Lie detectors or polygraphs are instruments that conclude physiological signals given by the sensors wrapped around the person being examined. The intention of these devices is to witness the changes shown by the monitors based on the person’s cognitive load and emotional stimulation. The one who is being tested will go through a series of questioning so as to come up with a conclusion.

The use of lie detector should be done by specialized and certified examiners. With proper execution and accurate detection, the results of an unlawful investigation can be more than supportive in unveiling the truth.  Under a primary condition, the lie detector’s correctness can be more than 90%, according to the American Polygraph Association. It’s highly suggested to work with skilled examiners and efficient polygraphs for more valid results. Sensors are attached to different parts of the body to monitor the heart rate, sweat, and blood pressure. Once the results are in, the examiners will estimate them in order to arrive at a conclusion. The following frequent challenges are faced by examiners when using lie detector,

  • Before the test, an uncomfortable interaction between the subject and the examiner may affect the results
  • The examiner should depend on the individual interpretation of the measurement
  • Blameworthy people can mislead the examiners through controlled emotions like biting their cheeks
  • Innocent individuals who poorly react to the interrogation may be labeled deceptively
  • In general, lie detection may take 2-3 hours, while requiring specialized examiners to do the job truthfully. This may be lengthened if the individual is fearful or easily tires.
  • The polygraph test is quite invasive since the sensors are attached to the chest and fingers. As a result, some people feel nervous.

With the growing popularity of polygraph tests, many countries are making use of it. The factors in detecting the honesty of a suspected person take account of pulse, respiration, and blood pressure. But the slight changes made by the human eye also expose dishonesty of an individual. Such changes cannot be unseen by the examinees, which make it effectual in screening job applicants as well as suspected criminals.