What is a polygraph?
A polygraph, commonly known as a lie detector, measures and records several physiological indicators such as blood pressure, pulse, respiration, and skin conductivity while a person answers a series of questions. The premise is that deceptive answers will produce physiological responses that can be differentiated from those associated with non-deceptive answers.
How accurate is a polygraph?
Polygraph tests are generally considered to be highly accurate. According to the American Polygraph Association, when conducted properly by a qualified examiner, polygraph tests have an accuracy rate between 87% and 95%. However, it is important to note that no test is infallible, and errors can occur.
What does a polygraph test measure?
A polygraph test measures physiological responses such as:
- Respiratory activity
- Sweat gland activity (galvanic skin response)
- Cardiovascular activity (blood pressure and heart rate)
These measurements are used to detect changes that may indicate deception.
What happens during a polygraph examination?
A typical polygraph examination consists of three phases:
- Pre-test Interview: The examiner explains the test process, reviews the case facts, and discusses the questions to be asked.
- Chart Collection: The examinee is connected to the polygraph instrument, and the questions are asked while physiological responses are recorded.
- Test Data Analysis: The examiner analyzes the recorded data to determine whether the examinee was truthful or deceptive.
Can polygraph results be used in court?
The admissibility of polygraph results in court varies by jurisdiction. In some cases, polygraph evidence may be admissible, while in others, it may not be. It is generally decided on a case-by-case basis.
What kind of questions can be asked during a test?
Polygraph test questions are typically limited to “yes” or “no” answers and must relate to past events of a factual nature. Questions should be clear, objective, and directly related to the issue being investigated. Questions about religion, politics, or sexual matters are generally avoided unless directly relevant to the investigation.
Are polygraph results confidential?
Yes, the results of a polygraph examination are confidential and can only be shared with the person who took the test and the individual or organization that requested the test. By law, the results cannot be disclosed to unauthorized parties.
Can I have someone with me during the polygraph test?
No, only the examiner and the examinee are allowed in the polygraph room during the test. This policy helps to avoid any distractions or interruptions that could affect the test results.
How soon will I receive my polygraph test results?
Results are typically available within 24 hours of the test. However, in some occasions it may take up to 72 hours. The examiner will review the data and provide a written report, which will be shared with the requesting party.
How many questions can be asked during a polygraph test?
Typically, a polygraph test can include one to four relevant questions per test. The number of questions may vary depending on the complexity of the case and the specific requirements of the examination.