Do Polygraph tests really detect lies?

"The accuracy (i.e., validity) of polygraph testing has long been controversial. An underlying problem is theoretical: There is no evidence that any pattern of physiological reactions is unique to deception. An honest person may be nervous when answering truthfully and a dishonest person may be non-anxious. Also, there are few good studies that validate the ability of polygraph procedures to detect deception. As Dr. Saxe and Israeli psychologist Gershon Ben-Shahar (1999) note, "it may, in fact, be impossible to conduct a proper validity study." In real-world situations, it's very difficult to know what the truth is.
Evidence indicates that strategies used to "beat" polygraph examinations, so-called countermeasures, may be effective. Countermeasures include simple physical movements, psychological interventions (e.g., manipulating subjects' beliefs about the test), and the use of pharmacological agents that alter arousal patterns."

http://www.apa.org/research/action/polygraph.aspx

Even assuming the polygraph operator is legitimate and qualified, all it takes to pass a polygraph test is to 1.) take a pill and/or 2.) rehearse for it.

It is notable that for the so-called polygraph test the after-the-hearing-ended public accuser of Kavanaugh - a partisan never-Trump Democrat college professor claiming an event over 3 decades ago with no evidence whatsoever is that the polygraph operator was selected by a lawyer who specializes in suing men for sexual harassment or abuse - a lucrative new area of law as substantial men will pay big money to keep the accusation secret as the mere accusation can destroy him. Add announcing "she passed a polygraph" to be publicly divulges makes it the perfect shakedown.

What the woman drug tested at the same time before the test? If not, the test is completely worthless. Was she told the test questions before hand? If so, the test is completely worthless.

There is no "truth organ" in the human body. A police union (FOP) lawyer I know said of polygraph tests "they might as well read chicken blood and bones in a teacup, a magic 8 ball or use tarot cards."

The American Psychiatrists Association claims they are worthless, Congress outlawed their use and many circumstances and exactly no one claims they are fully accurate, even the Association of polygraph operators, nor is there even a standard way to do a polygraph test.

[h=1]Lie detectors: Why they don't work, and why police use them anyway[/h]http://www.apa.org/research/action/polygraph.aspx

joko104 said:

"The accuracy (i.e., validity) of polygraph testing has long been controversial. An underlying problem is theoretical: There is no evidence that any pattern of physiological reactions is unique to deception. An honest person may be nervous when answering truthfully and a dishonest person may be non-anxious. Also, there are few good studies that validate the ability of polygraph procedures to detect deception. As Dr. Saxe and Israeli psychologist Gershon Ben-Shahar (1999) note, "it may, in fact, be impossible to conduct a proper validity study." In real-world situations, it's very difficult to know what the truth is.
Evidence indicates that strategies used to "beat" polygraph examinations, so-called countermeasures, may be effective. Countermeasures include simple physical movements, psychological interventions (e.g., manipulating subjects' beliefs about the test), and the use of pharmacological agents that alter arousal patterns."

http://www.apa.org/research/action/polygraph.aspx

Even assuming the polygraph operator is legitimate and qualified, all it takes to pass a polygraph test is to 1.) take a pill and/or 2.) rehearse for it.

It is notable that for the so-called polygraph test the after-the-hearing-ended public accuser of Kavanaugh - a partisan never-Trump Democrat college professor claiming an event over 3 decades ago with no evidence whatsoever is that the polygraph operator was selected by a lawyer who specializes in suing men for sexual harassment or abuse - a lucrative new area of law as substantial men will pay big money to keep the accusation secret as the mere accusation can destroy him. Add announcing "she passed a polygraph" to be publicly divulges makes it the perfect shakedown.

What the woman drug tested at the same time before the test? If not, the test is completely worthless. Was she told the test questions before hand? If so, the test is completely worthless.

There is no "truth organ" in the human body. A lawyer I know said of polygraph tests "they might as well read chicken blood and bones in a teacup, a magic 8 ball or use tarot cards."

[h=1]Lie detectors: Why they don't work, and why police use them anyway[/h]http://www.apa.org/research/action/polygraph.aspx

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Polygraphs are ****.

I think they are bogus. Actual polygraph testers love to say they are so good at reading the machine... but I don't buy it.

