Truth Behind Lie Detector

Lie detectors

Most of us practice deception on some level in our daily live. Sometimes, you can tell when someone's lying, but other times it may not be so easy. we humans are no better than chance at detecting deception. Because  there is no single behaviour indicative of deception. what if you have a machine that can make this job easy. “polygraph “or a lie detector they monitor a person's physiological reactions. They do not detect lies rather they can  only detect whether deceptive behaviour is being displayed.

How do they work?

When someone tells a lie, they occur certain physiological changes in his body. Instances, Heart begins to beat faster leading to rapid perspiration, blood pressure and breathing pattern changes . polygraph is designed to record all these changes. So basically when a person undergoes lie detector test, various parts of the machine are attached to his body by  wires .And as a person is questioned about an event, the examiner looks for physiological changes in comparison to normal level. Fluctuations may indicate deception.

However, the polygraph is not wholly dependable. Its accuracy is estimated to be about 73%.Lot depends on the examiner. Some people who are truly unaware of the fact they are lying, cannot be caught .Moreover, people are capable enough to  control their emotions and render the machine ineffectiveness .Because of these reasons the result of a lie detector test cannot be accepted as an evidence.