May 11, 2019 • 28 mins
Instead of actually detecting lies, polygraph machines sense physiological variations, ostensibly brought on by guilt. The results are subject to interpretation, and therefore controversial. Join Josh and Chuck as they investigate the polygraph.
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Episode Transcript
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Speaker 1 (00:00):
Hello there, it's me Josh and for this week's s
Y s K Selects, I've chosen our classic episode on
Lie Detectors. It's a pretty nifty little episode about a
pretty dodgy piece of forensic science with a wow of
a backstory. It is classic stuff you should know, so
I hope you enjoy. Welcome to Stuff you Should Know,
(00:24):
a production of My Heart Radios How Stuff Works. Hey,
and welcome to the podcast. I'm Josh Clark. With me
is always as Charles to be Chuck Bryant liar you
you could tell there's the ways you can find out
Chuck Um. We'll get to that in a minute. This
(00:46):
is stuff you should know. Let me finish, Okay, and
it's you lie. Remember that guy, Yeah, Joe joey Pants
or whatever the congressman's name. Yeah, Saturday Night Live a
funny skit that he had gotten a whole group of
people to all stayed up at once, wasn't the deal?
Tell it? And well, yeah, and he supposed he had
a whole group of senators that we're gonna all stand
(01:07):
up and yell you lie. And then he was the
only one that did it. That's because he was out
of the room when they were like, no, we can't
do that, that's funny. Yeah. So um, oh, we're talking
about a lot of detectors. But let me take you back,
all right to a little place in time and space
called the jazz age early nineteen twenties. Yeah. No, that's
(01:33):
the beat Knicks that did that. Okay, Um, I'm sure
a jazz person snapped their fingers at one point. Sure, um,
but not like that, all right. It was more like
like Coltrane style, just like that. Anyway. This is Chuck
in Berkeley, California, at u c l A, Berkeley, And
(01:54):
there is a place there called, um, the College Hall,
which was a women's dorm. And in that year there
were a theft, a string of there was a string
of um thefts, cash rings, um, pretty much anything of
value went missing for a little while there. And uh,
(02:16):
there's a man working at the Berkeley Police Department in
the girl's dorm. Yeah, okay, called College Hall. There was
a man working in the in the Berkeley Police Department's
name is John Larson. And John Larson was the first
cop ever to have a pH d. And he had
gotten interested in this device called a cardio neumo psychograph
(02:40):
which had been invented just a few years before by
another guy named William Marston. And William Marston was a
lawyer in a Harvard shrink and he also as an
aside creative wonder Woman with her Lasso of truth. Really,
he's the guy who invented the what's now called the polygraph.
What about the wonder Woman? He created Wonder Woman, the character.
(03:04):
He was kind of a renaissance man. But that's William Marston.
John Larson works at the at the Berkeley Police Department
and he's become interested in this thing, the cardio neumo psychograph,
and he realizes, okay, this is a perfect chance to
apply it. So he rounds up, you know, some suspects.
He does some some normal police work and finds out
who the suspects are in this in this hall, and
(03:27):
he rounds him up, brings him down the station, and
he starts hooking people up to this um this machine.
And he gets to this one woman, her name is
Helen Graham, and guilty, yes, pretty much is what he does.
He goes, ms. Graham, this machine is saying that you're
that you took this, that you you took the money,
you know, did you? Um and he said that he
(03:48):
noted on the machine a sharp dropping blood pressure followed
by a sudden rise. And then after that this woman
flew into a rage. She tried to attack the machine.
She went crazy. So they they basically stringer along for
a few days, and then finally she confesses, and it's
the first time that a polygraph was ever used to
to um solve a crime. Ever, that that was probably
(04:11):
the heyday because before the people knew what it was,
they could just say this machine says that you're guilty,
and they would be like, oh my god, that's exactly right.
Very early on, some of the early proponents, specifically a
guy named a Leonard Keeler, um recognized the placebo effect
value before anyone knew there was a placebo effect, but
the placebo effect value of a polygraph. That just the idea,
(04:35):
if you believed in this machine and that it could
rude outlies, then it could force you to confess just
being hooked up to it. You weren't going to pass it.
They should have called it the guilt box. They called
it the magic lie detector is one of the one
of the things that they called it. Yeah, Leonard Keeler
called it that he worked with John Larson at the
Berkeley Police Department, and eventually, over time John Larson saw
(04:58):
the what he considered the true youth behind the light
detector and the fact that it kept being cold light detector,
which is driving him crazy. Um, and he eventually distanced
himself from it later on in his career. Um, but
Leonard Keeler ran around marketing it to anyone and everyone saying,
just having this is going to not only help you
hire um, more more truthful, forthright people, but it's going
(05:23):
to keep them in line while they're working for you,
because they know you've got access to this thing and
you can strap them to it at any time. Yeah,
so that's where the polygraph came from. Yeah, there's a
little prehistory to just to give them their due. Uh.
In eight Cesaire Lambroso, he's an Italian criminologist. He measured
changes in blood pressure for police cases. In a nineteen
(05:45):
o four a device by Vittorio Binosi measured breathing and
so they were early nineteen hundreds, late eighteen hundreds. They
were kind of on the scene of of measuring these things.
