Let's say that a method of lie detection was created that was 99.99% accurate, portable, and cheap. It is also very generally applicable, and there is no known method to fool it.

Now, it is ubiquitous in society. Employers regularly use lie detectors to confirm that employees have not stolen or otherwise defrauded the company. Schools use lie detectors to confirm that students are not cheating. Even parents might utilize a lie detector to make sure their children (usually teenagers, since it is easy to tell when young children are lying) are not lying. There are of course many other uses.

Of course, most people find this very convenient. Employees need much less supervision. Students can take tests at home. Parents do not have to worry about their children doing bad things.

But a very small group of people do not like the lie detector tests. Some find them invasive. Some are opposed on obscure religious grounds. And, unfortunately, some people just want to lie without getting caught.

We will focus on people who are not trying to lie, but do not want to be lie detected for some other reason. How can they avoid being lie detected? (EDIT: Clarification. When I say "lie detected", I mean that the lie detector is used on them. It does not matter if it actually detects a lie or not.)

Some notes:

  1. Technically, it is never legally required to take a lie detector test. That being said, people can deny you employment, schools can expel you, and people can choose to assume you're a liar if you don't. Additionally, in a court of law, no testimony is accepted without a lie detector test, so if you are accused of a crime, you would not be able to testify in your own defense. More troubling, if someone commits a crime against you, you can not testify against them. Indeed, police will not even start an investigation without the person reporting the crime taking a lie detector test (unless they have extremely convincing evidence).
  2. This probably is not important, but I will explain what the lie detector actually detects. Technically, it is not a "lie" detector, but a "deception/misleader" detector. It detects whether or not someone is trying to deceive or mislead someone. So for example, if you shoot someone and said "I did not kill that person", which is technically true since the bullet killed them, it would still register on the lie detector. Likewise, if you said "I witnessed the shooting at noon", when in fact you witnessed it as 11:58 a.m., it would not register on the lie detector, since you were not attempting to mislead, even though the statement is technically false. Essentially, whether a lie gets detected depends on intent, not the statement itself.
  3. In accordance with the Rule of Funny, if you state something with the intent of being paradoxical, such as saying "this statement is false", the lie detector will short circuit and fume with smoke, rendering it useless. It should be noted that this is not a great way to make friends.
  4. It is not possible to use a lie detector on someone without them knowing, and using a lie detector on someone without their consent would be assault, even if you are a criminal. There is currently a case in the Supreme Court about whether you can even lie detect terrorists.
  • $\begingroup$ Kind-of the same question: worldbuilding.stackexchange.com/questions/62572/…; except for the time period. $\endgroup$
    – kingledion
    Commented Nov 23, 2018 at 19:20
  • $\begingroup$ Just to be clear: the rule of your world is the ubiquitous use of lie detection tech (LDT) and you're asking how any arbitrary person could circumvent their use, not legally or philosophically, but systemically? In other words, starting a church that advocates the disuse of LDT on the basis of being a conscientious objector would NOT be an appropriate answer? $\endgroup$
    – JBH
    Commented Nov 23, 2018 at 19:24
  • $\begingroup$ @kingledion Same premise, similar but not the same question. That question is about how criminals would react. This question is how people uncomfortable with the idea of lie detection would react. $\endgroup$ Commented Nov 23, 2018 at 19:24
  • 2
    $\begingroup$ Its worth noting that 99.99% is too inaccurate for this to work. Yes, that sounds really accurate, but given widespread use of the technology where most people tell the truth (since they'll get caught otherwise) you'll end with a ton of false positives. One in 10,000 uses will trigger a false positive and given how widespread this is, that's numerous false positives every day. In fact, there are likely to more false positives than false negatives, raising serious doubts as to how useful this would actually be. $\endgroup$ Commented Nov 23, 2018 at 23:21
  • 1
    $\begingroup$ 😀 Have you read The Wheel of Time series by Robert Jordan? The Aes Sedai were magically bound to tell the truth - which made them the most skilled liars on the planet (and they were known as such, completely untrustworthy). It's human nature to lie (*ahem*, manage the facts). Humans will simply figure out how to express deception in a way the machine can't identify. $\endgroup$
    – JBH
    Commented Nov 24, 2018 at 0:12

6 Answers 6


How do the Amish avoid using electricity?

Schools use lie detectors. So do the police and employers. The obvious solution is to not use schools, police, or employers. Only work for each other, never report crimes to the police, and teach your kids at home.

The ability of an insular farming community to implement this method is obvious. But, believe it or not, this works in cities too. The above statement applies almost completely to various Orthodox Jewish communities that can be found in Brooklyn, and assorted other cities in the US. How do the Orthodox avoid driving on the Sabbath? They make sure they live within walking distance of the synagogue.

Furthermore, it is possible to form your own community, with your own community rules, if you want to have a functioning police force that does not use the lie-detector.

Finally, it is important to note that both the examples seen here are in-fact people that object to certain things on 'obscure religious grounds.'

  • $\begingroup$ This is a good answer. One "loose end" though is how to deal with outside criminals. If someone outside the community comes in, robs you, and then leaves, what do you do? $\endgroup$ Commented Nov 23, 2018 at 20:07
  • 3
    $\begingroup$ @PyRulez You don't do anything. Sometimes, you are just the victim. See: the Jews for the last 2,000 years. $\endgroup$
    – kingledion
    Commented Nov 23, 2018 at 20:49

Invent a medical condition and bribe a few doctors/professors.