Hopefully I never have to use one lol... because I feel like I know the exact questions that would matter.... and I would immediately start internally freaking out no matter if I did something or not lol.... just because I know that is the question that is the big deal...

I picked other. From what I under a lie detector works by measuring physical reactions someone's body makes when they are asked certain questions. Those reactions don't necessarily prove someone is lying or telling the truth. Those physical changes might mean someone is nervous or feeling pressured . It might in some people and not in others. Its probably why lie detectors are not admissible as evidence in many states.

Other - a polygraph shows a correlation of subject matter (questions asked) to physiological reactions to them. If you are 'nervous' about a subject (say a suicide or alcoholism of a family member or close friend) then a question about those subjects (topics?) may cause you to show physiological reaction to them. It does not mean that you lied about a specific question on that topic - it only means that you are sensitive to questions related to that topic.

Went with "IDK/Other" for one reason only, what a lie detector is really looking for.

No matter if by polygraph or observation the whole idea behind lie detection is the premise that someone telling the truth will remain calm. Where things get messy is determining the opposite of calm with either excitement or nervous excitement, and the difference between those two is the idea of what a lie detector is revealing or not. That happens to be the idea behind the "control questions" as a means for the polygraph and operator to know the difference.

Our question is does the premise always hold true, and for the most part the answer is no.

It is very possible to remain calm during control questions and become nervous about the real questions even when telling the truth, it is also very possible to be just as nervous during the control questions as any other question. If anything what the polygraph is revealing is factors that make someone nervous, but that does not always mean truth and lying. This is made worse by a small percentage of the population that has enough physical and psychological control to manipulate what a polygraph is looking for.

There is an association, American Polygraph Association, that claims 90%+ success rate then we have the American Psychological Association that puts the numbers much lower, each using various statistics to back up their assertions. Like, those failing eventually admitting to the crime. Or, those determined to have failed the test and ended up innocent. Because of all the factors that make these stats messy themselves we have no real way to show polygraphs are successful enough.

So, you end up with "Other" as they may help but cannot be the sole means to determine lying or not.

The Supreme Court has already gotten into the middle of this restricting their use in criminal proceedings. Defense cannot use them alone to prove innocence, prosecution cannot use them to de facto a confession, etc. Employers cannot use them to recruit "honest" employees. The government can use them for various positions employed by the government or military, but even then it is not across the board.

Because polygraphs are not conclusive they tend to pit the person taking the test against the examiner, not always neutral and that clouds the results even if they were more effective by stats.

Honestly, polygraphs are only as effective as the operators make it. We all understand the basic concept of polygraphs and how they operate, someone is asked a question and if the person in question has a subtle, physical reaction to the question it means they are reflexively asking the question. However, you can get the same kind of physical responses if the operator speaks threateningly or accuses the suspect out right that can generate "false positives."

So at best, a Polygraph can at best support evidence already provided in court.

Polygraph tests are informative as supplemental evidence. They cannot be considered sufficient as smoking guns, in and of themselves.

They are only used to prove guilt.

And they are not used in court because there are too many variables. People who stutter are all over the map as are people who's first language is not English as their emotions don't reflect accurately.

ttwtt78640 said:

Other - a polygraph shows a correlation of subject matter (questions asked) to physiological reactions to them. If you are 'nervous' about a subject (say a suicide or alcoholism of a family member or close friend) then a question about those subjects (topics?) may cause you to show physiological reaction to them. It does not mean that you lied about a specific question on that topic - it only means that you are sensitive to questions related to that topic.

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Ill likely never have occasion to like a post of your again so I liked thgis one while I had the chance.

There is no "controversy." Polygraphs cannot detect lies, period.

Law enforcement and other entities just use them to rattle interrogation subjects. Even if you intellectually know that polygraphs are not lie detectors, it can still be disconcerting to be hooked up to one, and barraged with questions. Some people just can't handle it and melt down.

That said, taking a polygraph test doesn't mean you are a liar. It doesn't really mean anything, except that "you took a polygraph."

Passing the test gives reasonable doubt to a jury. Failing the test pushes the general public to believe they are guilty. Refusing to take the test, makes you look guilty to the general public.