And Dr James Mackenzie in nineteen o six first mentioned
the word polygraph with his instrument that he didn't use
(06:05):
to root out the truth, but for uh he did
use it when giving medical examination though. And then right
before the polygraph was the unigraph unigraph, which was part
of what's still used today in the polygraph. Um, it
measured respiration. Pretty cool, yeah, um, but then you add
(06:26):
to it a couple of other things and you got
the polygraph. We could stop here. This is interesting enough
right now. So there's no uh you really, there's no um,
no one walking the planet who has anything to do
with polygraphs that call them lie detectors, And anyone, even
the most ardent defender of polygraph technology would correct you
(06:51):
if you called it a lie detector. They would be like,
it's it's not a lie detector because you can't detect
a lie. It's possible. The whole basis of a polygraph
is that it is a set of um medical instruments
that used to measure changes in things like your heart rate,
your respiration, UM and sweatiness. Basically, I would fail. Um, well,
(07:13):
a lot of people do fail, and we'll get to that.
But um, oh, because you're sweat that's okay. They would
they would even hook me up. Um. So when you're
hooked up to this machine, the whole point is that
it measures these physiological changes in the idea that there
(07:33):
you're going to undergo physiological changes based on the concept
that a person hooked to this machine who is guilty
will experience fear that they're going to be detected. So
this machine is designed to detect that fear. That's right,
which is really round about. But for a century almost
(07:55):
these things were used, um and abused, and it took
a while for people that to catch on that. There's
a lot to criticize here with polygraphs, Yeah, for sure.
(08:24):
All right, so let's get into this um. First of all,
we need to point out that analog polygraphs are what
you have long seen in movies and TV when they
have the little jittery looks like a seismograph on the
on the paper scrolling by, and uh, you're hooked up
to all these different things on your chest, in your
forehead and your fingertips. These days they do that digitally,
(08:47):
but it's basically still the same technique. They just don't
use the little scrolling needle. Do They have a name
for that. It's called an inkfield pen. It is. Yeah.
But the three things that they do, Josh, They measure
your respiratory rate, as you said, They take newmgraphs, which
are rubber tubes filled with air time around your chest
(09:10):
and your abdomen, and that is going to measure whether
or not you're you know, you start breathing heavy essentially
when you get nervous. It monitors your breathing pattern and
any changes to it, and it does it pretty cleverly. Right. Yeah.
With bellows, it they're filled with air. So when you
when you breathe in real deeply or have a change,
it's going to displace that into the bellows and that
(09:31):
will Originally that was attached, the bellows were literally attached
to the mechanical arm that showed the change. These days,
as a it's a transducer that converts it digitally electronically, right,
it converts it to an electrical pattern, right, Yeah, that
probably just says for the same thing. Yeah, um no,
I think it looks a lot like it if you look.
(09:52):
There's a picture of a modern one and it looks
just like But yeah, it's not. It's not a paper
read out any longer, which is kind of interesting. Like
this technology hasn't hasn't changed on a very fundamental basis
for like a hundred years almost. Yeah, I mean the
early one from Mackenzie in nineteen o six. They say
that a lot of the same components are still very
(10:13):
similar today. Right. Um. You also are going to have
so you're gonna have two tubes, one around your chest,
one around your abdomen. It's um keeping an eye on
your breathing. Um. You're going to have a blood pressure
cuff which um, which keeps an eye on your heart
rate and your blood pressure, and it does it through sound, right. Yeah,
(10:34):
I didn't realize this. So when you're when the blood
comes in and out of your veins, it creates sound,
and sound can also be used to displace air, causing
a bellows to contract, which again moved the arm on
the scroll and now is created or turned into an
electrical pattern. Um, but it's the same thing, but it's sound,
(10:56):
which I just think is very neat. Well, and what's
also neat is the sweat one. I figured they would
have some sort of like a moisturerometer just to detect moisture,
but it's called galvanic skin resistance or GSR or electrodermal activity,
that's right. And they hook up these fingerplates to galvanometers
and they are basically measuring the skin's ability to conduct electricity.
(11:20):
And if your skin is moist, it's going to be
able to conduct electricity easier. And that's what they're measuring there.
It's like the ones the little um heart rate monitors
that they clip to your fingertips in the hospital, but
these things measure electricity instead, uh, which if you are dry,
(11:40):
you're going to conduct less electricity, if you're wet, you're
going to conduct more. So since you have so many
pores on the end of your fingers and you sweat
when you're nervous. There you got done. So you put
all this together and um, it paints this picture. It's
the A. C. L U among other people, have decried
as just what are you doing here? Basically is what
(12:04):
the A C l U says, right, Um, what what
you have is a picture of a person who is
undergoing stress, maybe feeling embarrassment, is maybe just scared to
be there, uh, maybe doesn't like having things wrapped around
his or her chest. Um, maybe doesn't really like the
(12:27):
person asking the questions. The results of these these UM
changes in pattern. The data is totally subjective, that's right,
which makes polygraphs totally subjective, which takes it in large
part out of the realm of science. Yeah, voodoo science
is what they call it. And uh, all the proponents
(12:48):
will say that a well trained forensic psychophysiologists which is
the examiner, can get through all that to still get
a good result. They're like, yeah, they know all this stuff,
and if you're good, then you can factor that in
and still get a good result. So let's talk about
what the forensic psychophysiologist does. There's apparently I've seen anywhere
(13:10):
between five thousand and ten thousand of them in the
US at any given time, UM, and some of them
belong to professional organizations. I think probably maybe half or third,
depending on where you are on the on the estimate,
UM belonged to any number of professional organizations. Some have
(13:32):
no accreditation whatsoever, um, but are still able to open
up shops depending on the state there in. Some states
have zero laws about being a forensic psychophysiologist a k
A polygraph examiner. That's right, but there is also some
there are programs out there. Uh. The who wrote this article,
Kevin bondser I don't know. I think so he he
(13:54):
UM interviewed a guy who founded the Accidon Academy exit
Haunt as a manufacturer of polygraphs, and they founded this
academy as well, where um, you go through a certain
amount of training to become a forensic psychophysiologist. And he
actually interviewed that guy. Yeah, his name's Bobb Lee Lee. Uh,
(14:16):
and Lee says that if you come to their academy, UM,
you have to have a baccalaurea degree bachelor's right, or
you have to have at least five years investigative experience
and an associate's degree. Um, you have to take a
ten week course, and after you complete the ten week course,
you have to carry out twenty five polygraph examinations and
(14:39):
submit them to be reviewed. Uh. So these are like
real life ones. I guess you're working with your local
police department or whatever. Maybe you're already a cop UM
and you have to submit it to the Accident Academy
board for a review. And then once they're all reviewed
and everybody's all thumbs up, you are a life since
(15:00):
I guess. But you're not licensed because there's no licensing body. Um,
you are you graduate? I guess is is what they
call it. So that's as accredited as it gets. I guess.
