A polygraph test is commonly referred to as a lie detector test. The polygraph itself is a device or the procedure in which several physiological indicators are measured and recorded. These indicators include blood pressure, pulse, respiration, and skin conductivity. A person is asked questions and their physiological indicators are measured while they answer.
The purpose of this is to attempt to correlate the two with telling lies. It is assumed that when you lie in response to a question, your blood pressure will rise, or you will exhibit other physiological responses.
In the past, polygraph tests were often used by police, as well as government agents, employers, criminal investigators, and attorneys, in order to interrogate suspected criminals. Recently, however, the accuracy and reliability of these tests have come into question and the tests have been utilized less frequently.
These tests are often unreliable indicators of lying because the factors that they measure are also factors of nervous excitement, anxiety, etc. Obviously, the polygraph process would cause some anxiety and would thus skew the results. Nervousness is not exclusive to those who are guilty of any wrongdoing.
In the United States, there is no state in which a person can be forced into taking a polygraph test by the police, or anyone else for that matter. However, most people are not aware of this fact. Police can often psychologically pressure a suspect into taking a polygraph test because the suspect has been made to believe that refusing to take the test is an automatic admission of guilt. The suspect may be further harassed and searched, until some kind of evidence has been found.
It is important to remember that you are never under any obligation, legal or otherwise, to take a polygraph test during a criminal investigation. Because of the inaccuracy of these tests, voluntarily taking one to prove your innocence could backfire.
Further, if the police have already considered you a suspect, there is the risk that they may believe that you “beat” the test, rather than believe that you actually told the truth. Polygraph tests can result in lose-lose situations.
If a criminal investigator is asking you to take a polygraph test, you should assume that they are attempting to gather evidence against you. In any sort of criminal investigation, there must be enough evidence to convince the court or a jury that the suspect has committed a crime, beyond a reasonable doubt. The gathering of evidence is not restricted to the physical test; generally, the test administrator will ask the subject some questions once the testing machine has been turned off.
This is done because the subject will likely feel more comfortable once they believe the test has concluded, and might make statements or omissions that the investigator may later use as evidence in court.
The admissibility of a polygraph test are not universal in all criminal cases. Almost every state can be divided into two categories: those that find the results of polygraph tests completely inadmissible, and those that allow their admission with the stipulations of both parties. This means that both the suspect and the prosecutor have agreed to admit that the test results are evidence.
California, Arizona, Nevada, Georgia, and Florida are a few of the states that allow the tests if everyone involved agrees to them, but may apply different emphasis on the test’s accuracy:
- California attorneys may present the test results to the jury, allowing them to draw from it whatever they may;
- Georgia, in contrast, allows defendants who suffer damage because of a false result on a polygraph test, to sue the test operator for damages and attorney’s fees; and
- Florida is the one state that actually requires some people to submit to polygraph testing, such as previously convicted sex offenders, but even in those situations the test results cannot be used against them in court and are only for use in the course of their therapy.
In the states in which the test results are deemed inadmissible, even if both parties wish to enter the test results into evidence, it is forbidden except in very rare circumstances. States such as New York and Texas forbid their use completely in all employment and law enforcement context. Other states do not allow the test results to be submitted as evidence, but do allow for the use of them as supporting probable cause to obtain search warrants.
Federal courts have their own rules on when to allow the admission of polygraph test evidence, and it is generally at the judge’s discretion. In non-criminal situations, such as employment settings, it is a general rule that employers may not use polygraph tests in order to screen potential employees, or to obtain information from current employees.
Polygraph test usage in employment situations is typically limited to those in which the employer has a good, work related reason (such as suspicion of theft), and the test must be narrowly focused.
It is imperative to remember that you are not at all legally obligated to submit to a polygraph test. Obtaining an attorney is absolutely essential in defending your rights. A skilled and knowledgeable criminal defense attorney will help you determine and protect your rights. They can also inform you of any applicable state laws, and represent you in court.