No, polygraph tests are not scientifically accurate. They generally can give LEO a good idea of whether or not a person is telling the truth based on increased heart rate, increased breathing, sweating, etc, but because they are easily bypassed (by drugs, breathing techniques, etc), they aren't really allowed in court.

Atheist 2020 said:

Passing the test gives reasonable doubt to a jury. Failing the test pushes the general public to believe they are guilty. Refusing to take the test, makes you look guilty to the general public.

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all true which is why we need to get rid of the test completely

Superfly said:

No, polygraph tests are not scientifically accurate. They generally can give LEO a good idea of whether or not a person is telling the truth based on increased heart rate, increased breathing, sweating, etc, but because they are easily bypassed (by drugs, breathing techniques, etc), they aren't really allowed in court.

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They are most valuable in coercing an innocent person into saying things that they would not ordinarily say that make them look guilty.

I would advise a truly honest person to never take one.

Visbek said:

There is no "controversy." Polygraphs cannot detect lies, period.

Law enforcement and other entities just use them to rattle interrogation subjects. Even if you intellectually know that polygraphs are not lie detectors, it can still be disconcerting to be hooked up to one, and barraged with questions. Some people just can't handle it and melt down.

That said, taking a polygraph test doesn't mean you are a liar. It doesn't really mean anything, except that "you took a polygraph."

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exactly

joko104 said:

The American Psychiatrists Association claims they are worthless, Congress outlawed their use and many circumstances and exactly no one claims they are fully accurate, even the Association of polygraph operators, nor is there even a standard way to do a polygraph test.

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That's nonsense. While I agree that they should not be used as proof in a court of law someone who knows what they're doing can very reliably determine if someone is lying. Sure you need to recognize if the person is on drugs. And you need to ask a lot of questions to make sure nobody can fully prepare for them, but they are very accurate more often than not.

Mythbusters actually did a really good special on it where they tested out countless ways to try and fool a polygraph. Nothing worked reliably. The professional polygraph operator got them every single solitary time.

CMPancake said:

Honestly, polygraphs are only as effective as the operators make it. We all understand the basic concept of polygraphs and how they operate, someone is asked a question and if the person in question has a subtle, physical reaction to the question it means they are reflexively asking the question. However, you can get the same kind of physical responses if the operator speaks threateningly or accuses the suspect out right that can generate "false positives."

So at best, a Polygraph can at best support evidence already provided in court.

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Exactly, I know that from personal experience. I was required to take one for the work I going to do, a health question came up that did no apply to me but I immediately thought of a family member who was affected and that triggered a blip. I saw it on the graph as it happened and after the session I referred back to it with the interrogator and told him the background. He said thanks, I was going to question you on that. So, I know for a fact a random thought that triggers emotion can create a false positive.

Atheist 2020 said:

Passing the test gives reasonable doubt to a jury. Failing the test pushes the general public to believe they are guilty. Refusing to take the test, makes you look guilty to the general public.

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Generally speaking, polygraphs are not admissible in court.

It might help in the court of public opinion, as a lot of people still don't understand that polygraphs are not accurate. However, it won't help you with a jury.

MrWonka said:

That's nonsense. While I agree that they should not be used as proof in a court of law someone who knows what they're doing can very reliably determine if someone is lying.

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No, they can't. Polygraphs simply are not accurate. People do not have consistent unconscious physical reactions to lies.

Mythbusters actually did a really good special on it where they tested out countless ways to try and fool a polygraph. Nothing worked reliably. The professional polygraph operator got them every single solitary time.

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The Mythbusters are usually pretty good, but not good enough to refute decades of existing research which show that polygraphs are not reliable.

Polygraphs detect physiological responses that correlate with deception at better than random rates. Coupled with a trained interrogator the results of a polygraph are more likely than not to be accurate among the general public.

“More likely than not” doesn’t mean overwhelmingly so, mind you.

Visbek said:

No, they can't. Polygraphs simply are not accurate. People do not have consistent unconscious physical reactions to lies.

The Mythbusters are usually pretty good, but not good enough to refute decades of existing research which show that polygraphs are not reliable.

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Yes, they actually do, and the experiments they performed were pretty conclusive. No method may be perfect, but many are incredibly reliable. There are all kinds of tests which are used to determine all kinds of things about you. Almost all of them have at least some kind of error rate. A breathalyzer will overestimate your BAC if you've had a drink very recently. Even though that drink probably hasn't hit your system yet.