And like you said, Um, proponents of polygraph testing say
that there, if you're a good FP, you're gonna be
(15:22):
able to structure everything correctly so that you can see
past somebody who's just who sweats a lot like you,
or who gets stressed out easily like me, Um, and
design your questions appropriately, and you're gonna be able to
to to figure out whether this person is deceptive or not.
So how how would you do that? Chuck? Well, we
(15:43):
should talk about the test itself. I guess. Uh, you're
gonna you're gonna go in and you're gonna get a
pretest before you get strapped up to anything. Could take
about an hour. This is just you and those the
only two people in the room. You're not surrounded by
folks like in the movies and stuff, although a movie
sometimes it's just two people, I guess. But the pretest
that you're just going to get an interview basically about
(16:06):
basically about why you're being investigated. Uh, they're also gonna
be profiling you and checking you out and just seeing
what kind of questions you respond to and what might
make you nervous, just so they'll be better informed about
how to properly question you once you're all strapped in
right and the pretest where you're just kind of hanging
out with them casually, the examiners also kind of getting
(16:28):
info out of you that you might not be aware of, like, um,
if you are uh, if you talk leisurely about your
favorite beer at one point and how you like it
a lot, and then later on it also comes up
that you have to drive a lot um, they might
come up with it. They might use that for a
control question, UM, which could be something like have you
(16:49):
ever driven under the influence of alcohol? And a control
question is something where you would have to admit guilt um,
and you may not want to, but it's such a
broad question that just about anybody is guilty of it,
like have you ever lied to somebody? Have you ever
um stolen anything? That kind of thing, So where if
you say no, they now have a baseline for what
(17:12):
it looks like when you lie. That they can make
a reasonable assumption that you have just lied. And any
of the data UM captured on the polygraph they're going
to use to analyze everything else off of. And that's
pretty much it. That's the test, and afterward you have
the post tests where they look at all the data
(17:33):
and chart out whether or not they think you're deceptive
and aware. Like on this question you were deceptive. On
this question you may have been deceptive. It's kind of
hard to tell. On this one you definitely were deceptive.
So so, and it's all in it's all in relation
to that control question, that baseline, right, So if you
if your deception, if you if on questions where I mean,
(17:56):
they're going to have to talk to the police as
well too and say what do you want to know
out of this person? So they'll design questions around that
as well. Um, so they may have a question like, um,
are you wearing a blue shirt? That may be question one,
it's irrelevant, right. Question two is, um, have you ever
lied to your boss? That's the control question, and then
question three is something like you know, did you steal
(18:19):
the cookie from the cookie jar? Like that's the one
that the cops want them to ask. They'll compare the
results of Q three against Q two and if they're
the same or you can't really tell, that's in UH
in that that's an UH inconclusive tests. So that's it.
I mean, like you said, that's that's polygraph. It's pretty easy,
(18:57):
it is. It's Uh, it's um jar ringly easy, considering
that it's used in legal cases a lot, right, Yes,
that's true. Um. People try to to battle the LDE
detector in various ways or a little tricks that the
Internet says works, like taking a sedative or putting any
perspirint on your fingers, which seems like they would make
(19:18):
you wash your hands, Uh, putting attack in your shoe,
and anytime you get asked a question, every single time
you stomp on the tack. And the idea is that
you're just gonna skew the tests so they all look
the same, so your body has the same reaction no
matter what's going on, like they I guess, if you
press on the tack, your physiological response could overwhelm any
(19:39):
response to the question. Right. Um, Like I said, there,
these these things are used in legal cases, but with caveats. Right.
If you undergo a polygraph, Uh, whether you fail or pass,
it doesn't really matter legally speaking, right, um, because of
(20:01):
unless you're in New Mexico. Yeah, this is the only
state that allows it just openly. Like if you take
a polygraph like, it's admissible in court yeah, every other state. Um.
Usually the both sides have to agree on it being
admitted or um. The judge has to say, yeah, we're
gonna admit this one, right, Yeah. And federally, the judge
decides whether or not they're going to admit it, right,
(20:24):
And I guess state judges kind of follow that federal
ruling of polygraphing. Yeah, And it's sort of a crapshoot
if a federal judge is gonna allow it or not.
There's no precedent really to where they say we have
to or we don't have to. Right. So, what are
the problems with this um? The problems with a polygraph
(20:47):
um or that it's subjective, Right, that's a big one.
