ABOUT LIE DETECTOR
Lie detector is a one kind of machine or systems use to detect telling lie. Actually, it is monitoring several parts of body movement when a human answers a series of questions. It is monitoring only those parts which are not controlled by the conscious mind. Some lie detector may build in on the basis of human pulse, blood circulation or respiration system. Actually, this system is made on the basis of some hypothesis. In many experiment it is found that when people tell a lie, there are some reasonable change in his/her blood circulation, or in skin conductivity or in any physical change. Some people exist who do not tell a lie in front of other’s eye. Some exist when they tell a lie they become sweating. Considering this kind of hypothesis, this detector is invented. Some detector considers skin conductivity by electric circuit & tries to find the abrupt change of conductivity when the man answers a series of questions.
Basically, lie detector is made on polygraph taste. Polygraph taste is not scientifically approved. Science does not give it the right of detecting lie. Though, this taste is being used by many organizations especially by detective agencies or by police. They mainly use this detector to interrogate criminal or checking new comer in their organization. Usage of this detector mainly started on U.S.A first. Their govt. investigation agencies implied this polygraph taste on their criminals. They implied this technique to check their investigation. Sometimes this detector might be use against some valuable confidential prisoner. This may be use for showing afraid to the prisoner. Maximum people become afraid in front of this detector, though it is not qualified machine to detect lie at all. Sometimes, innocent people may be sentenced to guilty by this machine.
Polygraph or lie detector method is not considered as a solid proof in the most of the court of the country in the world. Its success percentage is fifty. There are several tricks to pass in the polygraph test. If anyone is so confident and fearless in polygraph test he can be overcome the test. Most of the countries treat this test as a psychological test. Psychologists use this test in their many experiments. Sometimes, drugs may be used as detector to catch lie. Like L.S.D, Marijuana etc are used as hallucination materials. There are many experts in polygraph tests who are work for you or your company when you needed. For this case you must be noticed them before investigation. They need some hours to set up instrument & to set up questions what are asked to the examinee. You can easily find such kind of experts by web search in your locality.
Detectives, investigators, spies use this lie detector machine for various purposes. Though this machine is not 100% scientifically proofed many investigation agencies & govt. law enforcement agencies implied this technique on their prisoner. There are various types of lie detector or polygraph. There are some signs when a people tell a lie. When people tell a lie he wants to avoid eye contact. Most of the cases a liar person should behave defensive when he attacks by claim. And an innocent people often do aggressive behave. Some types of people shaking their hands or legs or tries cover up their mouth by hands when they tell a lie. This type of physical change can be easily noticed by eye observation. There are some changes in human body internally like blood pressure change, skin conductivity change or blood pulse change. This change is not occurred in a constant rate in all human body. Some people are expert in hiding their expression in telling a lie. They can confidently tell a lie. For these kind of people lie detector test may be helpful for a company or agencies.