Science You Believe That Isn't True & The Story of The Lie Detector - SYSK Choice

Speaker 1 Today on something you should know, how is it that trees fight crime?

Speaker 1 Then science myths that many people believe, like sugar makes kids hyper, water is a good conductor of electricity, and lightning never strikes the same place twice.

Speaker 2 The classic is the Empire State Building. It's typically struck, I think, about 25 times a year.
In fact, there's even one guy, there was a U.S.

Speaker 2 park ranger called Roy Sullivan, who's been struck by lightning seven times in his career thankfully survivable

Speaker 3 also are men better drivers than women and the polygraph or lie detector where did it come from how does it work and does it work essentially the reason the polygraph has been so successful is because of the theater around it right it works because people believe it works so that the mere threat of being attached to a polygraph can compel someone to confess to the crime before the exam even takes place all this today on something you should know

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Speaker 1 Something you should know, fascinating intel, the world's top experts, and practical advice you can use in your life.

Speaker 2 Today, Something You Should Know with Mike Carruthers.

Speaker 1 Hi, welcome and thank you for joining me for another episode of Something You Should Know. And we're going to start today talking about trees.

Speaker 1 If you live in a neighborhood that has a lot of nice big trees, it's a little safer than neighborhoods without them. According to the U.S.

Speaker 1 Forest Service, less crime occurs in neighborhoods with big trees in the front yards and along the street. So what exactly makes having trees a deterrent to crime?

Speaker 1 Well, for the most part, it's an unexplained phenomenon, but researchers have come up with a few ideas.

Speaker 1 Some say trees signal that the area is well cared for, similar to the broken windows theory, which suggests that disorder invites crime.

Speaker 1 Some say green spaces make an area inviting and can lead to more informal surveillance.

Speaker 1 Other theories point to the well-documented calming effect of vegetation and nature, or that the idea that greenery promotes trust in the community.

Speaker 1 Whatever the reason, trees fight crime, and that is something you should know.

Speaker 1 I'm sure you've heard statements, scientific-y kind of statements like lightning never strikes the same place twice, or your blood is red because of the iron in it, or that the Big Bang theory explains the beginning of the universe.

Speaker 1 But these are actually examples of statements that are not true.

Speaker 1 And there are a lot of them. Things that you may believe that just aren't so.
And here to reveal several of them and explain why they're not true is Brian Clegg.

Speaker 1 Brian is a science writer and speaker who has written over 40 science books. One of them is called Lightning Often Strikes Twice: The 50 Biggest Misconceptions in Science.
Hi, Brian.

Speaker 1 Welcome to Something You Should Know.

Speaker 2 Thanks for having me.

Speaker 1 So, what made you decide to tackle this, to try to explain that a a lot of things that we perhaps believe about science are in fact not true?

Speaker 2 I spend a lot of time talking to people about science,

Speaker 2 and all too often what comes up is it's a bit more complicated than we thought, that science tends to be a little more complicated than we think about it.

Speaker 2 And what I'm looking at here in a fairly light way, a fairly fun way, is

Speaker 2 areas where we think that science is different from the way it really is, or where we simplify it so so much that actually we don't really understand what's happening.

Speaker 2 So it's just trying to open up a little bit. It might be urban myths, it might be

Speaker 2 folklore, or it might just be not quite getting the science right in what I hope is an enjoyable way.

Speaker 1 Well, let's get specific. And one that you talk about that I have always believed is that water is a very good conductor of electricity.

Speaker 1 And, you know, you see in the movies, somebody throws a toaster that's plugged in into a bathtub to kill somebody or you know to me i've always thought water was a very good conductor of electricity

Speaker 2 and it seems crazy to say water doesn't conduct electricity but actually it's a really bad conductor of electricity but what is happening is it's the impurities in the water that enable it to do that conducting.

Speaker 2 So if you take totally pure water,

Speaker 2 it's a really bad conductor. And sometimes there's little things like that, or for that matter, toast.

Speaker 2 Toast Toast falling butterside down. You know this thing, you drop a slice of toast, it falls on the floor.
It's always the butterside that hits the floor. Or is it? Can that really be true?

Speaker 2 And a number of TV shows have actually tried to demonstrate it's not true. But unfortunately, what they've tended to do is toss toast in the air, a bit like tossing a coin.

Speaker 2 But the reality is, when you drop a slice of toast, you don't throw it up in the air like a coin. It slides off your plate or it slides off the work surface.

Speaker 2 And they're just about the right height that when something slides off and starts to turn, it has enough time to turn half a turn. So the butterside's gone down, but not enough time to go all the way.

Speaker 2 So it genuinely is true that even though lots of people think, surely it can't really be true that toast always falls butterside down. It pretty much always does.

Speaker 1 Well, let's go back to the water one because, you know, you're told not to stand in water when you're holding something electric because the water will, that there's something about standing in water that's going to kill you.

Speaker 1 So something's got to be there other than just the impurities. No?