But also because there because it's subjective, you can get
what are called false positives and false negatives. Yeah, and
you don't want that because then the test itself is
just not valid. Right. Uh. But I mean that a
lot of people use that as evidence that polygraph polygraphy
(21:09):
shouldn't be done at all, that it's not valid. False
positive and polygraph thing is when you find somebody who
is deemed deceptive but was telling the truth. False negative
is when somebody who wasn't telling the truth UM is
deemed truthful. Like Gary Ridgeway, the Green River killer. They
(21:30):
had him for a little while and gave him a
polygraph and he passed and they let him go and
he went and killed a bunch more women. All right,
that's right. I didn't know that. Actually, Yeah, there's also
the uh. You know, the federal government is the largest
uh consumer of these exams, and if you work for
the federal government, you've probably had one to get the job.
But you can't do that in the private sector thanks
(21:51):
to the Polygraph Protection Act Employee Polygraph Protection Act in
the late eighties, they said, you can't force your employees
to do this US. You can request it, but if
they don't want to do it, you can't fire them
because of it. You just can't do it, right, not
in private land, right unless you have a contract with
the government, and then that's not valid. But yeah, the
(22:14):
the federal government is the largest opponent to him in court,
but also the largest consumer. And imagine that, UM. And
there's been a lot of cases that shaped its admissibility
or not. But the polygraph it seems like it's kind
of honest way out. I wrote an article about UM
M R I being used as lie detectors, and that's
(22:35):
starting to kind of come into fashion the more we
start to understand, like how lies are born in the brain,
being able to see it and saying this is the
pattern that will happen. UM. If this person is lying
and then that pattern happens, they say, what, we know
you're lying. We just saw that live form in your brain.
That makes sense, yes, But at the same time, people
who understand MR eyes say, is way too early to
(22:59):
be doing that. And even if we can do it
with accuracy, there are a lot of moral and ethical
questions to it as well that we need to address.
First always uh and then penile plus demography. What's that? So?
Remember the the UM newmeographs that go around the chest
and the abdomen. Imagine one of those that goes around
(23:22):
the penis and it does the same thing. It the
text changes in contraction and girth. It's a perfect way
to put it UM and it's used to detect arousal.
They use it for UM sex offenders. It's under at
least as much attack as regular UM polygraphs. But I
(23:42):
wrote this blog post called UM using science to root
out late in homosexuality among homophobes. A study at U
g A used UH penile pleas plesismography UM to find
if anyone who they had deemed homophobic be came aroused
to inexposed to homosexual pornography. Yeah, it's it's one of
(24:06):
the better posts I've ever written. Cheese, all right, that's
our future. I guess peno pleathismography for everyone, everyone with
a penis at least and then chuck. Lastly, I want
to encourage everybody, if this has piqued your interest about
lie detectors, to go watch the shoe Court shoe store
(24:26):
job interview clip from Mr Show on YouTube. You remember
that one. It's very good weather friend Paula Thompkins and
he has a breakthrough. Was seeing that one? Yeah, yeah,
good old p f T yep. And that's it for
lie detectors, right, Yeah. I want to take a test.
If there's someone in the Atlanta area that administers these
and would be willing to give me a lie detector test,
(24:49):
I would love to do that, Okay, and I'll watch
yes UM as long as I can, you know, approve
the questions or not approve them. But I don't want
to be like rooted out as some miscreant. That's a
little late for that. Just keep it above board. UM.
If you want to know more about lie detectors and
(25:10):
play with some Lie detector flash animation, you can do
that by typing in lie detector on this in the
search bar on how stuff works dot com and UM,
that means it's time for listener mail. That's right, Josh.
This is from Brad and Brad. If you remember, we
had a list of suggestions from a listener not too
(25:31):
long ago that thought our podcast could be a lot
better if we changed a few things. Brad has some
suggestions of his own of how we can make the
podcast better. We should both have nicknames zazz up the
actual name like welcome to stuff you should Know with
j C and the Dingo, sit back while getting a
big helping of knowledge from Chucko and the Duck. I
(25:54):
second the suggestion to remove the personal anecdotes should be
moved to a separate podcast called the Josh and Chuck Memoirs.
Daily one hour podcasts can recount your lives from birth
to present, focusing on depressing stories that are marginally factual.
It's in development, Chuck, please your raise your voice one octave,
Josh lower yours one octave. What okay? So now this
(26:18):
is how I talk to the opening of the podcast
should be a description of what each of you ate
that day and the number of trips to the bathroom.
This allows the listener to keep track at home. Hedgehogs,
brain surgeons, arcades, and Bolivian politics are underrated, under sorry,
underrepresented on your podcast at least should be about these subjects.
(26:40):
Do not exclude listener mail. Instead, create a quieter audio
track reading the listener mail and overlay it on the
rest of the podcast. That way, listeners can hear both
the mail and the main content at the same time.
This is a pretty good idea. Why not set the
pod we literally driving people in Spain? If we did that,
why not set the podcast to a backdrop of tribal
(27:01):
drums and jungle animal noises would give it an exotic feel.
That's over the listener mail track, over the whole thing,
So that'd be three tracks deep. Yes, and it would
lead to suspense for the listener to wonder if you
will be eaten by jaguars? Uh. And it was clear
from the podcast on Mummies neither of you had ever
been mummified. Please refrain from explaining topics that you don't
(27:23):
have personal experience with. And then the final suggestion, just
retail episodes of this American Life that went that last
one went down like the Dave Glitterman top. Finally, so
that's Brad, Thanks brand. Those are all great ideas. Three
tracks all in one, streaming at once together listener mail
quietly to podcast and tribal drumming and jungle noises. Yes, um,
(27:48):
let's see. If you have access to a polygraph and
want to hook chuck up to it, let us know.
