Lie detectors or polygraphs are instruments that determine physiological signals given by the sensors wrapped around the person being investigated. The purpose of these devices is to record the changes shown by the monitors based on the person’s cognitive load and emotional arousal. The one who is being tested will undergo a series of questions in order to come up with a conclusion to whether he is telling a lie or not.
Importance of Lie Detection in Criminal Investigations
The invention of polygraph was the idea of John Larson in 1921. He was a police officer at Berkeley while studying forensic science at the University of California. However, the main concept of creating the device was to help police investigations become more law-abiding. The FBI then used lie detector machines in 1936 to investigate criminal cases. The main objective was to modernise the way police officers performed criminal investigations.
Over the years, lie detection has also been proven effective in screening job candidates, particularly for public and private security positions such as in the NSA, FBI, and CIA. And today, polygraphs are helpful in law enforcement and government applications. It’s important, however, to consider state laws that cover the use of lie detectors in private companies to regulate potential abuse of privacy.
How Criminal Investigators Employ Lie Detection
Of course, the use of lie detectors should be done by professional and certified examiners. With proper implementation and accurate detection, the results for a criminal investigation can be more than helpful in unveiling the truth. But the ultimate use for interrogations is focused on one particular crime. The accuracy of polygraphs also depends on the examiner’s knowledge and skills. If each condition is prime, the outcome would be reasonably accurate.
Under a prime conditions the lie detector’s accuracy can be more than 90%, according to the American Polygraph Association. It’s highly recommended to work with skilled examiners and efficient polygraphs for more valid results. Sensors are attached to various parts of the body to monitor the heart rate, sweat, and blood pressure. Once the results are in, the examiners will evaluate them in order to arrive at a conclusion.
The following are the common challenges encountered by examiners when using lie detection machines:
- Before the test, an awkward interaction between the subject and the examiner may affect the results.
- The examiner should depend on the subjective interpretation of the measurement.
- Guilty people can deceive the examiners through controlled emotions like biting their cheeks.
- Innocent individuals who poorly react to the interrogation may be labeled deceptive.
- Typically, lie detection may take 2-3 hours, while requiring certified examiners to do the job accurately. This may be prolonged if the individual is anxious or easily tires.
- The polygraph test is fairly invasive since the sensors are attached to the chest and fingers. As a result, some people feel anxious.
Future of Lie Detectors in the Ireland
With the growing popularity of polygraph tests in the Ireland, it’s important to keep up with the innovations made in modernising these machines. The factors in detecting the honesty of a suspected person include pulse, respiration, and blood pressure. But the subtle changes made by the human eye also reveals dishonesty of an individual. Such changes cannot be hidden by the subjects, which make it effective in screening job applicants as well as suspected criminals.
The future of lie detectors is expected to change because of the new innovations developed by companies to prove accuracy and efficiency of the machines. In the coming years criminal investigation in Ireland, as well as other countries, will become more sophisticated than ever.