Speaker 2 No, absolutely not. The actual water, literally pure water, H2O, is a bad conductor.
It's a good insulator.

Speaker 2 But the fact is, almost all the water we deal with on a day-to-day basis, the water that comes out

Speaker 2 faucets in the bathroom, is water that has minerals in it. And that's a good thing, you know, on the whole.
There's nothing wrong with that. It's not a problem.

Speaker 2 But these minerals are in the form of what are called ions. So they're basically positively or electrically charged, negatively electrically charged.

Speaker 2 And that means that they can carry an electrical current. And it's those impurities in the water that actually carry the current.
And it is dangerous, of course.

Speaker 2 Yes, you don't want to play around with electrics when you're in contact with water because, on the whole, the water we experience isn't pure.

Speaker 1 So since it's the title of your book, does lightning strike twice?

Speaker 2 Yep, it certainly does. I think one of the reasons for this is, you know, lightning is probably the most dramatic natural occurrence that most people have experienced.

Speaker 2 You know, there are bigger things out there, more horrific things like earthquakes and so forth. But the fact is, most people have experienced lightning.

Speaker 2 It's pretty frightening stuff if it's fairly close. And if you ever see an actual lightning strike where it hits a tree or something like that, it's very dramatic.

Speaker 2 And certainly, you know, over the centuries, most people would not have seen seen lightning striking the same place twice. And because of that, a kind of folklore built up around it.

Speaker 2 But the fact is, it does happen and it happens a lot. You know, any one time around the world, there are maybe 20,000 lightning storms, thunderstorms happening.

Speaker 2 And somewhere where there's a nice big, pointy thing, you will get more than one strike. So the classic is the Empire State Building.
It's typically struck, I think, about 25 times a year.

Speaker 2 And it has been struck as many as 15 times just in a single storm. The fact is, lightning really does strike more than once on the same location, but this kind of it's almost become a

Speaker 2 way of referring to something. So, we don't necessarily literally mean lightning doesn't strike twice, but rather more metaphorically, it's not likely to happen.

Speaker 2 In fact, there's even one guy,

Speaker 2 there was a US park ranger called Roy Sullivan, who's been struck by lightning seven times in his career, thankfully survived them all. Wow.

Speaker 1 He's either really lucky or really unlucky. I mean,

Speaker 1 just in terms of the odds, that seems like

Speaker 1 he must have to be trying to be struck by lightning because nobody can, that just seems impossible.

Speaker 2 I'm not sure he's still with us, but when he was around,

Speaker 2 I'm not surprised.

Speaker 2 The kind of job he was doing, he was out there out in the wilds a lot, out in places where you may possibly get struck by lightning more than most of us are.

Speaker 1 One of the fun ones,

Speaker 1 because I've always wondered how you would ever know this, is that a goldfish has a three-second memory. How would you ever test that in the first place?

Speaker 2 Anybody who actually owns fish, particularly if you have a pond, knows instinctively almost that this isn't right. Because the fact is,

Speaker 2 goldfish learn, for instance, that if you come to the edge of a pond in a particular place, holding something and sort of shaking it around, food's coming, and they come to you. They remember it.

Speaker 2 They do have a memory.

Speaker 2 But in

Speaker 2 scientific terms, it's been tested by training them, for instance, to go through mazes and they remember how to do that.

Speaker 2 In fact, all the evidence is that the original three-second memory bit came from a commercial, an advertisement that was done.

Speaker 2 just humorously referring to this and somehow it's become part of what we tend to believe. And it's handy for a joke,

Speaker 2 but it's not really something.

Speaker 1 Of all the things you talk about, if any one of them has crept into conventional wisdom more than any other, is the idea that sugar makes kids hyper.

Speaker 1 I mean, so many people believe that because it's their experience, that they see it. Kids have sugar and they seem to get hyper.
So how can that not be true?

Speaker 2 It's a problem that you get get in a lot of scientific experiments, actually, not just the anecdotes, because if somebody is just reporting, say, how they feel or what's happened, we can't actually isolate what the cause is.

Speaker 2 Now, what you actually find in practice is that when people have said, oh, yeah, the kids have got really excited, they've had lots of sugar. there is often some other thing going on at the same time.

Speaker 2 So, you know, take children to a party. Yeah, they get lots of sugar, they get really excited, but also they're at a party.
So, is it really surprising that they're getting excited?

Speaker 2 That just is no good scientific evidence.

Speaker 2 You know, when you treat it scientifically, which means you have to separate off all the different influences, put people in a controlled situation so that you can actually separate it off what is causing something.

Speaker 2 There is no good evidence that consumption of sugar actually makes them hyper.

Speaker 1 You claim that the Big Bang theory does not explain the beginning of the universe, but I thought that's exactly what it did explain. So sort that out for me.

Speaker 2 That's quite a nice little example of the,

Speaker 2 it's a bit more complicated than that. The Big Bang theory is a theory of how the universe grew from practically nothing all the way up to what we have today.