This is why virtually every scientific experiment needs to be duplicated numerous times before the results will be completely accepted. There are all kinds of factors that can throw of the results of any one experiment, but over time the factors become indisputable.

Visbek said:

Generally speaking, polygraphs are not admissible in court.

It might help in the court of public opinion, as a lot of people still don't understand that polygraphs are not accurate. However, it won't help you with a jury.

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The goal of a defender is to raise reasonable doubt, and passing the test does raise reasonable doubt. My grand-aunt was murdered and we believed it was her husband. He passed the test and left the state. Out of sight, out of mind, passed the test -- the case was closed without anyone else suspected of killing her.

MrWonka said:

Yes, they actually do, and the experiments they performed were pretty conclusive.

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It was a sample of 3 people, and the operator had a fake PhD who knew they were going to try and lie. As a reminder, the Mythbusters may love science, but ultimately they are entertainers, stunt men and movie fabricators, not psychology researchers who engaged in double-blind studies or reported the results of decades of research.

No method may be perfect, but many are incredibly reliable.

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They really aren't. Lots of research shows that they are not much better than chance, and that includes false positives (i.e. registering true statements as lies).

There are all kinds of tests which are used to determine all kinds of things about you. Almost all of them have at least some kind of error rate. A breathalyzer will overestimate your BAC if you've had a drink very recently.

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Actually, that is only if you literally took a sip right before the test. On a properly functioning breathalyzer, the error of margin is very small. Defense attorneys may want you to believe otherwise, but unless you are right on the line, you're probably not going to get very far

This is why virtually every scientific experiment needs to be duplicated numerous times before the results will be completely accepted. There are all kinds of factors that can throw of the results of any one experiment, but over time the factors become indisputable.

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Yes, and the research on polygraphs has shown over time that they are not reliable. To wit:

Almost a century of research in scientific psychology and physiology provides little basis for the expectation that a polygraph test could have extremely high accuracy. Although psychological states often associated with deception (e.g., fear of being judged deceptive) do tend to affect the physiological responses that the polygraph measures, these same states can arise in the absence of deception. Moreover, many other psychological and physiological factors (e.g., anxiety about being tested) also affect those responses. Such phenomena make polygraph testing intrinsically susceptible to producing erroneous results. This inherent ambiguity of the physiological measures used in the polygraph suggests that further investments in improving polygraph technique and interpretation will bring only modest improvements in accuracy....

Notwithstanding the limitations of the quality of the empirical research and the limited ability to generalize to real-world settings, we conclude that in populations of examinees such as those represented in the polygraph research literature, untrained in countermeasures, specific-incident polygraph tests can discriminate lying from truth telling at rates well above chance, though well below perfection. Because the studies of acceptable quality all focus on specific incidents, generalization from them to uses for screening is not justified....
National Academies of Science and Engineering 2002 report, https://www.nap.edu/read/10420/chapter/2#6

Further, empirical studies fail to demonstrate effectiveness; countermeasures can foil the results; the tests can produce too many false positives to make it reliable.

Again, polygraphs are not admissible in courts in most states. This wasn't an arbitrary decision, it's because they are nowhere near accurate enough to qualify as any sort of genuine "lie detector." (There is also quite a bit of irony in the people who sell and operate polygraph services failing to be honest about the limitations...)

The only real use of a polygraph is to compel someone to answer questions. That's it.

Atheist 2020 said:

The goal of a defender is to raise reasonable doubt, and passing the test does raise reasonable doubt. My grand-aunt was murdered and we believed it was her husband. He passed the test and left the state. Out of sight, out of mind, passed the test -- the case was closed without anyone else suspected of killing her.

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Uh... Yeah, that's not how it works.

I can't possibly address a case for which none of us have, or can possibly gain, reliable information. What I can say is that "reasonable doubt" doesn't apply to investigations, it only applies to juries during an actual trial.

Police like polygraphs, not because they work, but because it lets them ask a suspect tons of questions, and rattles the suspect. Again, polygraphs are not admissible in court, so they don't contribute to any evaluation by a jury.