The polygraph, also called the lie detector, has a colorful and controversial past in the United States. This device was first created in the late nineteenth century. The modern adaptation is an electromechanical device that is attached to an individual’s body during an interview or questioning session. Many in the scientific community have rejected the polygraph device as pseudoscience (method claiming to be scientific but fails to adhere to appropriate scientific methods or lacks evidence). However, some countries continue to use the polygraph as a tool for interrogation.
Polygraphs in General
The polygraph is a device that measures and records several physical markers, such as blood pressure, pulse, perspiration, and breathing rhythms. These physical responses are measured while the individual is asked questions. The reasoning is that lies or any deception produce physical responses that are different from the responses produced when answering truthfully. Today, the polygraph is a subject of ongoing controversy and in most states in the U.S. the polygraph test results are not admissible in court.
In the United States, polygraph tests are often used during police investigations, but no defendant or witness can be forced to take the test. In a 1998 United States Supreme Court case the Court stated it was up to the individual state’s discretion whether polygraph results could be admitted as evidence in court cases. In 2007, polygraph testimony was admitted by stipulation in 19 states and subject to the judge’s discretion in the federal courts.
In 1993, an important case altered an old evidentiary standard (Frye standard) and held that all forensic evidence (polygraphs included) must meet the Daubert standard, which requires that the “underlying reasoning or methodology is scientifically valid and properly can be applied to the facts at issue.”
Today in the U.S., the polygraph is still used by prosecutors, defense attorneys, and police agencies. New Mexico admits polygraph testing before juries in certain situations. In other states, the polygraph examiners are allowed to testify before judges in certain hearings (such as motions to revoke probation or motions to adjudicate guilt). Some federal government agencies (such as the FBI and CIA) as well as some police departments (such as LAPD) use polygraph tests to interrogate suspects and examine potential new employees.
Modern discussions of the polygraph remain controversial. However, one area in which polygraph tests are used extensively is in post-conviction supervision, especially for sex offenders.
Importance of Speaking with an Attorney
If you would like more information regarding the polygraph test or its admissibility in court, contact an attorney in your area. A skilled attorney can help navigate your state’s laws and court procedures.