Speaker 2 And we think that has taken about 13.8 billion years for it to go from a very tiny,

Speaker 2 practically nothing, up to what we have now. And the Big Bang Theory is very successful at explaining that, but we tend to kind of associate it with literally the beginning of everything.

Speaker 2 And that's the one thing the Big Bang Theory doesn't do for us. It doesn't actually explain why or how the universe came into being initially.

Speaker 2 that very first start it has to already have if you like the laws of physics have to be there already it doesn't explain where they come from and the actual initial start of the whole thing requires if you like it to be there already for it to then start expanding so it's not quite made it and the other thing about it is we have a problem just seeing back that far now the universe is really quite generous to us because light takes a long time to get to us from very distant places so the further out you look in the universe the further back you see in time and we can see back until maybe

Speaker 2 300,000, 400,000 years after the beginning. But beyond that, we can't see because the universe wasn't transparent before then.
Light couldn't get through it.

Speaker 2 So, what that does mean is that those first years, we struggle a little bit to be sure exactly what happened then. And certainly, the Big Bang doesn't give us any insights of the initial beginning.

Speaker 2 So, it's just a slight tweak, if you like. It's a great theory.
It explains a lot. It gives us a time scale for the universe.
But what it doesn't do is say how the universe came into being.

Speaker 1 We're talking about science myths, things that a lot of people believe that just don't happen to be true. My guest is Brian Clegg.

Speaker 1 He is author of the book, Lightning Often Strikes Twice, the 50 Biggest Misconceptions in Science.

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Speaker 1 So Brian, what about blood? People say that the reason your blood is red is because it has iron in it and iron makes it give it that red color, but you say that's not true.

Speaker 2 Blood is red because of hemoglobin. So this

Speaker 2 substance in the stuff that carries the oxygen around the body. And that hemoglobin does contain iron.

Speaker 2 And so it's quite easy to get a little bit confused and think, okay, well, iron usually makes things reddish, you know, so rust is iron oxide,

Speaker 2 it's an iron compound. Mars looks red because there's a lot of iron in the surface.
So we tend to associate iron and redness.

Speaker 2 But as it happens, the reason hemoglobin is red is actually actually due to the shape of the molecule, the way it interacts with light. It's nothing to do with the fact the iron's in there.

Speaker 2 So that's one aspect of it. It's not actually caused by the iron.
And the other thing is the blue blood thing

Speaker 2 is not about the colour of the blood itself. It's about the way that light interacts with your veins.
It's quite separate. from the colour of the blood in them.

Speaker 2 Colour is quite interesting, you know, sometimes it's caused by a pigment, so sometimes it's caused by the colour of stuff, but sometimes it's structural.

Speaker 2 So actually the shape of something can change the appearance or the way light interacts with molecules. You know, if you look up at the sky, the sky is blue, but there's no blue pigment in the sky.

Speaker 2 There's nothing up there that is blue. It's literally the way the light is interacting.
with the molecules of air.

Speaker 2 And similarly, when you see the blue veins in your arm, it's not that the blood in them is blue. It's the way the light interacts with the material that makes up the veins.

Speaker 1 Something I've heard, and I think a lot of people have heard this in one form or another, that

Speaker 1 you can't explain how a bee flies, that a bee flies in defiance of the laws of physics. It's just impossible to explain.
It's a mystery. And you say it's not a mystery.

Speaker 2 The reality is that bumblebees don't fly the way you might think. So, you know, you think of of a bird flapping its wings, it's fairly obvious what's happening.

Speaker 2 It's flapping its wings up and down, that pushes the air down, effectively pushes the air, the bird up as it pushes the air down. Bumblebees' wings move in a much more complicated way.

Speaker 2 They basically almost act a bit like a helicopter in that they have a kind of curved motion. And the result of that is they actually generate more lift.
than you would expect from those little wings.

Speaker 2 The other thing about bumblebees actually is they look chunky, you know, compared compared with an ordinary insect. They look pretty fat, but actually it's still very light.

Speaker 2 So it isn't as dramatic looking,

Speaker 2 as dramatic as it actually looks to be. And the fact is, there's no problem at all with bumblebee wings supporting bumblebees.
In some ways, a more interesting example is kangaroos.

Speaker 2 because it is generally genuinely true that kangaroos use more energy or appear to use more energy when they bounce along than they consume.

Speaker 2 They seem to be able to actually give out more energy in their bounces than they've consumed in their food.

Speaker 2 And the reason for that is it's a bit like the way a rubber ball works. You know, if you drop a rubber ball on the floor, it bounces.

Speaker 2 When I was young, they had these things called super balls, super balls that bounced really high. I don't know if you ever had one of those.

Speaker 2 And kangaroos are a bit like that.

Speaker 2 So when they hit the ground it's not a case of all the energy they're putting into their muscles is wasted it's actually more like storing up energy in a rubber band as they hit the ground and then it bounces off and they use up that extra energy they've stored away so they can do what seem to be amazing things

Speaker 2 um even though

Speaker 2 In practice, they're not breaking the laws of physics.

