I don’t have the firmest grasp on the way a polygraph functions, but I’ve just had this thought a lot.
Could a polygraph help people uncover repressed memories? For example if a person suspects they were being harmed as a child, but can’t remember details, could a polygraph help them get more answers? Like by asking specific questions maybe related to what a person suspects happened and detecting how they respond.
Or, is a polygraph only useful to detect truth/a lie about things someone is certain about and remembers fully?
In: 0
Polygraph is designed to measure your nervous system’s response to being asked a question, or giving your answer. If you genuinely feel.your answer is truthful (or don’t recall it not being so) then the test will not say you are lying. In the same way if you can control your emotions and autonomic response very well, you can fool the test. It is actually very well documented that the test is not infallible.
No, a polygraph can’t be used to help someone recover lost memories. The techniques you described will more likely cause someone to invent a memory that never happened.
Most of what a polygraph does is tell the operator if you’re nervous. It’s primarily used by law enforcement to intimidate suspects.
No.
All a polygraph does is measure a set of physiological responses – like how fast you a breathing, what your pulse is, how sweaty your hands get, etc. The “science” behind a polygraph is that if you are lying, you are going to have an involuntary stress reaction, causing one of those responses to change. I say “science” because there is a host of evidence that polygraphs don’t work as lie detectors – people can get uncomfortable telling the truth and there are proven ways to trick the machine even when you are lying.
Even **if** the polygraph was 100% accurate in detecting lies (which it is **not**) it only works if the subject _knows_ they are lying, and thus has the involuntary response. It would not be capable of telling if someone was telling a lie they _thought_ was the truth, as they wouldn’t have the physiological reactions the machine can dectect.
A polygraph is an unreliable way to see if someone *knows* they are lying. If they are unintentionally telling a lie that would not be detected by the test.
It’s just measuring things like blood pressure, heart rate, etc. These things tend to change when we are lying. So if we do not know we are lying those things would not change.
Neither. Polygraphs are pop pseudoscience used by police to manipulate people. They are not admissible in court and are basically just stress-response sensors. Hence the incredibly unreliable nonsense of a high-stress interrogation where your life could massively be impacted or public humiliation on trash TV shows.
Extremely unlikely.
Most courts will not allow the admissions of polygraph tests because they are pretty much 50/50 at determining the truth. Meaning it’s random and doesn’t really work.
It can only test for the biological markers of you being nervous. Which *does* have a correlation with someone telling a lie. However, being hooked up to a machine and being asked questions will make you nervous as well.
>Or, is a polygraph only useful to detect truth/a lie about things someone is certain about and remembers fully?
It’s not even useful for that. They’re basically fake.
Polygraphs aren’t admissable as evidence because they don’t work. There’s no specific physical response that indicates lying.
The concept of repressed memories is controversial at best with most modern psychologists not believing that they even exist. It’s from Freudian psychoanalysis which is taken about as seriously as the four bodily humors and phlogiston these days.
This is kind of like speculating on using love potion to drive off a succubus. Neither of those are things.
The polygraph isn’t even an effective lie detector. All it detects is how much stress the subject is under. If you feel no stress from lying then the polygraph will detect nothing.
Although it is possible that a polygraph could detect if you’re stressed out over a certain memory or not. If you had a traumatic event and repressed it you might have a stress response when trying to remember it. This would detect that there is a repressed memory but wouldn’t tell you what it was.
A polygraph is only useful to trick a suspect into incriminating themself or building a convincing probable cause argument. They don’t detect lies, they detect bodily stress responses, and one of the most stressful situations you can be in is defending your own innocence against someone who’s already decided that you’re guilty. The results of a polygraph test are not admissible in US courts as evidence of guilt or innocence for this reason.
I know that doesn’t answer your question but police love to use the fact that polygraph tests are so poorly understood to do things that moral or ethically-bound people might consider heinous. Don’t ever let the police talk you into taking a polygraph test even if you’re innocent and they tell you it could clear you, or you’re guilty and you think you can trick it.
Latest Answers