Polygraph tests, also known as lie detector tests, are sometimes used by law enforcement during investigations. While not admissible in many courts as definitive proof of guilt or innocence, the results can significantly influence an investigation. Understanding the types of questions asked during a police polygraph is crucial for anyone facing such a test. This article will explore the common question types, providing insight into the process and strategies employed by investigators.
Types of Questions Asked During a Police Polygraph
Police polygraph examinations typically involve three main types of questions: irrelevant, relevant, and control questions. The careful construction and sequencing of these questions are key to the polygraph examiner's interpretation.
Irrelevant Questions
These questions are designed to establish a baseline for the subject's physiological responses. They are unrelated to the case under investigation and should elicit truthful answers. Examples include:
- "Is your name [Subject's Name]?"
- "Is today Tuesday?"
- "Were you born in [Subject's City]?"
The examiner monitors the subject's physiological responses (heart rate, blood pressure, respiration, skin conductivity) to these questions to establish a baseline of "normal" responses. Any significant deviation from this baseline during the relevant and control questions is what the examiner analyzes.
Relevant Questions
These are the core questions directly related to the crime being investigated. They are designed to elicit truthful answers if the subject is innocent and deceptive answers if the subject is guilty. Examples might include:
- "Did you kill John Smith?"
- "Were you present at the scene of the robbery on Main Street?"
- "Did you steal the money from the cash register?"
The phrasing of these questions is critical. Ambiguity can lead to misinterpretations, and the examiner will carefully word them to avoid misunderstandings. The subject's responses to these questions are compared to their baseline responses and the control questions.
Control Questions
These questions are designed to be emotionally arousing even for an innocent person. They are not directly related to the crime but address behaviors or actions that most people would consider undesirable. They are intended to provoke a stronger physiological response than the irrelevant questions. Examples include:
- "Before the age of 21, did you ever do something dishonest?"
- "Have you ever lied to someone you care about?"
- "Have you ever taken something that didn't belong to you?"
The comparison between responses to control and relevant questions is a key component of the polygraph analysis. If the physiological responses to the relevant questions are significantly less than the control questions, it might suggest truthfulness. Conversely, stronger responses to relevant questions might suggest deception.
The Importance of Pre-Test Interview
Before the actual polygraph test begins, a pre-test interview is crucial. During this interview, the examiner will:
- Gather background information: This helps the examiner tailor the questions and understand the context of the case.
- Explain the procedure: The subject is informed about what to expect during the test.
- Establish rapport: Building trust and a comfortable atmosphere can help reduce anxiety and produce more reliable results.
- Discuss the questions: The examiner will discuss the questions with the subject to ensure they are understood and to address any concerns.
Limitations and Criticisms of Polygraph Tests
It's vital to acknowledge that polygraph tests are not foolproof. They are criticized for several reasons:
- Subjectivity: The interpretation of the physiological responses is subjective and relies heavily on the examiner's experience and judgment.
- Countermeasures: Subjects can sometimes intentionally alter their physiological responses to try and deceive the polygraph. Techniques like controlling breathing or thinking of specific things can influence the results.
- Lack of standardization: There's no universally agreed-upon standard for administering or interpreting polygraph tests, leading to inconsistencies.
- Psychological factors: Anxiety, nervousness, and other emotional states can affect the results regardless of the subject's truthfulness.
Case Study: In the case of State v. Driver, the court admitted evidence of polygraph test results but still emphasized the inherent limitations and subjectivity of the test, highlighting the need for additional corroborating evidence.
Conclusion: Understanding the Questions and Their Limitations
The questions asked during a police polygraph test are carefully crafted to elicit specific physiological responses. The combination of irrelevant, relevant, and control questions allows the examiner to compare responses and draw conclusions. However, it's crucial to remember that polygraph tests are not infallible, and their results should be interpreted with caution. The subjectivity involved and the potential for manipulation mean that these tests should not be considered definitive evidence of guilt or innocence. Other evidence and investigatory techniques are necessary for a comprehensive assessment.