Speaker 1 You say that it's a false statement to make that nothing can travel faster than the speed of light. But I've always heard that the speed of light is the absolute limit anything can travel.

Speaker 1 So I'd like to hear that explanation.

Speaker 2 It's another of those little, it's a little bit more complicated. We're oversimplifying when we say the speed of light is the limit.
The real thing is the speed of light in a vacuum is the limit.

Speaker 2 So the fastest anything can go is the speed that light goes through empty space.

Speaker 2 But light can also go through other stuff. It can go through water, it can go through glass, and when it does, it slows down.

Speaker 2 So light goes considerably slower through water or through glass or another solid transparent substance.

Speaker 2 And when it does that, it slows down sufficiently that physical objects can move faster than the speed the light's going.

Speaker 2 And there's something called Cherenkov radiation that happens in nuclear reactors.

Speaker 2 If you've ever seen a video of one of the old nuclear reactors that had water surrounding the nuclear pile, it glows blue.

Speaker 2 And the reason it's glowing blue is that little particles that are coming off out of

Speaker 2 the nuclear reactor are actually going faster through the water than the speed of light. through the water.

Speaker 2 And that produces a kind of optical equivalent of a sonic boom, which produces this blue glow. So, yes, it's true.
The speed of light in a vacuum is the absolute limit.

Speaker 2 But if we just say the speed of light is as fast as you can go, it's not true if you're not in a vacuum.

Speaker 1 I remember this one, that supposedly there were subliminal messages in movies, like just a still frame of a drink or a snack or something that didn't register consciously with you, but would make you want to go to the lobby and buy a drink or some popcorn or something and i remember people talked about that

Speaker 2 and the fascinating thing about this one is it was if you like a deliberate urban myth so a guy who was in uh advertising and marketing produced a fake paper effectively saying that this was the case and he used this to try to sell the idea that these subliminal messages would make people want to drink more of a particular beverage or want to go out and have a hot dog or whatever.

Speaker 2 And the fact is, it just wasn't true. There is no good evidence that these subliminal messages work.

Speaker 2 But the fact is, you know, so many people have heard this that we still today, in a number of countries, for instance, it's illegal to use subliminal messaging.

Speaker 2 Interestingly, there are very subtle effects that do seem to happen as a result of it, but what certainly isn't true is that it'll suddenly turn people, you know, into the urge to drink a particular drink or eat a particular substance well but there's two questions here there there's does it work

Speaker 1 which apparently doesn't work very well but but also did it happen did did were people putting frames that you could not consciously see in the movie to try to make it work

Speaker 2 certainly in the original no So it was totally fictional. It was made up the original that was written up.
It never did happen then. Since then, people have tried it,

Speaker 2 either tried it as experiment to see whether or not it works, but also some people have tried to influence others by putting frames in this way.

Speaker 2 But I say all the scientific evidence is that it has very little impact.

Speaker 1 Well, it's fun to trace back the origins of some of these misconceptions. And you also wonder why they persist so much.

Speaker 1 I mean, some of these things have become so ingrained in the kind of collective consciousness, we just accept them on face value, but clearly they're not true.

Speaker 1 I've been talking with Brian Brian Clegg, and the name of his book is Lightning Often Strikes Twice: The 50 Biggest Misconceptions in Science.

Speaker 1 And if you want to read it, there's a link to that book at Amazon in the show notes. Thanks, Brian.
Great to have you on.

Speaker 2 Okay, great. Thanks very much.

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Speaker 1 It sure would be great if there was a way to tell if people were lying. In fact, we've talked on this podcast about how to spot a liar by observing people and looking at their behavior.

Speaker 1 But the fact is, you can never really tell 100%.

Speaker 1 Some people are just good liars. If only there was a machine.

Speaker 1 Well, there sorta is. It's called a polygraph, sometimes called a lie detector.
You see it in movies and TV shows, and it's supposed to tell if someone is being deceptive.

Speaker 1 So how does a lie detector or polygraph work? And does it work? After all, the results of a polygraph test are not admissible in most courts. So it makes you wonder, how accurate it can it be?

Speaker 1 Well, here to tell the fascinating story of the polygraph is Amit Katwala.

Speaker 1 He's an award-winning journalist, a senior writer at Wired, and author of the book, Tremors in the Blood, Murder, Obsession, and the Birth of the Lie Detector.

Speaker 2 Welcome, Ahmed.

Speaker 3 Thanks for having me, Mike.

Speaker 1 So what is the basic theory of how a polygraph is supposed to work?

Speaker 1 My understanding is that supposedly when you lie, because you're lying, there are physical changes, like your heart rate increases and your blood pressure goes up.

Speaker 1 Things happen because you know you're lying and that that machine registers those changes and aha,

Speaker 1 you're a liar.

Speaker 3 That's the principle or the theory, and we'll get into why that maybe isn't necessarily true later on, I'm sure.

Speaker 3 But yes, the theory is that if you are doing a polygraph exam, you are going to be scared about getting caught.

