First Draft
The lie detector is not accurate to use in the court as the evidence.
Have you ever tell the lie? Or have you ever notice the other people's lying? I think most of people have the experience in both questions. But it is hard to distinguish lie and truth by oneself. Because we just guess it through some subjective information. And here is the device that can distinguish lie, the lie detector!
The goal of a lie detector is to see if the person is telling the truth or lying when answering certain questions. Nowadays the lie detector is used many ways. It has used in the police investigation and in the court as the evidence. Also we need to do the lie detector test to attain the job, because certain government jobs like the FBI or CIA require the lie detector tests.
According to the common notion about the lie detector, it is really accurate and reliable because it's result are based on the numeric data. But I think it is not accurate, so I argue that the lie detector's result for the evidence in the court is not proper. The evidence in the court can play the critical role in the trial. For these reasons, my argument is 'The lie detector is not accurate to use in the court as the evidence.'
Everyone knows distinguishing lie is not easy in the life and most of it is just guessing. And we can't feel sure about it. And here is the device that named 'lie detector', as I said in the introduction briefly. All the people will know the meaning of the lie detector instantly. Also the goal of lie detector.
In the court, the evidence plays important role in the judgement. Also it can turn the final judgement. But If the lie detector be used in the court as the evidence like nowadays, we have to worry about misjudgement of the lie detector. And there will appear people who have damaged from the inaccurate of the lie detector.
And here is new information. Do you know that there are two kinds of the lie detector? Maybe no. There are polygraph and FRMI. Also there are differences.
Polygraphs are devices that monitor a person's physiological reactions. A polygraph is the devices that are used to monitor changes occurring in the body. When a person is questioned about a certain event or incident, the examiner looks how the person's heart rate, blood pressure, respiratory rate and perspiration(sweatiness) change compare to normal levels.
Also, FMRI(Functional Magnetic Resonance Imaging) can distinguish the lie like the polygraph. However there is difference.
FMRI have several ways to detect. First one is using BOLD(blood oxygenation level dependant). This way's point is measure the oxygen amount in the blood of brain. Second one is cognitive subtraction. This process compares the picture of brain that telling lie and telling truth.
Both Polygraph and the FMRI are the ways to distinguish the lie, but polygraph record the physiological reactions. And the FMRI record the oxygen amount in the blood of brain and the picture of the brain.
According to my research, there are 3 limits for lie detector.
First, FMRI of cognitive subtration is just relative. Most of the people think the vitalized part of the brain have connection with the lie in the result of the FMRI. However, according to the study, there are some part that are vitalized in FMRI but have no relative with lie. So, it means there are some vitalized part that are not related with the lie. The part of the brain can be vitalized to just keep the balance in the brain or other reasons. We can't know exactly why the part is vitalized. So the FMRI of cognitive subtration is just relative and not accurate.
And following two limits are related with both polygraph and the FMRI.
Second, We can't remember all the thing exactly. There can be false memory. And why the false memory form? According to my research, if the social demands on individuals, people remember that pressure. And individuals can be encouraged not to think about whether their memories are real or not. It means people cannot realize true memory and false memory themselves. Even there is no accuracy that the true memory is really true.
Lastly, the way to measure lie(both of polygraph and the FMRI) is easy to interrupt from environment. The recent study found that interruption movement like moving the finger is let the credibility decrease about 33 percent. So the result of the lie detector is not accurate. Because the result can change as where to test, when the experimenter test, or even how the experimenter feels at that time.
I also find the information about change the standard to accept evidence in the court. In 1923, there was a boy named 'Frye' who was prosecuted with the robbery and murder. In his trial, the court rejected the evidence from the lie detector because the lack of the general acceptance. This precedent called 'Frye Rule' after this trial. And over the 50 years, this rule performed the standard of the acceptance the evidence. However, after the making the principle of the 'Dovert' in 1993, the lie detector's result started to accept in the court as the evidence. And nowadays the frequency of acceptance the result of lie detector increase. According to the statistics, from the making the principle in the 1993 to 2003, 19 states in the United States of America accept the evidence in the court. I think this tendency is not proper. And these three limits and one precedent can support my argument, that the result from the lie detector cannot be used in the court as the evidence.
Some people can be argue that the lie detector is accurate because it distinguish lie through physiological phenomena that recorded in figure. They think the figure is more accurate than the person's guessing. And they can argue if the person is guiltless and innocent, there is no reason to reject to do lie detector test. Also they may think the lie detector is a useful device in the court because it just can be used for reference to judgement. However these arguments are not logical.
First, in the research that I found above, there are information that tell the lie detector's record is just relative. So, even the record is in the figure or in the statistics, it is not accurate.
Second, opposing to their arguments, I think there are many reason to reject. For example, the person can be too nervous to have the examination or the person is just worry about the misjudged of the lie detector although guiltless. The lie detector makes the person nervous.
Lastly, if the lie detector used just for reference, it can also play the important role in the judgement. It will make the judge and member of the jury to think biased. And it can be used as the tool to get desired result.
Do you know the Korea Drama '7 level public official(7급 공무원)'? It is the story of the process that being National Intelligence Service(NIS) the kind of public officials. In the drama, there are some scenes that training lie detector examination to be the great NIS. They practice to not conceal their lie or to control their physiological reactions. I am not telling about this is reality of the NIS. I don't know this scene is true or not. I want to say, through this scene, lie detector can be manipulated by experimenters. It means, If someone tell the lie, the lie detector can say it's not lie! Because the person who are experimented are skilled at control his physiological reactions or conceal his lie easily. Like this, the lie detector is not accurate to be the evidence in the court.
Also, the lie detector's result is relative and people have many false memory that cannot realize themselves. And it's easy to interrupt by examination environment. For these reasons, I think the lie detector can't be the evidence in the court.