You can let us know on Facebook at facebook dot com,
slash stuff you Should Know, You can tweet to set
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works dot com. Stuff you Should Know is a production
(28:12):
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or wherever you listen to your favorite shows
Hello there, it's me Josh and for this week's s
Y s K Selects, I've chosen our classic episode on
Lie Detectors. It's a pretty nifty little episode about a
pretty dodgy piece of forensic science with a wow of
a backstory. It is classic stuff you should know, so
I hope you enjoy. Welcome to Stuff you Should Know,
(00:24):
a production of My Heart Radios How Stuff Works. Hey,
and welcome to the podcast. I'm Josh Clark. With me
is always as Charles to be Chuck Bryant liar you
you could tell there's the ways you can find out
Chuck Um. We'll get to that in a minute. This
(00:46):
is stuff you should know. Let me finish, Okay, and
it's you lie. Remember that guy, Yeah, Joe joey Pants
or whatever the congressman's name. Yeah, Saturday Night Live a
funny skit that he had gotten a whole group of
people to all stayed up at once, wasn't the deal?
Tell it? And well, yeah, and he supposed he had
a whole group of senators that we're gonna all stand
(01:07):
up and yell you lie. And then he was the
only one that did it. That's because he was out
of the room when they were like, no, we can't
do that, that's funny. Yeah. So um, oh, we're talking
about a lot of detectors. But let me take you back,
all right to a little place in time and space
called the jazz age early nineteen twenties. Yeah. No, that's
(01:33):
the beat Knicks that did that. Okay, Um, I'm sure
a jazz person snapped their fingers at one point. Sure, um,
but not like that, all right. It was more like
like Coltrane style, just like that. Anyway. This is Chuck
in Berkeley, California, at u c l A, Berkeley, And
(01:54):
there is a place there called, um, the College Hall,
which was a women's dorm. And in that year there
were a theft, a string of there was a string
of um thefts, cash rings, um, pretty much anything of
value went missing for a little while there. And uh,
(02:16):
there's a man working at the Berkeley Police Department in
the girl's dorm. Yeah, okay, called College Hall. There was
a man working in the in the Berkeley Police Department's
name is John Larson. And John Larson was the first
cop ever to have a pH d. And he had
gotten interested in this device called a cardio neumo psychograph
(02:40):
which had been invented just a few years before by
another guy named William Marston. And William Marston was a
lawyer in a Harvard shrink and he also as an
aside creative wonder Woman with her Lasso of truth. Really,
he's the guy who invented the what's now called the polygraph.
What about the wonder Woman? He created Wonder Woman, the character.
(03:04):
He was kind of a renaissance man. But that's William Marston.
John Larson works at the at the Berkeley Police Department
and he's become interested in this thing, the cardio neumo psychograph,
and he realizes, okay, this is a perfect chance to
apply it. So he rounds up, you know, some suspects.
He does some some normal police work and finds out
who the suspects are in this in this hall, and
(03:27):
he rounds him up, brings him down the station, and
he starts hooking people up to this um this machine.
And he gets to this one woman, her name is
Helen Graham, and guilty, yes, pretty much is what he does.
He goes, ms. Graham, this machine is saying that you're
that you took this, that you you took the money,
you know, did you? Um and he said that he
(03:48):
noted on the machine a sharp dropping blood pressure followed
by a sudden rise. And then after that this woman
flew into a rage. She tried to attack the machine.
She went crazy. So they they basically stringer along for
a few days, and then finally she confesses, and it's
the first time that a polygraph was ever used to
to um solve a crime. Ever, that that was probably
(04:11):
the heyday because before the people knew what it was,
they could just say this machine says that you're guilty,
and they would be like, oh my god, that's exactly right.
Very early on, some of the early proponents, specifically a
guy named a Leonard Keeler, um recognized the placebo effect
value before anyone knew there was a placebo effect, but
the placebo effect value of a polygraph. That just the idea,
(04:35):
if you believed in this machine and that it could
rude outlies, then it could force you to confess just
being hooked up to it. You weren't going to pass it.
They should have called it the guilt box. They called
it the magic lie detector is one of the one
of the things that they called it. Yeah, Leonard Keeler
called it that he worked with John Larson at the
Berkeley Police Department, and eventually, over time John Larson saw
(04:58):
the what he considered the true youth behind the light
detector and the fact that it kept being cold light detector,
which is driving him crazy. Um, and he eventually distanced
himself from it later on in his career. Um, but
Leonard Keeler ran around marketing it to anyone and everyone saying,
just having this is going to not only help you
hire um, more more truthful, forthright people, but it's going
(05:23):
to keep them in line while they're working for you,
because they know you've got access to this thing and
you can strap them to it at any time. Yeah,
so that's where the polygraph came from. Yeah, there's a
little prehistory to just to give them their due. Uh.
In eight Cesaire Lambroso, he's an Italian criminologist. He measured
changes in blood pressure for police cases. In a nineteen
(05:45):
o four a device by Vittorio Binosi measured breathing and
so they were early nineteen hundreds, late eighteen hundreds. They
were kind of on the scene of of measuring these things.
And Dr James Mackenzie in nineteen o six first mentioned
the word polygraph with his instrument that he didn't use
(06:05):
to root out the truth, but for uh he did
use it when giving medical examination though. And then right
before the polygraph was the unigraph unigraph, which was part
of what's still used today in the polygraph. Um, it
measured respiration. Pretty cool, yeah, um, but then you add
(06:26):
to it a couple of other things and you got
the polygraph. We could stop here. This is interesting enough
right now. So there's no uh you really, there's no um,
no one walking the planet who has anything to do
with polygraphs that call them lie detectors, And anyone, even
the most ardent defender of polygraph technology would correct you
(06:51):
if you called it a lie detector. They would be like,
it's it's not a lie detector because you can't detect
a lie. It's possible. The whole basis of a polygraph
is that it is a set of um medical instruments
that used to measure changes in things like your heart rate,
your respiration, UM and sweatiness. Basically, I would fail. Um, well,
(07:13):
a lot of people do fail, and we'll get to that.
