Lie detector test were invented in the beginning of the 20th Century and are still being used extensively to determine deception and sabotage in the world. Lie Detection encompasses a lot of varying techniques such as polygraph, eye tracking and various others. We are going to look upon some of the most popular techniques which are being used and the level of success they provide in dealing with deception and fact checking.
Lie Detector Test, though widely used, is still an inexact science as results are not 100% accurate and vary from person to person. Some methods prove much more efficient than others and thus usage of them depends on the thought process and the general magnitude of the results needed. Some of the mainstream techniques which are used commonly are given below
- Polygraph Test– It is the most popular technique used in lie detector test and was the first one to be developed. Polygraph testing uses physical parameters such as heart rate, breathing variations and stress level to determine whether a person is telling the truth or not. Polygraphs are used by law enforcement agencies such as the FBI and CIA to interrogate foreign spies and criminals. The efficiency of polygraph test is around 80%-90% and is still not perfected fully. Future research can optimize the success levels but 100% efficiency is not expected as hardened liars can overcome such physical variations and master lie detection procedures.
- Cognitive Polygraph- Cognitive polygraph testing monitors the internal neural networks which are associated with a person’s decision making ability. They measure the flow of data in the neural pathways associated with familiar and unfamiliar recognition and the examiner can deduce the correct observation by studying this. Cognitive Polygraph Test, however effective has still not been proven by forensic science and therefore, its usage is massively limited.
- Eye tracking- it is another lie detector test process which observes changes in the optical function to judge deception. Examiners take note of pupil dilation, response time and reading or rereading patterns. It is very easy to perform and doesn’t cost much too. Though its usage are limited currently, Research in it is underway and the process is expected to become more fail-proof over time.
- Voice-Risk analysis- This method uses voice based signals such as pitch, frequency, intensity and micro tremors within speech of the test subject to determine deception or truthfulness. Success rates vary on the quality of instruments used to track these changes and can also fail sometimes.