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Polygraph/Lie Detector

The polygraph, popularly known as the “lie detector”, is an apparatus invented in 1921 by a medical student at UC Berkeley, who was also working at the time as an officer in the Berkeley police department. Since then, the polygraph has become widely accepted as a means of determining whether or not a subject is telling the truth.

The polygraph (the word means a graph that measures multiple phenomena) operates on the principle that a person’s physiological responses differ when they are telling the truth and when they are lying. The standard polygraph measures blood pressure, pulse, respiration rate and electrodermal activity. The examiner (the polygrapher) asks the subject a variety of questions (both relevant and irrelevant to the topic for which the test is being administered) noting the subject’s response each time a question is answered. There is no one standard human physiological response when lying; the polygrapher’s craft is to determine how a particular subject reacts when not telling the truth. The ability of the polygrapher to gauge these responses is essential to an accurate polygraph test.

The FBI and police departments routinely use polygraphs as part of their interrogation processes. Federal, state and local governments also routinely use polygraph examinations when screening employees, especially those who require security clearances.

Private companies are strictly limited in their ability to have applicants and employees submit to a lie detector test. (See California Labor Code §432.2). The State of California does, however, allow for employers to request an applicant or employee to undergo a polygraph test (provided the subject is informed in writing of his or her right to refuse to take the test.)

As a result, in California, polygraph tests can be useful to employers in certain circumstances. They can also be useful to individuals, as, for example, a means of settling doubts to rest as to whether a family member is lying about such things as drug use, stealing, or even infidelity. People don’t generally think about private use of the polygraph, but it has its applications in daily life as well as with employers and the police department.

As part of our California private investigator services, John A. DeMarr PI is able to offer polygraph testing to our clients. We have experienced and certified polygraphers on call with portable equipment they can bring to any location at which a client wishes for a lie detector test to be administered. Our polygraphers have all worked with law enforcement agencies, and have all produced reports used as evidence in civil and criminal trials.

A polygraph test is only as good as the polygrapher administering it. We provide our clients with only the finest polygraphers in the field. If you need to have a polygraph administered, we know you’re not looking for a parlor game. You’re looking for a professional who can give you definite answers to your vitally important questions.

To arrange to have a polygraph taste administered, please call 877-433-6277 for a free consultation and price quote. You may also contact us by email, using the convenient form below.

Polygraph/Lie Detector – Free Consultation
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