But um, oh, because you're sweat that's okay. They would
they would even hook me up. Um. So when you're
hooked up to this machine, the whole point is that
it measures these physiological changes in the idea that there
(07:33):
you're going to undergo physiological changes based on the concept
that a person hooked to this machine who is guilty
will experience fear that they're going to be detected. So
this machine is designed to detect that fear. That's right,
which is really round about. But for a century almost
(07:55):
these things were used, um and abused, and it took
a while for people that to catch on that. There's
a lot to criticize here with polygraphs, Yeah, for sure.
(08:24):
All right, so let's get into this um. First of all,
we need to point out that analog polygraphs are what
you have long seen in movies and TV when they
have the little jittery looks like a seismograph on the
on the paper scrolling by, and uh, you're hooked up
to all these different things on your chest, in your
forehead and your fingertips. These days they do that digitally,
(08:47):
but it's basically still the same technique. They just don't
use the little scrolling needle. Do They have a name
for that. It's called an inkfield pen. It is. Yeah.
But the three things that they do, Josh, They measure
your respiratory rate, as you said, They take newmgraphs, which
are rubber tubes filled with air time around your chest
(09:10):
and your abdomen, and that is going to measure whether
or not you're you know, you start breathing heavy essentially
when you get nervous. It monitors your breathing pattern and
any changes to it, and it does it pretty cleverly. Right. Yeah.
With bellows, it they're filled with air. So when you
when you breathe in real deeply or have a change,
it's going to displace that into the bellows and that
(09:31):
will Originally that was attached, the bellows were literally attached
to the mechanical arm that showed the change. These days,
as a it's a transducer that converts it digitally electronically, right,
it converts it to an electrical pattern, right, Yeah, that
probably just says for the same thing. Yeah, um no,
I think it looks a lot like it if you look.
(09:52):
There's a picture of a modern one and it looks
just like But yeah, it's not. It's not a paper
read out any longer, which is kind of interesting. Like
this technology hasn't hasn't changed on a very fundamental basis
for like a hundred years almost. Yeah, I mean the
early one from Mackenzie in nineteen o six. They say
that a lot of the same components are still very
(10:13):
similar today. Right. Um. You also are going to have
so you're gonna have two tubes, one around your chest,
one around your abdomen. It's um keeping an eye on
your breathing. Um. You're going to have a blood pressure
cuff which um, which keeps an eye on your heart
rate and your blood pressure, and it does it through sound, right. Yeah,
(10:34):
I didn't realize this. So when you're when the blood
comes in and out of your veins, it creates sound,
and sound can also be used to displace air, causing
a bellows to contract, which again moved the arm on
the scroll and now is created or turned into an
electrical pattern. Um, but it's the same thing, but it's sound,
(10:56):
which I just think is very neat. Well, and what's
also neat is the sweat one. I figured they would
have some sort of like a moisturerometer just to detect moisture,
but it's called galvanic skin resistance or GSR or electrodermal activity,
that's right. And they hook up these fingerplates to galvanometers
and they are basically measuring the skin's ability to conduct electricity.
(11:20):
And if your skin is moist, it's going to be
able to conduct electricity easier. And that's what they're measuring there.
It's like the ones the little um heart rate monitors
that they clip to your fingertips in the hospital, but
these things measure electricity instead, uh, which if you are dry,
(11:40):
you're going to conduct less electricity, if you're wet, you're
going to conduct more. So since you have so many
pores on the end of your fingers and you sweat
when you're nervous. There you got done. So you put
all this together and um, it paints this picture. It's
the A. C. L U among other people, have decried
as just what are you doing here? Basically is what
(12:04):
the A C l U says, right, Um, what what
you have is a picture of a person who is
undergoing stress, maybe feeling embarrassment, is maybe just scared to
be there, uh, maybe doesn't like having things wrapped around
his or her chest. Um, maybe doesn't really like the
(12:27):
person asking the questions. The results of these these UM
changes in pattern. The data is totally subjective, that's right,
which makes polygraphs totally subjective, which takes it in large
part out of the realm of science. Yeah, voodoo science
is what they call it. And uh, all the proponents
(12:48):
will say that a well trained forensic psychophysiologists which is
the examiner, can get through all that to still get
a good result. They're like, yeah, they know all this stuff,
and if you're good, then you can factor that in
and still get a good result. So let's talk about
what the forensic psychophysiologist does. There's apparently I've seen anywhere
(13:10):
between five thousand and ten thousand of them in the
US at any given time, UM, and some of them
belong to professional organizations. I think probably maybe half or third,
depending on where you are on the on the estimate,
UM belonged to any number of professional organizations. Some have
(13:32):
no accreditation whatsoever, um, but are still able to open
up shops depending on the state there in. Some states
have zero laws about being a forensic psychophysiologist a k
A polygraph examiner. That's right, but there is also some
there are programs out there. Uh. The who wrote this article,
Kevin bondser I don't know. I think so he he
(13:54):
UM interviewed a guy who founded the Accidon Academy exit
Haunt as a manufacturer of polygraphs, and they founded this
academy as well, where um, you go through a certain
amount of training to become a forensic psychophysiologist. And he
actually interviewed that guy. Yeah, his name's Bobb Lee Lee. Uh,
(14:16):
and Lee says that if you come to their academy, UM,
you have to have a baccalaurea degree bachelor's right, or
you have to have at least five years investigative experience
and an associate's degree. Um, you have to take a
ten week course, and after you complete the ten week course,
you have to carry out twenty five polygraph examinations and
(14:39):
submit them to be reviewed. Uh. So these are like
real life ones. I guess you're working with your local
police department or whatever. Maybe you're already a cop UM
and you have to submit it to the Accident Academy
board for a review. And then once they're all reviewed
and everybody's all thumbs up, you are a life since
(15:00):
I guess. But you're not licensed because there's no licensing body. Um,
you are you graduate? I guess is is what they
call it. So that's as accredited as it gets. I guess.
