Lie detector, a device to reveal lies through a heartbeat

In the realm of law, investigators often use lie detectors to reveal the true truth. Sometimes, if someone is applying for certain occupations, a lie detector is also needed during the interview. How does a lie detector work? And is it effective in finding the truth?

What is a lie detector?

A lie detector is a polygraph machine designed with special sensors to detect lies in humans. This tool was originally invented in early 1902. Over time, lie detectors have had many more modern and more sophisticated versions.

A lie detector basically works by recording and recording a person's reaction in the form of magnetic waves when he is asked a number of questions on an ongoing basis. You will be attached a number of sensors during the process to detect your vital organs, such as heart rate, respiration, and skin.

The psychological reaction that occurs when you say something, whatever it is, will unconsciously affect the work of the organs. Through sensors attached to your body, investigators can find whether there are abnormal changes in the three bodily functions above. The results are then immediately printed on a graphic paper. Examination through a lie detector generally takes less than 1.5 hours.

How does a lie detector work?

When you do the test with a lie detector, there are 4 to 6 sensors that will be connected to the body. There are also other digital sensor devices that are connected throughout the body to determine whether there are psychological changes when someone is lying or telling the truth. Here's how a lie detector works to detect lies.

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First, you are required to sit on a special bench in a certain room. Then, the polygraph machine's sensors will be attached to your body. There are 3 cable sensors that are commonly used in detecting lies.

• Pneumograph sensor, which is used to detect breath beats that are affixed to the chest and abdomen. This sensor works when there is a contraction in the muscles and air in the body.
• Blood Pressure Cuff Sensor , its function is to detect changes in blood pressure and heart rate. This cable sensor is attached to your arm. How it works is detected by the sound of the heartbeat or blood flow.
• Skin resistance sensor , to see and detect the sweat that is on the hand. This sensor cable is generally also attached to the fingers, so you know how much sweat is coming out when you are cornered and lying

Second, the examiner will ask you some questions about a topic, issue or case that you want to know the truth about. Then, they will read the graph and find out if there is an abnormal reaction or a graph that fluctuates. After the results of the graph are read by the examiner, the graph results will be used to determine whether you are lying or being honest.

Then are the results of the lie detector test effective?

A lie detector inspection is generally up to 90 percent accurate. But this does not necessarily apply to all cases. The reason is, this tool only monitors and shows reactions to psychological changes when you say something. Physical signs and "strange" signs that often indicate a person is lying, such as stuttering, sweating, or unfocused eye movements are not always indications of lying. These characteristics may indicate that you are nervous, stressed, or feel uncomfortable in a certain condition. In this case, it becomes the "object" of research. In general, everyone has a different style of speech, not to mention taking into account people's shrewdness to cover up lies.

Detecting lies is not an easy task, it tends not to be done with the naked eye. Lie detectors are still controversial among psychologists, because there is no standard of lying that can be measured through physical or non-physical means.