Do you believe that lie detectors tell the truth?

Answer 1

Actually, no. I think they can be fooled. I would love to have a lie detector test. I don't think I'd believe they work until I was proved wrong.

Answer 2

There are numerous factors which may influence this answer. For instance, it can depend on (without the technical vocabulary, but with poor grammar instead!):

- The blood pressure of the person; e.g. some people may have different levels of blood pressure which can respond quickly or slowly. Some people may seem relaxed, since they can control this; others, however, may experience more problems with their blood pressure as they might react alot quicker under more stressful circumstances.

- Stress - in relation to blood pressure, some people may be able to control or manage their stress better than others. Whether they are speaking the truth (or otherwise, in certain situations!), they might find they react positively or negatively; i.e. the fight or flight instinct may 'kick-in'.

- Practise - some people have practise lying and still gain positive results from the lie dector. Other people have tried practising but for the opposite effect!

Nevertheless, whether someone is lying or not can depend upon what they answer, but what the original question was. For instance, 'did you steal the car?' may result in low blood pressure, where as 'dd you know who stole the car?' can result in a high blood pressure count. But, if evidence was presented to the person, the results and/or outcome(s) could be different; e.g. I was in the car but I was not the person who broke into it and drove it!

So, do we believe that lie detectors tell the truth? It depends on the person's blood pressure, stress levels and the personal pressure which the person is under; however, the ability to provide certain answers to particular questions has an influence too. Nevertheless, if the person has committed a crime, the question should really focus on 'Can lie dectectors seek a lie, rather than indicating the truth?'

Answer 3

The question is flawed. Lie detectors are incapable of lyiing, which would suggest that it makes a decision. Computers don't think. The question should be whether or not they accurately measure what they are supposed to. What if someone genuinely believes that they did not commit a crime they did commit? They would not have a measureable reaction. So, even if the detector were working, the technician's interpretation would still be innaccurate, even if he did everything right. How often does that happen, though? We don't know. So, the answer is we really don't know.

HJ (hjhop.blogspot.com)

Answer 4

They say that lie detectors are 96% correct but if your a fantastic lier then it dont work. Lie detectors work on heart rate and sweat levels and most people when they are tested cant controll these actions so it shows, in WW1 and 2 the men and women of service were trained to be able to defeat lie detectors to stop the information getting into the wrong hands.

Answer 5

I think shadow meant physiological responses. The lie detectors basically measure the skin's electrical resistance (or Galvanic skin response). The reason this can be used is because people are often more tense when they're lying (especially in the face of a professional polygraph) and this causes them to perspire - which is basically what the machine measures.

However some people can stay calm and beat the machine just by staying cool. They take several controls to judge your normal response so if somene is particulary nervous and or sweaty they can take it in to account by asking questions to which they know the response - eg 'what is your name?' 'where do you live?' and such.

Also it doesnt take in to account the fact that some people who will not trigger the machine are people who believe that they're telling the truth.

They serve a purpose but their readings and conclusions should be taken with a pinch of salt.

Answer 6

They are supposed to be 96% accurate and that is the reason they are not used in court. What if you happened to be the 4% that it didn't work on and were sent to jail as a result?! If it was being done on a cheating partner or whatever I am sure you would have an idea yourself what the results would say as you would have evidence supporting it before they even took the test. I would like to try one just to see what would happen. I would tell the truth on something and deliberately lie on the other just to see what the results were.

Answer 7

Lie detectors actually, called the polygraph, do not work. As psychology student I had a whole lecture about them with arguments for and against them. Personally my conclusions where that they must not be used. Even the British Psycholgical society don't believe they are accurate enough to be used in lie detection. They wrote a whole report about them.

"The polygraph is one among a number of procedures that could be used in attempts to detect deception and integrity but, like all procedures, it has inherent weaknesses. Error rates in polygraphic deception detection can be high. The most appropriate procedure or combination of procedures will
depend on the circumstances. Polygraphic deception detection procedures should not be ascribed a special status. We must not deceive ourselves into thinking that there will ever be an error-free way of detecting deception".

The link to the report is below if you are interested in the subject.

Answer 8

I don't think lie detectors KNOW that you are telling the truth. It's something to do with your pulse quickening when you knowingly tell a lie. Trouble is, if you're good at telling lies - how do you know whether the lie detector will know?
I think not

Answer 9

A lie detector is a machine, how can it tell the truth or lie? People are a different matter.

Answer 10

Lie detectors do not tell anything, they just measure. Pulse, perspiration, breathing to name a few. The data is then interpreted based on known standards by the polygraph examiner. The polygraph can be beaten. It is also possible that you could be telling the truth, but ruled as lying based on nervous actions. In short it is unreliable and is not allowed as evidence in a court of law. If you have to take a polygraph be aware of one thing. The examiners are not above lying themselves. The last one I had to take I passed without problem because I was telling the truth. When the test was complete they came in and told me I failed trying to get me admit to something that did not happen. When I told them how full of it their machine was they changed the story and said I passed.