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what about those that that have been trained to lie you know that this is this is they know
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how to do this they know how to lie in an interrogation is that possible are we able to
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to train people to lie oh people lie all the time i don't know if you have to be trained i
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think people learn as they grow up there's all kinds of lies people can tell right you can tell lies about the
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past the future yourself other people you can lie for fun you can lie to not be punished you can lie because it's
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your job if you're a professional working undercover you have to lie you can tell lies about what you did or what
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you will do those are all different kinds of lies so in the context of when people are being
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questioned by the police there's a number of ways in which a person could look if they are deceptive could look
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absolutely normal whereas a truthful person might actually be frightened of the police and they
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ironically would look deceptive there's this thought that if you want to know if someone is lying you should be
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able to tell by just looking at them that people give off signals of dishonesty this is huge in tv shows like
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sherlock and lie to me plastic one-sided shrug translation i have absolutely no confidence what i just said the body
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contradicts the words he's lying it feels so compelling that you should be able to recognize you know fear disgust
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anger uh sadness and that these are universal expressions and i think that it's true that around the planet by and
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large many emotions are expressed similarly on by by the facial muscles not entirely but similarly what's really
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i think more questionable scientifically is whether or not these expressions or micro facial
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expressions these quick flashes of human emotions on your face are actually signals of lying
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so if your body doesn't matter the way we've thought it has for so long and what does
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i'm phoebe judge and this is criminal [Music] for 20 years andy morgan has been studying human memory and deception he's
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worked with the fbi cia the military law enforcement groups and it goes without saying that all those people morgan
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worked with they really like to know when someone's lying to them they will do some crazy expensive exhaustive
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things to find out if someone's lying to them but what we're learning now is that a
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lot of those things they've been trying they just don't work we've been looking for physiological
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clues since the 1920s with the invention of the lie detector this is the read polygraph
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a lie detector in the past 20 years an estimated 200 000 persons have staked their futures
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many of them their lives on this machine the polygraph as you know is a device that
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records how fast you're breathing sort of your respiration rate and how much your chest is moving they put tubes
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around your chest and the general belief in law enforcement and within the polygraph community for years has been
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rooted in the idea that we call the fear and alarm hypothesis that variations in
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blood pressure and pulse rate are present during and after the act of lying that
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telling a lie is threatening in some way and that threat to you will trigger a difference a shift the conscious act
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of lying creates an emotional disturbance and and cause your blood pressure to rise or
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your skin conductance to go up or your respiration rate to change like holding your breath or maybe breathing more
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rapidly now it may not shock you that the polygraph isn't a perfect tool but we were actually surprised to learn just
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how inaccurate the machine is we actually know the polygraph in the way it is mainly used
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is not better than chance at detecting deception maybe slightly at 52 52 53 you could literally flip a coin and be
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just as accurate as the polygraph at detecting a lie but the idea that your body gives you away is still very much
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alive it's still being used in police departments all over the country cops are trained to read body language
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some investigators claim they can watch an interrogation with a sound off and know if someone's lying
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but what andy morgan says is that when put to the test people aren't any better at sensing a lie than chance
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and if that's true that we can't see a lie that we can't hear a lie or smell a lie or physically sense in any way when
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someone's playing us then what do we do [Music] about a decade ago morgan and some
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colleagues decided to test a different technique they started interviewing people from all over the world about
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1200 of them so ranging from white brits to chinese east indians lebanese jordanians
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moroccans sudanese afghans iraqis vietnamese russians my colleagues and i have tried to study
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people inside and outside the united states and we've mainly used a particular technique
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called cognitive interviewing cognitive interviewing is based on the premise that memory doesn't work like a video
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camera there are sights and sounds and smells stored deep in your brain that can all be recalled if pushed hard
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enough so every time morgan sat down to interview an american or jordanian some of them would be lying and others would
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be telling the truth and he would ask them to do something pretty simple to tell us a story about what they've been
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doing the most memorable concert that i've been to it's not the best it's the most
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memorable so obviously this isn't actually tape for morgan's research we just put some of our friends to the test
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was yay sayer about a year ago i went to a foo fighters concert in 2005 for the in your honor tour and then say
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so if you imagine for a minute that i was there with you what would i have seen if i'd been there with you the
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entire time they had the lights programmed with the music and so the mirrors really like reflected the
