Are Polygraphs Accurate? | Does Phil McGraw Have Magic Lie Detectors?

welcome to my scientifically informed insider look at mental health topics if you find this video to be interesting or helpful please like it and subscribe to my channel this is dr. grande today I have several questions about polygraphs these so-called lie-detector tests how did they function what are the counter measures that may be used against them are they accurate I've had a number of questions specifically about phil mcgraw usage of polygraphs on his show we also see this surprising statement on his website about polygraphs that I'll talk about in this video so first I'll start with how does a polygraph work so the idea behind the polygraph is that an examiner as they're called the person operating the polygraph lies to the subject the subject is the person who is ostensibly being tested so right away here at the beginning of pie graph usage we see that there is at least one person lying the examiner the examiner tells a series of lies that are necessary for the interrogation to have any chance of being successful as the examiner gets ready to tell these lies they start by saying something true they explain what the Machine measures it's designed to record respiration sweat gland activity and blood pressure so this part is true the examiner fails to mention that none of these reactions are uniquely tied to deception meaning changes in these activities could mean anxiety or fear unrelated to deception the examiner instead completely misrepresents the machines capabilities suggesting that the machine is so advanced it can detect even small lies for example if someone lies to their spouse by saying their spouse looks good in clothes that don't make them look good right so even this type of fairly common lie can be detected by the incredibly powerful polygraph this deception by the examiner is designed to make the subject a freight without the subject being afraid the polygraph cannot perform any better than chance so really the test is entirely based on fear after this the examiner performs what's referred to as the stimulation or acquaintance test the examiner indicates that they need to adjust the instrument to make sure that is able to detect a lie to that specific subject who is being tested so here the examiner really just uses a trick to convince the subject that the machine allows the examiner to read the subjects mind for example the examiner might ask the subject to write down a number between 1 and 10 and then to answer no each time the examiner asks about a number so did you write down the number 1 did you write down the number 2 at the end of this face the subject really believes the polygraph works and a holder version of this test that's not used anymore I think illustrates the point a little more clearly the examiner would have a deck of cards but all the cards were the same right so say the card was an 8 of clubs so the subject would pick one of these cards and then the examiner would ask a series of questions that narrow down what card it was so these are all yes/no questions but through a series of questions the examiner could actually again get to that precise card so at the end the examiner would say yes the card is made of clubs and the subject would be amazed they would think wow this polygraph must really work right so this pretest trick is critical to the polygraph again functioning at any level of accuracy next we see a pretest interview this is different than the acquaintance test this is used when the examiner is deploying the cqt method this is the comparison question technique sometimes called the control question technique there are three types of questions on these tests we have irrelevant the comparison or control I'll refer to this as the comparison and the relevant so the irrelevant would be something like the subjects name is your name mr. Smith yes or no the comparison question is designed to trick the subject into lying so the pretest interview is really designed to create these comparison questions then we have the relevant questions and these are the ones that are connected to the reason for the interview like asking the subject if they have committed fraud theft or ever used illegal substances something like that so during this pretest interview the examiner needs to formulate these comparison questions because they need the subject to lie during the actual interview so in the pretest interview the examiner might ask the subject a question like have you ever lied so the subject might indicate they've told small lies to family members now the examiner will adjust the question based on that information for the actual test so the examiner might say something like besides the lie you already told me about have you ever lied to your family members right so they're really trying to create this situation where they can get the subject to tell a lie the examiner will also make it clear that an affirmative response to that question would be unacceptable for example if it's a pre-employment polygraph they might say that the agency would never hire somebody who lied to their family members regardless of the type of lie they told so why is it so important that the examiner tricked the subject no lying because the only two questions that matter on the test are the comparison and the relevant so the irrelevant question is irrelevant as it turns out many people believe that the irrelevant questions are scored but they're not they're not part of the scoring in the test the examiner compares the reaction to lying on the comparison questions to the reaction by answering the relevant questions from this there are three possibilities the physiological reactions to the comparison and relevant questions are similar so the examiner would say this test is inconclusive the reaction to the comparison questions is greater than the relevant questions this would suggest the subject is being truthful and the reaction to the comparison questions is less than the relevant here this in theory indicates deception outside the fact that there is no physiological response to deception another obvious flaw here is that somebody could be answering truthfully to the comparison questions now instead of comparison questions designed to trick the subject some examiner's use comparison questions where the individual is told to lie this is actually not part of the comparison question technique method it is referred to instead as the directed lie control test if the examiner suspects the subject of lying they often do a post-test interview here they essentially try to trick the subject into confessing using simple tactics we see several here I'll just go over some of them the examiner could use a false accusation so they might say it's not a matter of if you did it or didn't do it it's a matter of how much more trouble do you want to get into they could say something like I would respect you more if you would just tell the truth so trying to factor their relationship with the subject into the interview they might say you can help yourself a lot by being truthful right now so it pressure tactic they could say it's not lying to me that was detected it's you lying to yourself that was detected right so that's a favorite among examiner's