Speaker 3 So, when you get asked a question that you know you're going to have to lie on, your pulse will start going up, your blood pressure will go up, you might start breathing differently.

Speaker 3 And a skilled polygraph examiner, so the theory goes, should be able to tell the difference between someone who's lying and someone who's telling the truth based on how those things change when they're asked the question.

Speaker 1 And so,

Speaker 1 I've always wondered:

Speaker 1 if you know that, why would you ever agree to be tested?

Speaker 3 It depends on the scenario, I think. A lot of government jobs in the U.S.
still require a polygraph exam. So certain military roles, certain police roles.
So some people don't have a choice.

Speaker 3 That was much more rampant until the late kind of 80s when it was outlawed in commercial enterprises.

Speaker 3 But there was a brief period when even companies like McDonald's were doing polygraph tests on their potential employees. For criminal cases, you know, I think

Speaker 3 sometimes it's presented as a waste for people to clear their name.

Speaker 3 So I can see why if you are innocent, you might be tempted by that. And maybe if you're guilty, you sort of think, well, you know, I can maybe get away with it.

Speaker 1 It seems such a murky thing because everybody who knows about polygraphs knows that, or at least the legend is, that

Speaker 1 the results are not admissible in court. So how accurate could they possibly be if a court is looking for the truth and refuses to use it?

Speaker 3 Exactly. That's a really big kind of flaw in the polygraph.

Speaker 3 And actually, the polygraph was one of the devices that established the set of standards that we now use to determine whether something is admissible in court or not.

Speaker 3 It was one of the real test cases where they actually looked at it and they thought, hang on, maybe this isn't really science.

Speaker 1 So where did it start? What was, I mean, it sure would be great. to have something you could, you know, make somebody stick their finger in and go, oh, he's lying

Speaker 1 and be sure that you're right. So where did this all begin?

Speaker 2 Who thought, hey, I got an idea?

Speaker 3 The polygraph machine specifically, which is, I guess, what most people think of now when they think of a lie detector, has its origins in Berkeley, California in the 1920s

Speaker 3 with the Berkeley Police Department and a police officer called John Larson. John Larson was a physiologist by training.
He wanted to become a criminologist, which is a very new field at that time.

Speaker 3 And he took a job in Berkeley because Berkeley was, the Berkeley Police Department was led by a kind of visionary police chief called August Vollmer.

Speaker 3 Vollmer was one of the first police chiefs in America to try and bring science or evidence to policing.

Speaker 3 So he gave his officers bikes because he kind of thought that that would enable them to cover more ground. He gave them radios, he started doing crime mapping and all this kind of pioneering stuff.

Speaker 3 And as part of that, he also started to hire college graduates as police officers, which was a real revolutionary step at the time in the kind of 1910s, 1920s.

Speaker 3 So John Larson was one of these college cops, and

Speaker 2 he

Speaker 3 and Vollmer came across this paper by a guy called William Marston.

Speaker 3 He was a psychologist at Harvard University, and he noticed that when he asked his peers to tell untrue stories, their blood pressure went up.

Speaker 3 So, Larson thought, well, okay, that's an interesting insight, but how can I systematize that?

Speaker 3 How can I turn that into something objective that can be measured and where the measurements can be recorded so that they can be referred back to later?

Speaker 3 And it's that insight, you know, how can you take this thing that we think we've identified where blood pressure goes up when people lie, how can we turn that into a machine that is objective rather than just based on a single person's observations.

Speaker 3 So those are the real seeds of the polygraph.

Speaker 1 When did it start getting used in police work?

Speaker 1 I mean, seriously used in police work where, you know, let's hook this guy up to the machine and tell him and figure out whether he's telling the truth or not.

Speaker 3 Funnily enough, actually, for the first couple of years, it was mainly let's hook this girl up to the machine rather than this guy.

Speaker 3 So the first cases were in 1921 and they were overwhelmingly looking at like dormitory thefts at the University of Berkeley so that was the first case of the polygraph it was um there was a woman's only dorm in Berkeley and a bunch of stuff had gone missing like jewelry and cash and books and things like that and this was the first case where the Berkeley Police Department were kind of called in to run polygraph tests on all these young women uh to try and find out who did it and so John Larson went along with his machine and he ran tests on all these women including the woman who stuff the woman whose stuff had been stolen to begin with.

Speaker 3 And

Speaker 3 eventually he came across a woman who blew up when the machine was connected to her, refused to answer any more questions. And he kind of thought, well, she's the one who did it.

Speaker 1 How widespread is the use of the polygraph? I mean, is it used a lot or is it mostly in movies and occasionally

Speaker 1 here and there? I mean, how well accepted is it?

Speaker 3 The most recent estimates I have suggest that there are about 3 million lie detector tests a year in the United States. It's used much more heavily in some countries than others.

Speaker 3 So the US is a very, very heavy user of the polygraph. Japan is another one.

Speaker 3 So yes, it was used and it is used, it's still used by government departments, you know, intelligence agencies and things like that.

