METHODS TO DETECT LIARS

Lying is a part of life. Each of us has told a lie or two. Unfortunately, some people do it more than others. And they don't just lie about little things, but about big things as well. Police and other law enforcement organizations have tried to find reliable scientific methods to detect liars. Here are some examples:

The Polygraph test

This machine was first developed by the police in the 1930s to try to detect if suspected criminals were lying. The process involved attaching tubes, cuffs and metal plates to the person's body to measure changes in respiration and blood pressure. And though some expertshave suggested that polygraphs today have an accuracy of at least 96 percent, others suggest that the nervousness and fear that a person experiences when hooked up to the machine produce sympthoms similar to those of lying. Those people consider the results of the polygraph test to be unreliable.

Thermal imaging

Thermal imaging technology is based on the concept that, when a person is lying, blood flow increases around the eyes. First developed to identify terrorists at airports, the accuracy of the machine has been brought into question, since flying can make many people nervous and produce physical sumpthoms similar to those of lying.

Brain fingerprinting

Another recent lie - detecting tehnology, brain fingerprinting, involves putting a helmet with various electodes on a person's head to measure certian brain waves that show whether an alleged criminal is familiar with certain object, like a gun used in a robbery. This tehnology, however, cannot distinguish between the criminal and someone who just observed the crime taking place.