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Lie Detection- Liar Liar

Lie Detection, also known as deception detection, uses questioning techniques along with technology to record a person’s physiological response to questions and based on that it is determined whether a person is telling the truth or lying. It is not a perfect means to judge whether a person is lying but it is a better than average method.

The most commonly used technology to gauge a person’s truthfulness is a polygraph. William M. Marston invented the modern polygraph prior to 1921. He was a student of experimental psychology at Harvard University. A polygraph is also known as a lie detector. A polygraph is so named because signals from multiple sensors (“poly”) are recorded on a single strip of paper (“graph”). When a person takes a polygraph test, sensors are attached to his body.

These sensors record physiological responses to questions some of which are breathing rate, pulse, blood pressure and perspiration. Before a polygraph test commences, the questioner asks three or four simple questions to establish a baseline. This baseline can be thought as a measure of the person’s physiological response when he is telling the truth.

Emily-Ritter-taking-a-lie-detector-test

The answers to the questions asked to establish baseline are known to the questioner. Once the baseline is established the real questions are asked. A response which causes significant deviation from the baseline indicates that the person is lying. There are many companies that offer lie detection services, some of which are london polygraph, lie detector test and north london detectives. The accuracy level depends on the examiner’s interpretation of the records and not on the evidence recorded by the machine. Only a well-trained examiner can use the polygraph to detect lies with high accuracy. However, different people react differently to lying and so the polygraph test is not perfect. Although lie detectors are used in police work, it is for the most part legally unacceptable.

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