9 Things I Wish I'd Known About Polygraph Tests Before Hiring an Examiner

Polygraph tests, commonly referred to as lie detector tests, are a longstanding tool within the forensic sciences. Utilized predominantly for criminal investigations and employment screenings, these tests have a fascinating and complex history. Yet, they come with their fair share of controversies, misconceptions, and practical limitations. Drawing from the various intellectual disciplines such as law, psychology, and statistics, we will delve into nine areas of polygraph testing that I wish I had known before hiring an examiner.

The first thing to know is the origin and the principle of polygraph tests. Contrary to popular clichés, the polygraph doesn't detect lies. Rather, it measures physiological responses such as blood pressure, pulse, respiration, and skin conductivity while the subject answers a series of questions. This technology was developed in the early 20th century by John A. Larson, a medical student at the University of California, Berkeley. However, the scientific validity and reliability of the polygraph are hotly debated topics in both the legal and psychological fields.

The second consideration is the application of polygraph tests. They are frequently used in criminal investigations and employee screenings, particularly in sectors requiring high security clearance. However, the use of polygraph tests in these contexts has raised numerous ethical and legal questions about individuals’ rights to privacy and self-incrimination.

Thirdly, understanding the polygraph examination process is crucial. The process consists of three stages: a pre-test interview, the data collection phase, and the post-test analysis. The pre-test interview involves a discussion between the examiner and the examinee about the test, the questions to be asked, and the subject's rights. The data collection phase includes the recording of physiological responses to questions. Lastly, in the post-test analysis, the polygraph examiner evaluates the data to determine if any physiological responses indicative of deception were present.

The fourth aspect of interest is the type of questions asked during the examination. A polygraph test typically includes "control" questions (general questions such as "Have you ever lied to get out of trouble?") and "relevant" questions directly related to the issue under investigation.

The fifth point of interest is interpretation, which is a core component of polygraph examinations. The interpretation of physiological responses can be subjective and depends significantly on the examiner's training and experience. This subjectivity leads to a degree of uncertainty in polygraph results, which can be statistically quantified using the Bayes theorem.

Number six on the list is the accuracy of polygraph tests, a controversial topic among experts. Some studies suggest an accuracy rate above 90%, while others propose figures as low as 56%. This discrepancy can be attributed to various factors such as the quality of the questions, the examiner's proficiency, and the examinee's physiological and psychological state.

The seventh item concerns countermeasures, techniques that can be employed to manipulate the outcome of a polygraph test. These range from physical tactics, such as controlled breathing or muscle tension, to psychological methods like cognitive load theory.

The eighth point of note is the legal status of polygraph results. In the United States, the admissibility of polygraph results in court varies widely from state to state. The Supreme Court case United States v. Scheffer in 1998 ruled that federal courts could uphold blanket bans on polygraph evidence, leading to an inconsistent landscape of legal acceptance.

Lastly, it is imperative to remember that a polygraph examination is a tool, not a definitive solution. Despite its limitations and the many controversies, when used correctly and ethically by trained professionals, it can provide valuable insights in specific investigative contexts.

Engaging the services of a polygraph examiner requires a thorough understanding of these nine aspects. This way, one can navigate the complex terrain of polygraph testing with informed confidence, maximizing its benefits while minimizing its potential pitfalls.