The truth can be elusive, and so people have devised a lot of techniques to weed out lies. One of them is to use a lie detector during investigations. This has become so ingrained in popular culture that we often see or hear it in the movies. It does create a lot of drama but its accuracy is contested by many. To understand why this gained traction and why others are opposed to its use, we must delve deeper into the subject. Those who would like to try it out for themselves can also pay for a lie detector test London service for a reasonable fee.
The Setup
Lie detector testing requires three main components: the subject, the tester, and the machine. The tester will ask a number of questions which the subject must answer. The latter is strapped to the device so that his vitals can be monitored. The theory is that truths are easy to provide and should cause no observable changes in a person. Lies, on the other hand, are thought to be more taxing on the brain and perhaps the conscience. They cause visible fluctuations that will be shown by the device. Of course, all of these will have to be evaluated by an expert before conclusions can be reached.
The Machine
Polygraph machines or lie detectors have massively evolved since their initial invention. The overall design has remained with body sensors attached to a central unit. These can measure heart rate, respiratory rate, blood pressure, galvanic skin resistance, and so on. For instance, a spike in heart rate will raise a red flag. In the past, the readings were printed in real-time on a roll of paper. These analog units have been displaced by digital ones. Now that the central unit is usually a specialized laptop, the results can be flashed on the screen and analyzed accordingly by a forensic psychopathologist. They feature much more advanced algorithms to increase accuracy.
The Controversies
While lie detectors can provide interesting information about a subject, critics are doubtful about their ability to spot lies. It has been shown that certain individuals can control their vital signs through meditation and other techniques, allowing them to say anything during a test without disturbing their normal patterns. On the flip side, people who may be telling the truth can still show abnormal vitals due to their emotional response to stress. They may not be lying but the algorithm might think that they are. An experienced examiner can minimize the effect of stress on the outcome and arrive at viable results.