Speaker 3 But it's also used by police departments where they want to get a confession from someone without necessarily having to like take a case to trial.

Speaker 3 It's a much cheaper way of extracting a confession from someone if you think they're guilty than having to go through the sort of expense and process of actually taking them to trial.

Speaker 3 So it is still used quite widely, and you see this in kind of true crime documentaries all the time, where the polygraph invariably pops up at some point in the investigation.

Speaker 3 Its heyday was really in the kind of 20s, 30s, 40s, and 50s, I think. So after Larson did these tests on women in college dorms, then they quickly started, you know, testing suspected murderers.

Speaker 3 And then it kind of snowballed from there with the help of a guy called Leonard Keeler, who was a high school student who really helped to popularize the machine.

Speaker 2 Well, how accurate is it?

Speaker 1 If you take all the results of a polygraph, I mean, are you ever able to say, well, you know, it's 50-50. I mean, and if it's 50-50, what good is it?

Speaker 3 Yeah, so the estimates range from

Speaker 3 as high as 85 to 90% to as low as 60 to 65%.

Speaker 3 So it's not much better than tossing a coin. And studies show that actually, as individuals, we can get it.
We can tell when someone's lying about 54% of the time.

Speaker 3 So it's only slightly better than just human intuition.

Speaker 3 And I guess this comes to the second point, which is it's not really possible to actually assess how accurate the polygraph is when it comes to criminal investigations because you never actually know what really happened.

Speaker 3 Say someone gets found guilty with the polygraph, then gets found guilty by a jury and gets sent to prison. That doesn't necessarily mean they were guilty.
So you can never really know.

Speaker 3 All you can really tell is that in this case, the polygraph agreed with the jury. In this case, the polygraph didn't agree with the jury.
But juries are

Speaker 3 fallible as well. So you can never really tell how accurate the polygraph actually is in the real world rather than in lab studies.

Speaker 1 Well, what are the things that a polygraph machine is measuring? When we see the little needle on the paper,

Speaker 1 what's sending the needle

Speaker 1 up and down or not moving much? Or what's it measuring?

Speaker 3 Perhaps the easiest way to visualize this is by talking through the equipment that you have attached to you when you have a polygraph test done.

Speaker 3 So the first thing that you'll notice is there's a blood pressure cuff wrapped around your arm. So that's measuring your pulse and also your blood pressure.

Speaker 3 So how fast your heart is beating and what your blood pressure is doing at the same time.

Speaker 3 Then the second thing you'll have is you'll have two bands wrapped around your chest, one to measure your breathing around around the kind of higher, higher up your chest and then one around your diaphragm for lower down.

Speaker 3 And those are measuring your breathing rate. So how fast you're taking in air and it's thought that

Speaker 3 liars might hold their breath while they're formulating a response to a question that they know they're going to have to lie on, or things like that.

Speaker 3 And then the final thing is called galvanic skin response, which is basically sweat. So, this is usually attached to the fingertip, and this measures how much you're sweating.

Speaker 3 So, each of those measurements will have a corresponding line on the polygraph chart, and then the examiners will learn to interpret those lines in tandem to look for kind of signs of what they consider to be lying.

Speaker 1 And do each one of those things have its own little needle?

Speaker 3 Yeah, that's right. Yeah.
So, and actually, the technology hasn't changed since,

Speaker 3 you know, the 1920s, really. So, in the initial one,

Speaker 3 yeah, you'd have four different lines on the chart, and then it's the kind of combination of those lines that will appear on the chart, you know, ink on paper or nowadays it's on a computer screen.

Speaker 1 So, my sense is if somebody were to hook me up to one of those machines and, you know, strap things around my chest and a blood pressure cuff, that I would, that my blood pressure would go up just because of the experience of having to do this test and people suspecting I'm lying, that just being there would make me look like a liar.

Speaker 3 Exactly. The machine is supposed to work on the premise that liars will be nervous, but people are nervous for all sorts of reasons, right?

Speaker 3 There's no way of telling whether someone is sweaty because they're lying or sweaty because they're nervous about being wrongly accused of lying.

Speaker 1 Or maybe they're lying.

Speaker 3 Or maybe they're lying, yeah. But you just can't tell.
And that's the big problem with the polygraph.

Speaker 3 You know, even if 90% of people would show a particular result on the polygraph, that doesn't mean it's true for everyone. And that's the big problem.

Speaker 3 There's no single telltale sign of lying that works for everyone all of the time. Researchers in the field say there's no Pinocchio's nose.

Speaker 3 You know, there's nothing that is going to give you the right answer with enough certainty enough times to be valid to use in a courtroom setting, for instance.

Speaker 1 At what point did people, I mean, was it assumed more or less from the beginning that this was

Speaker 1 pretty accurate and then somebody showed that it wasn't? Or were people skeptical from the beginning? Or how did it kind of fall out of favor to the extent that courts won't use it?

Speaker 3 So it's actually been barred from the courtroom for a really, really long time.