And like you said, Um, proponents of polygraph testing say
that there, if you're a good FP, you're gonna be
(15:22):
able to structure everything correctly so that you can see
past somebody who's just who sweats a lot like you,
or who gets stressed out easily like me, Um, and
design your questions appropriately, and you're gonna be able to
to to figure out whether this person is deceptive or not.
So how how would you do that? Chuck? Well, we
(15:43):
should talk about the test itself. I guess. Uh, you're
gonna you're gonna go in and you're gonna get a
pretest before you get strapped up to anything. Could take
about an hour. This is just you and those the
only two people in the room. You're not surrounded by
folks like in the movies and stuff, although a movie
sometimes it's just two people, I guess. But the pretest
that you're just going to get an interview basically about
(16:06):
basically about why you're being investigated. Uh, they're also gonna
be profiling you and checking you out and just seeing
what kind of questions you respond to and what might
make you nervous, just so they'll be better informed about
how to properly question you once you're all strapped in
right and the pretest where you're just kind of hanging
out with them casually, the examiners also kind of getting
(16:28):
info out of you that you might not be aware of, like, um,
if you are uh, if you talk leisurely about your
favorite beer at one point and how you like it
a lot, and then later on it also comes up
that you have to drive a lot um, they might
come up with it. They might use that for a
control question, UM, which could be something like have you
(16:49):
ever driven under the influence of alcohol? And a control
question is something where you would have to admit guilt um,
and you may not want to, but it's such a
broad question that just about anybody is guilty of it,
like have you ever lied to somebody? Have you ever
um stolen anything? That kind of thing, So where if
you say no, they now have a baseline for what
(17:12):
it looks like when you lie. That they can make
a reasonable assumption that you have just lied. And any
of the data UM captured on the polygraph they're going
to use to analyze everything else off of. And that's
pretty much it. That's the test, and afterward you have
the post tests where they look at all the data
(17:33):
and chart out whether or not they think you're deceptive
and aware. Like on this question you were deceptive. On
this question you may have been deceptive. It's kind of
hard to tell. On this one you definitely were deceptive.
So so, and it's all in it's all in relation
to that control question, that baseline, right, So if you
if your deception, if you if on questions where I mean,
(17:56):
they're going to have to talk to the police as
well too and say what do you want to know
out of this person? So they'll design questions around that
as well. Um, so they may have a question like, um,
are you wearing a blue shirt? That may be question one,
it's irrelevant, right. Question two is, um, have you ever
lied to your boss? That's the control question, and then
question three is something like you know, did you steal
(18:19):
the cookie from the cookie jar? Like that's the one
that the cops want them to ask. They'll compare the
results of Q three against Q two and if they're
the same or you can't really tell, that's in UH
in that that's an UH inconclusive tests. So that's it.
I mean, like you said, that's that's polygraph. It's pretty easy,
(18:57):
it is. It's Uh, it's um jar ringly easy, considering
that it's used in legal cases a lot, right, Yes,
that's true. Um. People try to to battle the LDE
detector in various ways or a little tricks that the
Internet says works, like taking a sedative or putting any
perspirint on your fingers, which seems like they would make
(19:18):
you wash your hands, Uh, putting attack in your shoe,
and anytime you get asked a question, every single time
you stomp on the tack. And the idea is that
you're just gonna skew the tests so they all look
the same, so your body has the same reaction no
matter what's going on, like they I guess, if you
press on the tack, your physiological response could overwhelm any
(19:39):
response to the question. Right. Um, Like I said, there,
these these things are used in legal cases, but with caveats. Right.
If you undergo a polygraph, Uh, whether you fail or pass,
it doesn't really matter legally speaking, right, um, because of
(20:01):
unless you're in New Mexico. Yeah, this is the only
state that allows it just openly. Like if you take
a polygraph like, it's admissible in court yeah, every other state. Um.
Usually the both sides have to agree on it being
admitted or um. The judge has to say, yeah, we're
gonna admit this one, right, Yeah. And federally, the judge
decides whether or not they're going to admit it, right,
(20:24):
And I guess state judges kind of follow that federal
ruling of polygraphing. Yeah, And it's sort of a crapshoot
if a federal judge is gonna allow it or not.
There's no precedent really to where they say we have
to or we don't have to. Right. So, what are
the problems with this um? The problems with a polygraph
(20:47):
um or that it's subjective, Right, that's a big one.
But also because there because it's subjective, you can get
what are called false positives and false negatives. Yeah, and
you don't want that because then the test itself is
just not valid. Right. Uh. But I mean that a
lot of people use that as evidence that polygraph polygraphy
(21:09):
shouldn't be done at all, that it's not valid. False
positive and polygraph thing is when you find somebody who
is deemed deceptive but was telling the truth. False negative
is when somebody who wasn't telling the truth UM is
deemed truthful. Like Gary Ridgeway, the Green River killer. They
(21:30):
had him for a little while and gave him a
polygraph and he passed and they let him go and
he went and killed a bunch more women. All right,
that's right. I didn't know that. Actually, Yeah, there's also
the uh. You know, the federal government is the largest
uh consumer of these exams, and if you work for
the federal government, you've probably had one to get the job.
