How Do Polygraph Tests Work?

Many people, particularly those who are accused of a criminal offense, wonder about how polygraph tests (often referred to as lie detector tests) work. Are they reliable, and what are the parameters used in determining whether someone is being truthful or attempting to "beat" the test? While the results of a polygraph test are inadmissible in terms of being used as evidence in court, those who face this often-stressful situation are interested in the accuracy of the results and how the test actually determines whether a person is telling the truth or not.

The fact is while someone's emotional state can impact the results, a person cannot control the outcome using his or her mind contrary to popular belief. Police have used lie detector or polygraph tests for more than a century in an effort to determine whether a suspect is being truthful or deceitful.

According to The Free Dictionary, polygraph tests work by using physiological responses to measure whether an individual is being truthful. Essentially, a suspect is fitted with sensors by a trained examiner before being subject to control questions, many of which are meant to make the suspect feel anxious or nervous. Some of the things measured during a polygraph text include blood pressure, respiration, heart rate, and even perspiration. In addition to measuring these functions, your expression, voice, or even movement or physical responses may be observed and come into play.

When taking a polygraph test, sensors are connected to the fingertips and chest, and the person administering the test explains how the test works along with how questions are worded. Initially the questions are easy and relevant to your age, name, where you live, etc. Once the basic questions are asked, questions regarding the alleged crime will begin and your reaction to the basic questions compared with those regarding the criminal investigation compared.

Because the results of a polygraph test are not always reliable due to the fact that breathing patterns, heart rate, and other indicators can vary in an individual in various situations, they are not admissible in court. Essentially, a person could be telling the absolute truth and the test record an increased heart rate or change in breathing, or lying without any discernible change in these factors.

Not really, and it could actually be detrimental. You gain nothing considering the results are not admissible in court, however if it is determined you were less than truthful in answering the questions asked, it could potentially harm your case. If asked whether you will submit to a polygraph test, politely decline. It has no bearing on your guilt or innocence, so it's best not to risk unreliable results.

Anyone who is under investigation for a crime or facing criminal charges should consult with a seasoned Orlando criminal defense attorney right away in an effort to protect your legal rights, freedom, and future.