Speaker 3 So Larson invented the machine in 1921, and there was a famous case called the Fry case, which was set a precedent that the polygraph couldn't be used in the courtroom.

Speaker 3 And that was actually in, I think, 1923. So it really wasn't long afterwards.

Speaker 3 But even the people that invented the polygraph kind of had their misgivings about it quite early on and thought that it shouldn't have been used as widely as it was and was being used even back then.

Speaker 3 So John Larson, who invented it, was really excited about it for the first couple of years. but then he saw how his scientific caution kind of got blown away by hype and press coverage.

Speaker 3 And then by the end of his life, he hated the machine. He thought it was like a Frankenstein's monster that he'd unleashed on the world.

Speaker 3 So, I would say that within 10 years, there were serious doubts about the efficacy of the polygraph. But by then, the hype and the

Speaker 3 drama around it sort of overtook it all, and it really snowballed

Speaker 1 the guy or the woman who's operating the machine and then asking the questions it would seem that the results might be open to interpretation that one one person might administer a test and say one thing and another person might interpret it another way or is it an objective result

Speaker 3 it's very very subjective so yes you can give two different examiners the same chart to examine and they could come up with completely different answers as to whether the person was lying

Speaker 1 it almost sounds like

Speaker 1 because it is so subjective and because people are so different that

Speaker 1 it's basically worthless.

Speaker 3 Yes, essentially. That would be my contention.
I mean, I think that the machine has obviously helped to put criminals away. There's no getting around that.

Speaker 3 But the problem is that it's also perpetrated serious miscarriages of justice. Essentially, the reason the polygraph has been so successful is because of the theatre around it, right?

Speaker 3 It works because people believe it works so that the mere threat of being attached to a polygraph can compel someone to confess to the crime before the exam even takes place because they're so worried about being found out because they believe the machine works, even if it doesn't actually work.

Speaker 1 Yeah, that sounds like that's the real secret to the polygraph, that if somebody refuses to take one, maybe we better give this guy a closer look.

Speaker 3 I mean, you don't even need a polygraph machine some of the time. So there's a great story from David Simon's book about policing in Baltimore where he describes this situation.

Speaker 3 And I think it's recreated in an episode of The Wire, actually,

Speaker 3 where

Speaker 3 the police officers didn't have a holograph available.

Speaker 3 So they used a Xerox machine and they put the subject's hand on a Xerox machine and told the subject that it was a lie detector and then just got the machine to print out a piece of paper with he's lying written on it.

Speaker 3 And that was enough to kind of trick the suspect into actually, you know, believing that the machine could read their mind.

Speaker 1 Well, it does the job. It gets the guy to confess because he thinks he's in a corner, basically.

Speaker 1 exactly yes it does the job it's all about the theater of it and actually they realized this very early on the inventors of the polygraph that it was largely about the theater so they did take steps to amp that up so the people who administer the test and interpret the results what's their training what i mean if if two people can look at the same chart and come up with different results what how did they get to come up with those different results because they were trained how?

Speaker 3 Yes.

Speaker 3 So to train to become a polygraph examiner, well, there's no real regulation stopping you from just buying a polygraph machine on eBay and then advertising your services.

Speaker 3 But most polygraph examiners that are operating today have certification from something called the American Polygraph Association.

Speaker 2 However,

Speaker 3 in order to b get certification from the American Polygraph Association requires a twelve week course, I think it is. So we're talking about a few thousand dollars, a few months,

Speaker 3 and then that's it.

Speaker 1 There are other ways that people claim to be able to tell if someone is lying.

Speaker 1 And it's usually, you know, it's usually not just one thing, but if you watch somebody over a period of time and compare it to a baseline, that you can get a sense whether they're lying.

Speaker 1 And I'm wondering: has anyone ever tested the polygraph versus those kind of ways of determining deception and to see which is more accurate?

Speaker 3 Those ways of, I don't know if there's ever been a kind of a direct comparison done with the same subjects, but a lot of other methods of detecting lies have been very thoroughly tested, but they all suffer from the same sort of fatal flaw, which is you can't be sure.

Speaker 3 And with something like lie detection, you kind of need to be sure, right? If you are

Speaker 3 running someone in a murder case where the crime is, you know, capital punishment, then you need to be 100%

Speaker 3 sure

Speaker 3 that

Speaker 3 they are going to be susceptible to the particular type of lie detector you're trying to use on them.

Speaker 3 And there's no evidence to suggest that everyone will display exactly the same range of physiological responses to telling a lie.

Speaker 3 And actually, you might expect that a psychopath or a serial killer might not actually show the range of emotional responses that you would expect.

Speaker 3 So maybe those people are actually less susceptible to lie detectors than your ordinary man on the street because they already have a kind of different range of emotional responses and actually that's what we're looking for with the polygraph so it's still used today and and is it basically used because

Speaker 1 it's better than nothing

Speaker 3 yeah i think it's used because it's it's convenient so if you can get a confession from someone using the polygraph that's much cheaper than

Speaker 3 having to go out and collect all the evidence and then take the case to court and all that kind of stuff. It is slowly being superseded by different forms of lie detection in some fields.

