybe you should buy a Coke because we're noticing that you're a little bit like less, less relaxed in your brain right now. And we can get like super targeted ads. Hey, Michael, you're feeling kind of frustrated by that thing that happened at work today. Some chocolate would help, you know?

• 37:44Hannah Fry?

  Yeah. It's like the TikTok algorithm, but plus, plus, plus, plus, plus.

• 37:48Michael Stevens?

  Yes, the TikTok algorithm, but instead of just knowing how long I've had a reel open or what buttons I've tapped, it actually looks at how my brain is reacting. And then things get pretty scary because I could even be told by a government, by an advertiser, I know you don't think you like this, but our analysis of your brain shows that you do enjoy it. So we're going to give you more of this. And I'm like, I don't want this. And they're like, you do though, at a subconscious level, so here you go.

• 38:16Hannah Fry?

  Hmm. Yeah, that's quite dark, isn't it? But it's also going back to the thing that you were talking about right at the beginning. You know, if you are buying products, you're sort of voluntarily collecting this data for yourself. I mean, I wear one of the rings, right? That like collects this kind of bio data for myself. I've worn the Whoop and various other things in the past. If you're kind of creating that data for yourself, buying the headphones, whatever, you're not being compelled to construct it.

• 38:40Michael Stevens?

  It was your choice to construct it, but I think that choice is probably made with the expectation of some kind of privacy. In fact, in that case, US versus Payne, they specifically ruled that biometrics to unlock a phone, like I think in that case it was a thumbprint, is not testimonial, especially because the parolee in that case had a diminished expectation of privacy. So a lot comes down to what the person expects. I think we also are going to find ourselves hitting a wall, which is, does the brain tell the truth? A scan might say that I recognize something. But do I consciously recognize it? Here's where this is coming from.

• 39:24Michael Stevens?

  I just read Patricia Churchill's Conscience. It's a book about the evolution of the human conscience. Like, I feel guilt and shame all the time, but as far as we know, armadillos don't really seem to have as much of a concern for obeying their conscience.

• 39:41Hannah Fry?

  I mean, an embarrassed armadillo is quite a good image.

• 39:43Michael Stevens?

  An embarrassed armadillo, I'm sure, could happen. Like, I'm not going to take that dignity away from them. But where did, where did, how did this come about? Like, we certainly know that rocks don't appear to have moral codes and feelings of guilt. Anyway, I highly recommend the book. But one thing she talked about was that brain scans that try to look for disgust reactions to things like images that are shocking or, or revolting. Your brain's reaction does not seem to correlate with people's reaction on surveys. So you can show a person a photograph of like a guy with a mouthful of worms, and they'll be either like, oh, oh, I hated that. And some are like, nah, it's, I mean, it's, I wouldn't do it, but I'm not, I'm not feeling like

• 40:29Hannah Fry?

  Horrified by it.

• 40:29Michael Stevens?

  Horrified or uncomfortable. But then their brains will show something different and will be like, I don't know, you, you were spiking in your amygdala and your fear center. And the person's like, I don't know what to tell you. And so it could be that there's multiple layers in the brain. And which one we spy on really matters because my brain might react with horror to something, but that doesn't become the salient feature in my awareness.

• 40:55Hannah Fry?

  You remember, a few weeks ago, we had a field notes where someone was asking about consciousness and we, and we were talking about whether there even is this single little humunculus inside of you, whether there really, really is like a single entity that is you, or whether actually the sort of consciousness that you feel is just an illusion of these different processes that are pulling in all sorts of different directions. I do kind of wonder, as we get further and further down this road, whether actually this idea is going to splinter apart quite a bit and that maybe there is way more and simultaneously less to us than we ever thought imaginable.

• 41:26Michael Stevens?

  Exactly. Yeah. I don't want to be held responsible because my brain involuntarily recognized a crime scene that I don't remember being at. I can't control how it reacts to things. At least, I feel like I can't. So, yeah, boy, future lawyers and legal scholars out there, you've got your work cut out for you.

• 41:48Hannah Fry?

  I'll tell you one thing that would be quite good, though, if you can properly read people's minds. I think we realize just how weird all humans are. I think the real weirdness of people, I think people are still quite quiet and quite private about how actually weird they are.

• 42:02Michael Stevens?

  Yes. And, once we are able to collect lots and lots of data from your brain about what you're thinking and feeling, it's not going to clarify anything about ourselves. If anything, it's going to make us go, oh, maybe I don't love that person like I thought I did. There's going to be so much information that it's going to make everything more difficult, including human privacy rights, so.

• 42:28Hannah Fry?

  I think, actually, we go back to the halcyon days of the Lucy Goosey 1200s.

• 42:32Michael Stevens?

  Yeah, we'll go back there. I mean, it's weird. There's a whole body of work around people admitting that, like, you know what? The trial by ordeal was kind of like very well-suited for small communities. There was almost like an unspoken idea of whether the person was guilty or not, but no one wanted to be the one to proclaim that person's innocence or guilt. So they would intentionally, like, subconsciously rig up an ordeal that the person could pass or not, depending on what the community sentiment was. And then when the person miraculously survived their ordeal that actually wasn't that hard to survive, they all went, phew, God solved it. We didn't have to. None of us had to come

• 43:17Michael Stevens?

  forward and be the one that proclaimed the sentence.

• 43:21Hannah Fry?

  Let's go back to those days, I think.

• 43:23Michael Stevens?

  As long as we're in small enough groups.

• 43:24Hannah Fry?

  Okay, do.

• 43:25Michael Stevens?

  But in really big societies, you develop this, perhaps, you develop a need for an authority that can say... Guilty or not, and that's how it's going to be done.

• 43:36Hannah Fry?

  We just feel a little bit more comfortable about it when it's got a bit of fuzziness.

• 43:39Michael Stevens?

  Yeah, yeah, yeah, yeah. So I hope your brain is doing well out there. I do recommend using a passcode to lock up your phone.

• 43:47Hannah Fry?

  Yeah, I'm going to be changing mine immediately.

• 43:49Michael Stevens?

  If you do, if you switch to a passcode, just email us the passcode at [email protected].

• 43:57Hannah Fry?

  We will file it into our brains and promise never to speak of it on YouTube to our Catholic priests or mothers.

• 44:05Michael Stevens?

  Yeah, the email account, [email protected] is protected by a password, so you'll still be safe from the police.

• 44:13Hannah Fry?

  You'll still be safe. See you next time.

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