It appears from the headlines today that Deborah Bradley, the mother of the missing 10 month old girl that disappeared from her crib in Kansas City, has failed a polygraph that was administered by the Kansas City Police.
For those of you who are unfamiliar with what a polygraph is, a polygraph is a test given to an individual while asking them a series of questions. During the test the physiological reactions to the asked questions are measured, and a “trained professional” determines by the results whether the individual is being truthful or not. Typically the examiner will be able to conclude whether the individual is being deceptive, truthful, or the test will be inconclusive. In other words, a polygraph is what is known as a “lie detector test.”
The fact of the matter is, the scientific community holds polygraph results to be less than credible. A psychology professor, right here at our own Boise State University, has opined that polygraph examinations give a high rate of false positives to innocent people.
When it comes right down to it, it does not make sense for anyone to submit to a polygraph examination. They are scientifically unreliable, and more importantly the legal community themselves, from police officers and prosecutors to criminal defense attorneys, all believe polygraph examinations to be voodoo. When a defendant passes a polygraph, the police insist that the defendant take another one, and when the defendant refuses, the police charge him anyway. Additionally, polygraph results have been held unreliable by the Courts, and for that reason polygraph results are inadmissible as evidence. That means neither the defense nor the prosecution may use them to prove innocence or guilt.
The sole purpose of a polygraph examination is for the interrogation value. The police tell you they want you to come down so they can “clear you as a suspect,” or “rule you out,” or “clear your good name,” etc. What the police are really doing is seizing the opportunity to interrogate you. They know they will have you over a barrel, and they also know that for all you know the polygraph examination is a credible examination, and so you will be honest and cooperative in hopes of passing the test. If and when you fail the test, the police will then take the opportunity to use that fact against you in the interrogation to break your spirit, and cause you to incriminate yourself even further. If you are lucky and pass the test, well they can still charge you, and successful polygraph results will not be admissible at a trial.
Never submit to a polygraph examination. It cannot help you, it will only hurt you. Always exercise your right to remain silent whenever a law enforcement officer directly or indirectly accuses you of wrongdoing.
Maybe Deborah Bradley is guilty, maybe she’s innocent, but the failed polygraph does not assist me in forming an opinion either way.