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light and so there was like it would form shapes then we say when they're done so i think i'm getting a better picture
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in my head so imagine from a moment i was with you but this time i was blind and i could only listen what would i
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have heard during that time so it's more of a shuffling of like rubber against pavement there go down metal steps go
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down to the car all car doors open you know depending on the contacts you might say what would i have smelled there was
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this this girl that was standing next to me who was in his sweater dress who did not wear deodorant and then we
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say starting with the very last thing that happened um what do you remember happening right before that uh
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leave dorm right before that go walk backwards to car right before that get in car come
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back to dorm kind of having them just walk us backwards through their memory crunching guitars and awesome drum stuff
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what's been found over the years in many studies of cognitive interviewing is that using those
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mnemonic prompts those those sensory prompts what you would have seen heard smelled thought touched or tasted
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they trigger more memory recall you get more detail the picture becomes much more rich and complex without suggesting
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anything specific to the person you're interviewing but here's where things get interesting
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turns out if you're telling a lie a made-up story even one that's well rehearsed
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you can't complete this interview not without giving yourself away if you tell a very simple lie there's not much work
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to go i don't know and you have nothing to say kids do that all the time but if you're telling uh if you're telling a
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story that's reasonably complicated and supposed to be believable because if i'm
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lying to you my goal is to sell you the story i'm telling you and then to leave before you figure out it's not true
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or not to bring up anything that might lead you to suspect that it's not true i'm trying to tell my story and stick to
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it we find that liars are often worried that if they're inconsistent they will be thought to be lying so what they do
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is they tell you a story so if i say tell me everything that happened they might tell me quite a wonderful story i
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went to see florence in the machine it was like in the spring but then when i say
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so let's go back to the beginning so imagine i was with you what would i have seen you know heard thought smell touch
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tasted or walk through it backwards the overall result is they have very little to say do you remember the car
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ride home uh not really they will say things like well pretty much just like i told you
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before and they will repeat uh very closely the same thing they've already told me so that i'm not learning
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anything new over time the thing is i don't even really remember it's sort of like comparing a digital photograph of
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your house with the tree in the front yard and a child's picture of it where there's a house and there's a tree and
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there's clouds and there's birds but there's not a lot of detail and what we tend to do when people tell us lies as i
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think we fill in that we fill in the blanks and that morgan says is where the problem lies we fill in the blanks
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because of course we want to believe people so andy morgan's challenge was to find a way to take these interviews and
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analyze them without filling in the blanks to do this he had to put a little distance between himself and the
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interesting person telling the story the way we've analyzed that in most of our studies is we record the interviews and
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we do a transcript and we let the computer just count the number of words that comes out of a person's mouth in
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the interview and the number of unique words that comes out of their mouth that so if you think about the phrase
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one small step for man one giant leap for mankind there are ten words but you've used one
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and four twice so there's only eight unique words as you're thinking harder about monitoring what you're saying it
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has the side effect of reducing the richness of what you have to say and shortens the
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thing that you have to say all the computer is doing is counting those two variables and
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when we sort people based on those two variables response length and unique word count
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the computer's right typically 80 to 85 percent of the time [Music] whereas our professional raiders whether
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they come from homeland security or the fbi or the dia or other intelligence groups or law enforcement
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our human raiders are rarely better than 54 correct it's kind of a crazy idea that someone
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with a transcript and a tally sheet could tell us whether or not what we're remembering is accurate while someone
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with decades of fbi interrogation training could be flying blind and this idea could have all sorts of
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huge implications think about a jury a jury is just a bunch of people trying to figure out who to believe
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but people according to andy morgan are terrible at figuring out who to believe isn't it possible that a juror with a
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transcript of the trial who's never laid eyes on the accused might actually do a
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better job at figuring out who's lying who to trust for andy morgan's part he's glad our
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bodies aren't the end-all be-all it's reassuring to know that although there's so many books on nonverbal behavior and
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people say 90 of communication is nonverbal based on the science i think that the best way to sort out
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the truth is to listen to what people have to say and to know that maybe our fate won't
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hang on sweaty palms or pounding heart that our words really do matter [Music] thanks to andy morgan who's a forensic
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psychologist at yale and just in case you were curious during his interview with us he used more than 7200 words and
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enough unique words to make us trust he wasn't lying the show is produced by lauren spohr
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eric metal and me i'm phoebe judge and this is criminal you