If you have been charged with a crime in Florida, there is a good chance that the prosecution will ask you to take a polygraph test. The results are not usually reliable, and so they may be nothing to be gained from passing or failing the test. But it could impact your case to some degree.
Understanding a polygraph
A polygraph is not a lie detector, as it is commonly known; rather, it is an instrument used to measure a person’s physiological response to questions to gauge their truthfulness. The test is usually administered by a trained professional who will ask the person questions about the crime they are accused of.
How it works
A polygraph works on the principle that a person who is lying will experience an increase in their heart rate, blood pressure and respiration. The polygraph sensors connected to the fingertips and chest will pick up this increased physiological activity and show it on a graph.
The test begins with the examiner asking a series of control questions designed to elicit a physiological response from the defendant to establish a pattern on the graph. When satisfied, they will ask relevant questions about the crime. The examiner will then analyze the results of the test to see if there is a significant difference between the control questions and the relevant questions.
If there are, it may indicate that the defendant is lying about their involvement in the crime. However, it is important to note that many factors can contaminate a polygraph test, including anxiousness, manipulation or some drugs and medication. And, even if everything is catered for, the test will still not be 100% accurate. The American Polygraph Association found it to be approximately 87% correct. So you or your criminal defense attorney could challenge the credibility of the results regardless of your circumstances.
In Florida, defendants have the right to refuse to take a polygraph test. Only individuals on the sex offender registry are required to take polygraph tests as a condition of their probation. And even the results obtained will still be inadmissible in court. They solely exist to be used in therapy sessions to help the offender reflect on their past actions.