Describe and assess the Control Question Test as an approach to polygraphist examinations. Be sure to address the following terms: relevant questions, comparison questions, false negative, and false positive.

Question

What will be an ideal response?

Answer 1

Answers may vary.For many years, a standard way to assess truthfulness was to measure signs of physiological arousal in combination with a specific questioning strategy. The polygraph (sometimes referred to as the lie detector) is a computer-based machine that measures blood pressure, electrodermal activity, and respiratory changes during questioning. Its use is also based on the premise that liars will exhibit a particular constellation of emotional responses that distinguish them from truth-tellers.The Control Question Test (CQT, sometimes referred to as the Comparison Question Test) has become the most popular approach to polygraphist examinations. The polygrapher asks a series of questions and focuses on responses to two kinds of questions: relevant questions and comparison questions. Relevant questions inquire about the crime under investigation (e.g., "Did you steal the law school's video monitor?"). Comparison questions are not directly concerned with the crime but are designed to induce an emotional reaction because they cover common misdeeds that nearly all of us have committed (e.g., "Prior to the age of 21, did you ever do anything that was dishonest or illegal?"). Most polygraphers consider a denial to be a "known lie." But subjects will deny, thereby providing a characteristic physiological response to a lie. Polygraphers expect that guilty subjects will be more aroused by the relevant questions (to which they must respond with a lie in order to maintain their innocence) whereas innocent subjects will be more aroused by the comparison questions (because they will worry that admitting to a past misdeed might make them look more like a criminal). Therefore, this procedure works best when innocent subjects lie or show greater emotional arousal in response to the comparison questions, and guilty subjects lie and become more emotionally aroused in response to the relevant questions. The level of accuracy has been of great concern in debates about the validity of the polygraph. Examiners are accurate when they expose liars and believe truthful suspects. They err when they believe that a liar is truthful (a false negative) or that a truthful subject is lying (a false positive).Advocates of polygraph procedures claim very high rates of accuracy, and in laboratory studies in which some participants are instructed to commit a minor crime, others are not, and then all are tested with a CQT, accuracy rates can be as high as 90%. Yet a panel of scientists who reviewed studies on the CQT concluded that it could discriminate lying from truth-telling at rates above chance, but far below perfection (National Research Council, 2003).No measure of physiological reactions can precisely distinguish between guilt and other negative emotions, such as fear, anger, and embarrassment. Although some studies show high rates of accuracy in distinguishing between subjects who are lying and those who are not, many scientists are skeptical of those claims.