The easiest way I can think of to avoid this is to provide a reasonable explanation to anyone who might use the lie detector why it can’t function on you. Then whenever anyone asks you to take a test you can roll out the testimonials of doctors and previous test results showing conclusively that you have ‘LieDetectorsDontWorkOnMe Syndrome’.

All it would take is a few talented liars/ properly medicated people that can ‘break’ the test (ie give spurious results on baseline questions) and a couple of papers submitted to appropriate journals/media outlets showing that a rare few people can’t be accurately judged by the lie detector. Let the story become increasingly well known. Bribe a doctor to give you a diagnosis (or forge some appropriate looking documents). Then, whenever anyone asks you to take a test, simply say there’s no point and show them your documentation. You might have a hard time if someone becomes suspicious of you, but that’s sort of the nature of this game.


I misunderstood the question being asked in my previous answer, so here is another try...

Lie Detectors should have trigger phrases which activate their detection functionality in the same way as "Alexa" and "Hey Google" work in modern voice controlled systems.

For a statement to be submitted for lie detection, it must be preceded by the phrase "I solemnly swear that...". The lie detector will then verify the validity of all statements by that speaker until a second trigger statement such as "End Lie Detection" is announced or until ten seconds of silence occurs.

Ownership of a lie detector which does not require such verbal control would be a felony.

In this way, an abstainer from this technology simply needs to refrain from pronouncing the triggering phrases.

  • $\begingroup$ Unfortunately, I think you missed another part of the question. The problem isn't people discreetly using the lie detector, or physically forcing you to use it. The problem is that, if your only strategy is to refuse to use the lie detector, then you won't have a job, an education, and people will assume you a liar. $\endgroup$ Commented Nov 23, 2018 at 19:53
  • $\begingroup$ @PyRulez, so you are asking "How can they avoid being lie detected?". To my untrained ear, that sounds like you are either asking... "how a person can avoid having their lies detected as they are participating in lie-detection?", or "how can they avoid participating in the lie detection in the first place?" I think I need to bow out and let someone else handle this one. $\endgroup$ Commented Nov 23, 2018 at 20:27

What about people with mental problems?

You have poor long term memory. Say you DID eat those cookies.

Yet next week your mom will ask if you ate those.

You honestly don't know, hence the lie detector won't blip due to no intent.

Now, say you consume pills that hinder your memory. Pills -> eat cookies -> "I don't remember touching the cookie jar."

  • $\begingroup$ A lie detector is still being used on you though. The point is that you do not want a lie detector to be used on you, not to hide a lie. $\endgroup$ Commented Nov 23, 2018 at 20:06
  • $\begingroup$ Then I missed the goalposts :) $\endgroup$
    – Gustavo
    Commented Nov 23, 2018 at 20:08
  • $\begingroup$ @PyRulez - it would work with Joe Blogg's answer, to get a diagnosis of "LieDetectorDoesntWorkOnMe" and/or discredit the machine's own accuracy, and thus avoid it in the future on the grounds that it doesn't well, work. $\endgroup$
    – Megha
    Commented Nov 25, 2018 at 1:43

You redefine your own definition of privacy. Using a lie detector on you is an attack on your privacy because the person could ask an inappropriate question and trick you into disclosing personal information.

It's very much comparable to smartphone use today. Everyone knows you have to register an account to be able to use the damn thing in the first place and all your information like games played, places visited and numbers called can be traced back to this account. And only very few people refuse to use a smartphone despite all of these potential breaches of privacy.

Since lie detectors are so widely spread and used in almost any situation, there have to be reported cases of abuse. Someone skillfully questioned a VIP and got answers that revealed much more than was nessecary to answer the question because the person wanted to avoid being caught at lying at all cost.

As long as using a detector on you against your will is considered assault, all you have to do is say:

I'm sorry but I'm not comfortable with being lie detected. Do you remember the VIP incident? It shouldn't be acceptable to ignore a person's privacy in such a degenerate way.


What you need to do is create and teach yourself a personal language, one which sounds a lot like English but has a few significant differences. The word "Yes" is pronounced "No" and "No" is pronounced "Yes". "Didn't" is pronounced "Did" and so on. When someone asks you a question in the presence of the lie detector, you must strive to be as truthful and complete in your answer as possible, but choose the language with which you speak your truth with consideration for your personal agenda. Also, no matter how many people happen to be in the room with you and the lie detector, always talk to yourself since you are completely fluent in both English and your personal language and know which is being used in any given sentence. In this way, you are still technically being truthful, with no intent to mislead the person you are talking to; so the lie detector should be happy with everything you say.

  • $\begingroup$ The point is that you do not want the lie detector to be used on you at all, not that you are trying to "pass" it. $\endgroup$ Commented Nov 23, 2018 at 19:34
  • $\begingroup$ Also, I feel like that counts as misleading. It's like saying "I didn't kill him, the bullet killed him" and OP said the lie detector would catch that. I think the implication being, if you say things in order to give the person a wrong idea, it will go off. $\endgroup$
    – Entity
    Commented Nov 23, 2018 at 23:44
  • $\begingroup$ @Entity, If the speaker was trying to communicate with someone else while switching between languages, then it would be an attempt to deceive which could be detected by the lie detector. But if the speaker is not trying to communicate with anyone else... if they are just talking to themselves... then no deception is occurring. $\endgroup$ Commented Nov 24, 2018 at 9:20

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