In 1935, the first lie detection test was held in a court of law . The machine was only used during trial as it was considered admissible evidence. Both the prosecutor and the defense agreed to use it. Since then, the machine has been in use and has become a great ally in criminal investigation cases.
Created in 1921, the polygraph is a machine capable of detecting lies . To know whether or not a particular individual is telling the truth, the polygraph assesses physiological changes. The test compares breathing rhythms, blood pressure, heart rate, and more when certain questions are asked.
In trials, the test is never accepted as definitive evidence , but may serve as the basis for a legal decision. Here in Brazil, the use of polygraph is prohibited. Being considered a variant, many believe the polygraph doesn’t really work.
Does the polygraph work?
There is a lot of controversy, of course. According to experts, the equipment has failed numerous times. There are cases of suspects who managed to fool the detector but later confessed to their crimes. Still for experts, the test generates many false positives, that is, many may even tell the truth, but the test suggests they are lying.
In other words, there is a 50% chance of a polygraph test saying that an honest person is lying. However, interrogation technicians rely on answers they know to be true. They therefore provide a baseline against which misleading responses can be judged as an increase in nervous arousal.
The fact, however, is that many know how to trick the equipment. The clever dribblers say the secret is to answer the questions calmly. Just keep the basal breathing pattern. Your mind must be calmer knowing that you – not the polygraph – are in control. And even if you make a slight change, just induce your body to have more control in the next responses.
Because of so many failures, the National Research Council of the United States – has conducted a systematic assessment and concluded that the test lacks rather of scientific validity. In 1998, the US Supreme Court began to restrict its use in court proceedings. In particular, defense attorneys can no longer use evidence from polygraph tests to establish the innocence of a crime.
Even though polygraph testing has been disabled in legal proceedings, its use in other scenarios has also decreased. Employers, for example, cannot use it as a technique for recruiting employees. On the other hand, for the US government, this is an exception.
The comeback
President Donald Trump has nominated the judge for a lifetime position in the country’s highest court, which has the final say on controversial topics such as abortion and gay marriage. But allegations of sexual harassment against him delayed the appointment. It was during the Senate committee hearings in October that polygraphs were mentioned again.
President Donald Trump has nominated the judge for a lifetime position in the country’s highest court, which has the final say on controversial topics such as abortion and gay marriage. But allegations of sexual harassment against him delayed the appointment. It was during the Senate committee hearings in October that polygraphs were mentioned again. The device was mentioned because Christine Blasey Ford underwent a polygraph test after accusing Kavanaugh of trying to sexually abuse her while in high school. He, who denies the charge, did not go through a lie detector.
