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raven860's avatar

Is there any way to catch a liar?

Asked by raven860 (2179points) February 20th, 2011

Like hypnotism?

Or reading micro-expression?

Or truth-serum?

I think that this is a bit of a silly question but I just wanted to know. I think the ones mentioned above are either illegal, not possible, a myth or not very effective. My question is are there any similar techniques or instruments other than good old cross examination and lie-detectors. I ask because I had no knowledge of reading micro-expressions until recently.

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19 Answers

SmashTheState's avatar

Here is how you can definitely catch a liar:

(1) Get a politician.

Er, that’s it.

(Seriously, there is no reliable way to tell whether or not a person is lying. Sodium pentathol, micro-expressions, and the polygraph machine have all been debunked. There are a few general cues—for example, we know that people are more likely to make direct, sustained eye contact when lying—but they are far from reliable, and all can be manipulated by a skilled liar.)

flutherother's avatar

I don’t think there is a foolproof way as some liars believe the lies they tell. You can sometimes tell instinctively when someone is telling the truth but you can never be 100% sure.

saintDrew's avatar

Time is the greatest tool. The truth is always revealed in time.
and then there are certain body language signs you can read.

jaytkay's avatar

I have just a moment, so I can’t Google up a more exact answer for you, but detecting liars in face-to-face interviews is a skill and it can be taught.

It involves split-second facial expressions- people give away their true feelings in really quick bursts.

After reading about it I noticed very easily when first meeting a person, when they smile and say “hi” they either hold the smile, or they make a really quick frown in the midst of smiling.

Once you see it, it’s unmistakable. Someone is genuinely glad to meet you or they flash a really quick “ick, this is a chore” face.

WasCy's avatar

Aside from all of the ‘body reading’ that people try to teach, the way the police do this in interrogations (without torture or other coercion, of course) is probably the best way ever invented. Continue to ask the person to tell the story, and to add more and more detail each time. Record exactly what is said and go back to ask questions about that, and request more detail every time. Eventually, when you’re questioning enough detail, liars generally start to screw up by telling conflicting (or impossible) details.

choreplay's avatar

MSN had a post like this lately and had about seven points. Lets see what I can remember 1) excessive face touching or scratching their nose. 2) Their speech gets real formal like “I did not” rather than I didn’t and use proper names like John Smith rather than he or they. 3) Their smile is isolated in the mouth and half cocked rather than lots of facial expression from someone telling the truth. 4) They don’t make good eye contact and their eyes keep darting away from you. 5) Their body posture gets real closed like crossing of arms or putting some object between you and them. 6) Use a pause deliberately causing an awkward silence, if they are lying they will squirm or start to talk a lot explaining. 7) They over explain their actions with lots of information that wouldn’t have been needed. 8) If you change the subject their body language and mood reacts overly positively.

Guess there were eight. If you notice any of these happening beyond a shadow of a doubt I would point it out and see if they get even more uncomfortable. Hope some of these help.

ragingloli's avatar

An MRI maybe. The brain is much more active when lying.

wundayatta's avatar

It is true that there have been experiments with MRI lately, and they discovered that when people lie, certain types of brain activity often appears. However, that activity does not always occur when lying and when that activity occurs, a person is not always lying.

There are all kinds of methods, but none of them work all the time. The best thing to do is to gather evidence that shows the person can not be telling the truth.

perspicacious's avatar

You have to be quicker than they are.

Jeruba's avatar

I don’t think that’s necessarily so, @saintDrew. If the truth of something were never revealed, how would you know that? You might know when it is, but not when it isn’t.

And sometimes the truth is taken to be a lie, especially by people who are liars themselves (and think everyone else is too) and by people who have already made an emotional commitment to belief in a lie.

PhiNotPi's avatar

First off, microexpression reading and truth serums don’t work. Neither microexpressions nor truth serums really exist in any proffesional sense. Polygraph works very well, but can be beaten.

Anyway, the first step is to observe and notice if the person is acting any different than normal. Are they nervous or hesitant to speak when you don’t expect them to be nervous or hesitant? This may be a sign, but if this happens, DON’T make the assumption that they are lying, but you may wan’t to ask them if something is wrong. They may have a legitimate reason. Body language can be a sign too, but you would have to study body language to learn the signs.

With hypnosis, half of the stuff that you read on the internet, and almost always the stuff on stage hypnosis, is not going to be true. Even the notion of a subconscious mind is still being debated. Hypnosis cannot be used to get someone to do something that a person does not want to do. The “conscious mind” is always monitoring what is going on, even though it might not always seem that way. Getting a person to tell a truth when they don’t want to can be very hard. However, hypnosis with willing subjects can do very neat, scientifically important things, such as inducing mental conditions, like synesthesia, that are actually found in some people.

incendiary_dan's avatar

You need two things:

1) Incontrovertible proof that what they said is wrong.

2) Incontrovertible proof that they knew that what they said was wrong.

WasCy's avatar


Oh, yeah, I well remember, “I did not have sex with that woman, Monica Lewinsky,” accompanied by a stern visage and the pointing index finger.

Kardamom's avatar

There are also people who exagerate, and in their own minds they are not lying, but technically they are lying. There are also “lies of omission” like with the Monica Lewinsky example. He didn’t actually have sexual intercourse with that woman, but he certainly had a sexual experience with her. And then there are people who are pathological liars. People who might say everything from “I ate a sandwich for lunch” when they actually had tacos to “I’ve never met that woman before” when in fact they were married. Those kind of people are very difficult to deal with unless you, yourself, have all of the facts. They are very convincing liars.

kalrbing's avatar

If you are trying to catch someone you associate with on a daily basis, Alcohol may be a great alternative. Yes, this does require you to stoop to their level, but I have found out the truth more than enough from a drunk friend. I mean this in the most serious way possible

Jenniehowell's avatar

I would assume it’s hard to get a liar (or anyone for that matter) to sit still long enough to deal with the alleged lie detecting contraptions or procedures. If it were me & I was trying to catch a liar – I’d record them saying whatever they said & me challenging it to them along with their response & justification & then I’d expose them to the truth by researching it etc. When they denied their lie I’d simply email them the recording – simple as that – you have proof of the truth & proof that they spoke contrary to that truth

I’d seriously consider whether that effort was worth it or not when in many cases you can simply rid yourself of the drama & time wasting by just ridding yourself of spending time around liars. Sometimes we don’t have a choice (ie family, co-workers, employers etc) but as much as I could ignore/avoid a negative person I would & liars are definitely negative people.

If you’re not a cop, psychologist or some field where proofs are needed fir such things or in a workplace predicament in need of proofs I’d seriously question why a person would care to catch the liar. Outside a few logical scenarios the only reason to catch a liar is to let them know they were caught or to expose them to others & that seems like an overboard level of attempts to control or influence people when you could just leave them to figure it all out on their own.

I guess my point is prove it if you have to for some legal or occupational reason, but if you don’t then just drop them from your orbit so you can release the chaos liars bring to the lives of those around them.

augustlan's avatar

I have a very good built-in lie detector, and people are often stunned by my ability to know when they are lying. However, I have no idea how it works, and, of course, no clue as to how many times it hasn’t worked at all.

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