But you can't do that in the private sector thanks
(21:51):
to the Polygraph Protection Act Employee Polygraph Protection Act in
the late eighties, they said, you can't force your employees
to do this US. You can request it, but if
they don't want to do it, you can't fire them
because of it. You just can't do it, right, not
in private land, right unless you have a contract with
the government, and then that's not valid. But yeah, the
(22:14):
the federal government is the largest opponent to him in court,
but also the largest consumer. And imagine that, UM. And
there's been a lot of cases that shaped its admissibility
or not. But the polygraph it seems like it's kind
of honest way out. I wrote an article about UM
M R I being used as lie detectors, and that's
(22:35):
starting to kind of come into fashion the more we
start to understand, like how lies are born in the brain,
being able to see it and saying this is the
pattern that will happen. UM. If this person is lying
and then that pattern happens, they say, what, we know
you're lying. We just saw that live form in your brain.
That makes sense, yes, But at the same time, people
who understand MR eyes say, is way too early to
(22:59):
be doing that. And even if we can do it
with accuracy, there are a lot of moral and ethical
questions to it as well that we need to address.
First always uh and then penile plus demography. What's that? So?
Remember the the UM newmeographs that go around the chest
and the abdomen. Imagine one of those that goes around
(23:22):
the penis and it does the same thing. It the
text changes in contraction and girth. It's a perfect way
to put it UM and it's used to detect arousal.
They use it for UM sex offenders. It's under at
least as much attack as regular UM polygraphs. But I
(23:42):
wrote this blog post called UM using science to root
out late in homosexuality among homophobes. A study at U
g A used UH penile pleas plesismography UM to find
if anyone who they had deemed homophobic be came aroused
to inexposed to homosexual pornography. Yeah, it's it's one of
(24:06):
the better posts I've ever written. Cheese, all right, that's
our future. I guess peno pleathismography for everyone, everyone with
a penis at least and then chuck. Lastly, I want
to encourage everybody, if this has piqued your interest about
lie detectors, to go watch the shoe Court shoe store
(24:26):
job interview clip from Mr Show on YouTube. You remember
that one. It's very good weather friend Paula Thompkins and
he has a breakthrough. Was seeing that one? Yeah, yeah,
good old p f T yep. And that's it for
lie detectors, right, Yeah. I want to take a test.
If there's someone in the Atlanta area that administers these
and would be willing to give me a lie detector test,
(24:49):
I would love to do that, Okay, and I'll watch
yes UM as long as I can, you know, approve
the questions or not approve them. But I don't want
to be like rooted out as some miscreant. That's a
little late for that. Just keep it above board. UM.
If you want to know more about lie detectors and
(25:10):
play with some Lie detector flash animation, you can do
that by typing in lie detector on this in the
search bar on how stuff works dot com and UM,
that means it's time for listener mail. That's right, Josh.
This is from Brad and Brad. If you remember, we
had a list of suggestions from a listener not too
(25:31):
long ago that thought our podcast could be a lot
better if we changed a few things. Brad has some
suggestions of his own of how we can make the
podcast better. We should both have nicknames zazz up the
actual name like welcome to stuff you should Know with
j C and the Dingo, sit back while getting a
big helping of knowledge from Chucko and the Duck. I
(25:54):
second the suggestion to remove the personal anecdotes should be
moved to a separate podcast called the Josh and Chuck Memoirs.
Daily one hour podcasts can recount your lives from birth
to present, focusing on depressing stories that are marginally factual.
It's in development, Chuck, please your raise your voice one octave,
Josh lower yours one octave. What okay? So now this
(26:18):
is how I talk to the opening of the podcast
should be a description of what each of you ate
that day and the number of trips to the bathroom.
This allows the listener to keep track at home. Hedgehogs,
brain surgeons, arcades, and Bolivian politics are underrated, under sorry,
underrepresented on your podcast at least should be about these subjects.
(26:40):
Do not exclude listener mail. Instead, create a quieter audio
track reading the listener mail and overlay it on the
rest of the podcast. That way, listeners can hear both
the mail and the main content at the same time.
This is a pretty good idea. Why not set the
pod we literally driving people in Spain? If we did that,
why not set the podcast to a backdrop of tribal
(27:01):
drums and jungle animal noises would give it an exotic feel.
That's over the listener mail track, over the whole thing,
So that'd be three tracks deep. Yes, and it would
lead to suspense for the listener to wonder if you
will be eaten by jaguars? Uh. And it was clear
from the podcast on Mummies neither of you had ever
been mummified. Please refrain from explaining topics that you don't
(27:23):
have personal experience with. And then the final suggestion, just
retail episodes of this American Life that went that last
one went down like the Dave Glitterman top. Finally, so
that's Brad, Thanks brand. Those are all great ideas. Three
tracks all in one, streaming at once together listener mail
quietly to podcast and tribal drumming and jungle noises. Yes, um,
(27:48):
let's see. If you have access to a polygraph and
want to hook chuck up to it, let us know.
You can let us know on Facebook at facebook dot com,
slash stuff you Should Know, You can tweet to set
s y s k podcast, and you can send us
a regular old email at stuff podcast at how stuff
works dot com. Stuff you Should Know is a production
(28:12):
of iHeart Radio's How Stuff Works. For more podcasts for
my heart Radio, visit the iHeart Radio app, Apple Podcasts,
or wherever you listen to your favorite shows
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Chuck Bryant
Josh Clark
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