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The Contender
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6 Points

Can lie detectors be used in court

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Voting Style: Open Point System: 7 Point
Started: 4/9/2013 Category: Society
Updated: 4 years ago Status: Post Voting Period
Viewed: 1,997 times Debate No: 32269
Debate Rounds (3)
Comments (1)
Votes (1)




Most people fail to realize however that the main value of the polygraph process is not the test itself but the results of the interview before the test and, if there are signs of deception, the interrogation after the test. If you lie, and get caught lying by the instrument, all you need to do is keep your mouth shut or leave afterwards (if you are not under arrest) and nothing can be done. Many people stay afterwards and they end up confessing in the interrogation portion afterwards. THAT is admissible, at least up here.


I accept the debate that is posted.

I will allow my opponent to make their argument first, but I will summarize my objective in round one. I will try to show that a lie detector or polygraph has major flaws. That there is many better alternatives to the lie detector in proving someone's guilt. That it is very possible to make a lie detector results invalid.

I will like to thank my opponent and wish my opponent the best of luck.

Debate Round No. 1


Polygraph testing, now one of the most extensively employed forensic procedures, has been used in the investigation of crimes in the U.S. since the early 1900s. It is also widely used in many other countries, including Canada, Japan, and Israel. The value of the testing is said to lie in its helpfulness in exonerating innocent persons suspected of crimes. Polygraph results are admissible as EVIDENCE, in some U.S. courts. In many cases admissibility depends on mutual agreement by the opposing parties, although a few state courts have admitted polygraph results over the objection of one party.


Lie detectors should not be used in court because the results can be invalid and there is already in place much better forensic evidence alternatives in proving someone's guilt or innocence.

First of all lie detectors do not detected lies they instead detect a person's blood pressure, heart beat, respiratory rate, and perspiration then ask a question (example: Where were you on the night of June 11, 2013) then the polygraph examiner compares the results to the person's normal levels if there is dramatic change in the results it can be interpreted as a lie. This has problems because is it not logical to assume that someone can get away with lying as long as they are calm under the questioning even if they are guilty or if you take a nervous person and ask them tough questions that could cause stress that they could look like they are lying while in reality they are not. This has lead to more false positives then false negatives when it comes to testing which means more innocent people are looking guilty then guilty people looking innocent. If a case is all dependent on a lie detector results it could more likely to send a innocent person to jail than a guilty person free. This is way Lie detectors should not be used in court.

To my final point I will show much better alternatives than a lie detector for evidence. DNA (deoxyribonucleic acid) has proven to be 99.99% accurate with non-tampered evidence. Video severance has now become a major source of evidence when it comes to the courts because like the old saying "the eye in the sky don't lie" unlike a lie detector which can. Fingerprinting is still common and accurate no one person has the same fingerprint, palm print, foot print which means if a match occurs with a print it is very likely to be correct.

Lie detectors are becoming more advanced, but until they are able to detects lies then they should not be used in court.

Debate Round No. 2


Zhazirka forfeited this round.


I extend my argument

Vote con
Debate Round No. 3
1 comment has been posted on this debate.
Posted by Ragnar 4 years ago
Current commonly known ones, or up and coming ones which may be more reliable?

Since time of day is a factor to results, why is this not regulated into the interview schedules?
1 votes has been placed for this debate.
Vote Placed by Subutai 4 years ago
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Total points awarded:06 
Reasons for voting decision: FF. Also, better arguments by con.