Speaker 3 I think there's kind of new inventions that are cheaper to run than the polygraph, that don't require a trained examiner and all this kind of stuff.

Speaker 3 So, we might see it shifting away from the polygraph towards new forms of lie detection in the future. But it's convenient, people believe it works, and you know, it gets results sometimes.

Speaker 3 Actually, a lot of the time, it gets the results that the people running the test are looking for. Whether it actually gets to the truth is a kind of different question.

Speaker 1 When a polygraph test is given, it's all yes or no questions, right? It isn't so tell me about. It's strictly yes or no.

Speaker 3 That's right. The way it's portrayed in film and TV is quite wrong, actually, because it's kind of portrayed as this back and forth between the investigator and the suspect.

Speaker 3 But yes, actually, the way that the test was originally designed was, yeah, these very, very slow

Speaker 3 yes or no questions repeated multiple times over the course of several hours.

Speaker 3 The suspect gives yes or no responses because the point is you want to minimize the difference between the control questions,

Speaker 3 which are irrelevant to the crime, and the target questions, which are about the crime. So, you want the suspect to be sitting as still as possible to reduce interference.

Speaker 3 So, you don't want them to be spinning out long sentences and things like that.

Speaker 3 You want to keep the differences to a minimum so that when they do lie, it shows up on the chart, or at least that's the theory, anyway.

Speaker 1 What's pretty interesting is the polygraph has really had pretty good PR, it seems, for a long time, given the facts. I mean, it still gets used.

Speaker 1 People still believe it works, and yet there isn't a whole lot of science behind it, it seems.

Speaker 3 Yeah, that's right. It's just somehow become sort of embedded in the justice system.
And I think a lot of people have

Speaker 3 debunked it. It's been debunked by numerous academic studies, government reports, expert analysis on several occasions, but it just sort of refuses to go away.

Speaker 3 And I think that's probably something to do with human nature, right? We're drawn to this idea that a machine can reveal the truth, right? Especially in a time when truth is so difficult to find.

Speaker 3 I think this idea that there is a machine that can do it for us is still quite compelling.

Speaker 1 Well, now I think

Speaker 1 I want to get hooked up.

Speaker 1 I want to have a polygraph test just to have the experience. I've been talking with Ahmed Katwala.

Speaker 1 He is an award-winning journalist, a senior writer at Wired, and author of of the book Tremors in the Blood, Murder, Obsession, and the Birth of the Lie Detector.

Speaker 1 And you will find a link to that book in the show notes. Thank you, Ahmed.

Speaker 3 Thanks so much for having me. I appreciate it.

Speaker 1 Women drivers have gotten a bad rap over the years. Statistics show that actually they're better drivers overall than men are.

Speaker 1 Women are involved in fewer accidents, have fewer insurance claims, and don't wind up with as many moving violations as men do. And some surveys have found that women are also superior parkers.

Speaker 1 Researchers watched 2,500 drivers park and scored them on technique, precision, and time taken. The women were better at picking accessible spaces and at lining up their vehicles to park them.

Speaker 1 Women out-parked the guys in parallel parking situations as well. They were more likely to back in, which is the method preferred by driving experts.
And that is something you should know.

Speaker 1 If you enjoyed today's podcast, don't keep it to yourself. Share it with someone you know.
I'm Mike Carruthers. Thanks for listening today to Something You Should Know

Speaker 4 the Regency Era.

Speaker 4 You might know it as the time when Bridgerton takes place, or the time when Jane Austen wrote her books.

Speaker 4 But the Regency era was also an explosive time of social change, sex scandals, and maybe the worst king in British history.

Speaker 4 And on the Vulgar History podcast, we're going to be looking at the balls, the gowns, and all the scandal of the Regency era.

Speaker 4 Vulgar History is a women's history podcast, and our Regency Era series will be focusing on the most rebellious women of this time.

Speaker 4 That includes Jane Austen herself, who is maybe more radical than you might have thought.

Speaker 4 We'll also be talking about queer icons like Anne Lister, scientists like Mary Anning and Ada Lovelace, as well as other scandalous actresses, royal mistresses, rebellious princesses, and other lesser-known figures who made history happen in England in the Regency era.

Speaker 4 Listen to Vulgar History wherever you get podcasts.

Speaker 1 The Infinite Monkey Cage returns imminently. I'm Robin Ins, and I've sat next to Brian Cox, who has so much to tell you about what's on the new series.

Speaker 2 Primarily eels.

Speaker 1 And what else?

Speaker 1 It was fascinating, though, the eels. But we're not just doing eels, are we? We're doing a bit.

Speaker 1 Brain-computer interfaces, timekeeping, fusion, monkey business, cloud signs of the North Pole, and eels. Did I mention the eels? Is this ever since you bought that timeshare underneath the Sagasso C?

Speaker 1 Listen on bbc.com or wherever you get your podcasts.