and we see if the subject pushes back about the validity of the test which of course makes a lot of sense if they were telling the truth the examiner might say oh okay now let's blame the test right so they can get kind of sarcastic and try to flip things back on the subject so now moving to the next question our counter measures successful against polygraphs so I'm not going to go into detail about a lot of counter measures but I'll cover a few here that have been shown to be successful in general now counter measures are only focused on the response being measured so we can look at the three items I talked about before starting with respiration here a counter measure would be somebody maintaining a steady breathing rate then changing it when a comparison question is asked for example hesitating inhaling and exhaling more slowly inhaling at the same rate but exhaling more slowly or taking a deep breath we also see counter measures for sweat gland activity and blood pressure a popular one is picking a number and counting backwards by a certain number right so somebody might think of the number seven hundred and then start counting back by 13 right this creates a cognitive load this is hard to do and it can increase the response we also see somebody could calculate the cube of a number right so they can think of the number 3 and then 3 times 3 would be 9 9 times 3 be 27 right so again calculating the cube of 3 that would create a cognitive load and there's also the tactic of causing stress by imagining oneself to fall off of a building so moving on to the next question are polygraphs accurate so in seeing how the polygraph functions it becomes clear why it's not valid for detecting lies but the polygraph can be part of an effective scheme to elicit somebody telling the truth right so a confession or something like that somebody revealing something that the examiner wants them to reveal the pie graph itself is nothing more than a machine used by someone conducting an interrogation usually some type of law-enforcement officer is the person operating the polygraph the polygraph is more or less a prop as the information it records is not exclusively relevant to deception as I talked about before when this machine is combined with an interrogation strategy it does a better job than chance of detecting a lie depending on the research the accuracy is estimated somewhere around 60 to 80 percent when countermeasures are deployed by the subject who's being examined the accuracy is dramatically reduced now the word accuracy is kind of tricky here I'll talk about how this relates to polygraphs in a moment why it's not really the best term the challenge with the polygraph is that it measures physiological responses with the idea that there's some sort of physiological response pattern to deception when of course there's not if one person's lying their reaction might be different than another person who's lying we see a lot of variability in this area now on top of this fact the interpretations of the pie graph chart are imprecise to say the least confirmation bias is a tremendous problem with these so called examiners the examiners are trained to find lies not to find the truth right so they decide in advance who's lying and who's being honest even several diehard polygraph supporters have acknowledged this problem other available methods of lie detection like interviewing techniques have been found to be equally as effective as the comparison control technique so this brings me to the question around Phil McGraw's use of polygraphs on his show is this a good idea should he be doing this do his polygraph somehow work are they like magic polygraphs on phil mcgraw website there's a statement by a man named Jamie skeeters he is the president of the California Association of polygraph examiner's this is a real Association I didn't make this up the statement defense polygraph use on the dr. Phil show mr. skeeters claims that research has proven the polygraph is accurate more than 90% of the time he also says that research indicates that there is no such thing as a false positive or false negative result again this is directly on phil mcgraw website it's not hidden it's right there in plain view so I can understand why people were alarmed by this how could a test be wrong 10% of the time but not have a false positive or a false negative that's literally the definition of wrong in this instance the only result outside of those would be a true positive or a true negative otherwise known as accurate results so I guess we're supposed to believe that the test is 90% accurate and the remaining 10% is accurate as well this kind of reasoning really kissed me a headache other than the obvious problems with mr. skeeters statement another issue is that it really shows of lack of understanding of the receiver operator characteristic curve otherwise known as the ROC curve if we think about a polygraph there are two rates that are important the rate of correctly classifying deceptive individuals this is referred to as sensitivity and the rate of correctly classifying truthful individuals this is called specificity the area under the ROC curve cannot actually be directly translated into an accuracy rate the only thing that really matters is the sensitivity and the specificity now the 90% accuracy statistic is solidly refuted by credible research but if one were to use this accuracy statistic as meaning 90% sensitivity the corresponding false positive rate would be 27% so 27 percent of innocent subjects would be categorized as guilty and of course this is clearly unacceptable so what's the bottom line with polygraphs there is no scientific reason that they should be used for any purpose whatsoever much less to manipulate guests on an entertainment show so if polygraphs are pseudo scientific nonsense why do so many agencies use them are all polygraph operators delusional or misinformed I don't think they are I think much of the time they know exactly what they're doing they believe in their interrogation techniques and they need that machine so they can more easily deceive people they believe falsely accusing some innocent people is worth it in order to uncover the guilty so to them the ends justify the means when people like Phil McGraw put this machine on national television and say that it's valid they propagate dangerous misinformation I know whenever I talk about topics like polygraphs there will be a variety of opinions please put any opinions and thoughts in the comment section they always generate an interesting dialogue as always I hope you found my analysis of this topic to be interesting thanks for watching

Channel: Dr. Todd Grande

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Keywords: polygraph, lie detector test, Phil McGraw, Dr. Phil, narcissistic personality disorder, sociopathy, grandiose narcissism, vulnerable narcissism, covert narcissism, shame, anger, aggression, hypersensitivity, anxious, depressed, socially awkward, neurotic, shy, manipulative, blame-shifting, gaslighting, self-esteem, manipulation, arrogance, self-centeredness, jealousy, special, unique, fantasy, entitlement, grandiosity, requires admiration, lack of empathy

Id: I-q5vdQSbG8

Length: 14min 59sec (899 seconds)

Published: Wed May 13 2020