Lie Truth Detector

[Octaviano Collars]

Theinstrument typically used to conduct polygraph tests consists of a physiological recorder that assesses three indicators of autonomic arousal: heart rate/blood pressure, respiration, and skin conductivity. Most examiners today use computerized recording systems. Rate and depth of respiration are measured by pneumographs wrapped around a subject's chest. Cardiovascular activity is assessed by a blood pressure cuff. Skin conductivity (called the galvanic skin or electrodermal response) is measured through electrodes attached to a subject's fingertips.

The recording instrument and questioning techniques are only used during a part of the polygraph examination. A typical examination includes a pretest phase during which the technique is explained and each test question reviewed. The pretest interview is designed to ensure that subjects understand the questions and to induce a subject's concern about being deceptive. Polygraph examinations often include a procedure called a "stimulation test," which is a demonstration of the instrument's accuracy in detecting deception.

Several questioning techniques are commonly used in polygraph tests. The most widely used test format for subjects in criminal incident investigations is the Control Question Test (CQT). The CQT compares responses to "relevant" questions (e.g., "Did you shoot your wife?"), with those of "control" questions. The control questions are designed to control for the effect of the generally threatening nature of relevant questions. Control questions concern misdeeds that are similar to those being investigated, but refer to the subject's past and are usually broad in scope; for example, "Have you ever betrayed anyone who trusted you?"

A person who is telling the truth is assumed to fear control questions more than relevant questions. This is because control questions are designed to arouse a subject's concern about their past truthfulness, while relevant questions ask about a crime they know they did not commit. A pattern of greater physiological response to relevant questions than to control questions leads to a diagnosis of "deception." Greater response to control questions leads to a judgment of nondeception. If no difference is found between relevant and control questions, the test result is considered "inconclusive."

An alternative polygraph procedure is called the Guilty Knowledge Test (GKT). A GKT involves developing a multiple-choice test with items concerning knowledge that only a guilty subject could have. A test of a theft suspect might, for example, involve questions such as "Was $500, $1,000, or $5,000 stolen?" If only a guilty suspect knows the correct answer, a larger physiological reaction to a correct choice would indicate deception. With a sufficient number of items, a psychometrically sound evaluation could be developed. GKTs are not widely employed, but there is great interest in doing so. One limitation of the GKT is that it can be used only when investigators have information that only a guilty subject would know. The interpretation of "no deception" is also a potential limitation, since it may indicate lack of knowledge rather than innocence.

The accuracy (i.e., validity) of polygraph testing has long been controversial. An underlying problem is theoretical: There is no evidence that any pattern of physiological reactions is unique to deception. An honest person may be nervous when answering truthfully and a dishonest person may be non-anxious. Also, there are few good studies that validate the ability of polygraph procedures to detect deception. As Dr. Saxe and Israeli psychologist Gershon Ben-Shahar (1999) note, "it may, in fact, be impossible to conduct a proper validity study." In real-world situations, it's very difficult to know what the truth is.

A particular problem is that polygraph research has not separated placebo-like effects (the subject's belief in the efficacy of the procedure) from the actual relationship between deception and their physiological responses. One reason that polygraph tests may appear to be accurate is that subjects who believe that the test works and that they can be detected may confess or will be very anxious when questioned. If this view is correct, the lie detector might be better called a fear detector.

Some confusion about polygraph test accuracy arises because they are used for different purposes, and for each context somewhat different theory and research is applicable. Thus, for example, virtually no research assesses the type of test and procedure used to screen individuals for jobs and security clearances. Most research has focused on specific incident testing. The cumulative research evidence suggests that CQTs detect deception better than chance, but with significant error rates, both of misclassifying innocent subjects (false positives) and failing to detect guilty individuals (false negatives).

Research on the processes involved in CQT polygraph examinations suggests that several examiner, examinee, and situational factors influence test validity, as may the technique used to score polygraph charts. There is little research on the effects of subjects' differences in such factors as education, intelligence, or level of autonomic arousal.

Evidence indicates that strategies used to "beat" polygraph examinations, so-called countermeasures, may be effective. Countermeasures include simple physical movements, psychological interventions (e.g., manipulating subjects' beliefs about the test), and the use of pharmacological agents that alter arousal patterns.

Despite the lack of good research validating polygraph tests, efforts are on-going to develop and assess new approaches. Some work involves use of additional autonomic physiologic indicators, such as cardiac output and skin temperature. Such measures, however, are more specific to deception than polygraph tests. Other researchers, such as Frank Andrew Kozel, MD, have examined functional brain imaging as a measure of deception. Dr. Kozel's research team found that for lying, compared with telling the truth, there is more activation in five brain regions (Kozel et al., 2004). However, the results do not currently support the use of fMRI to detect deception in real world individual cases.

Polygraph testing has generated considerable scientific and public controversy. Most psychologists and other scientists agree that there is little basis for the validity of polygraph tests. Courts, including the United States Supreme Court (cf. U.S. v. Scheffer, 1998 in which Dr.'s Saxe's research on polygraph fallibility was cited), have repeatedly rejected the use of polygraph evidence because of its inherent unreliability. Nevertheless, polygraph testing continues to be used in non-judicial settings, often to screen personnel, but sometimes to try to assess the veracity of suspects and witnesses, and to monitor criminal offenders on probation. Polygraph tests are also sometimes used by individuals seeking to convince others of their innocence and, in a narrow range of circumstances, by private agencies and corporations.

The development of currently used "lie detection" technologies has been based on ideas about physiological functioning but has, for the most part, been independent of systematic psychological research. Early theorists believed that deception required effort and, thus, could be assessed by monitoring physiological changes. But such propositions have not been proven and basic research remains limited on the nature of deceptiveness. Efforts to develop actual tests have always outpaced theory-based basic research. Without a better theoretical understanding of the mechanisms by which deception functions, however, development of a lie detection technology seems highly problematic.

When the numbers have been set, players will take turns asking question's about opponent's password. Then the player taking the question must answer with a lie. If player will say truth, the truth detector will activate and player will have to reveal a number not in their password to the opponent as a penalty.

Players are only allowed to ask questions about the password. When players answer, they may not give an unrelated answer, an impossible answer or an evasive answer. For example, when asked "How many odd numbers are in your password?", an unrelated answer, like "I'm a man!", or an impossible answer like "There are 5", or an evasive answer like "I don't know" is not allowed. If player has 3 odd numbers in the password, they must answer with a lie, for example, "1" or "4".

The player who guesses the opponent's numbers in the correct order using this false information will be the winner. If player figures out opponent's password, they may say answer after calling "answer". However, guessing the password takes a turn.

The user can sense when they are being told the truth by various means. This ability allows the user to constantly sense when information told to them is credibly given by another and whether a person speaking is telling the truth. The ability to control one's own emotions and body changes do not act as a definite limitation for the user as they can sense whether or not a person is speaking the truth without such details.

A polygraph, often incorrectly referred to as a lie detector test,[1][2][3] is a junk science[4][5][6] device or procedure that measures and records several physiological indicators such as blood pressure, pulse, respiration, and skin conductivity while a person is asked and answers a series of questions.[7] The belief underpinning the use of the polygraph is that deceptive answers will produce physiological responses that can be differentiated from those associated with non-deceptive answers; however, there are no specific physiological reactions associated with lying, making it difficult to identify factors that separate those who are lying from those who are telling the truth.[8]

In some countries, polygraphs are used as an interrogation tool with criminal suspects or candidates for sensitive public or private sector employment. Some United States law enforcement and federal government agencies,[9][10] and many police departments use polygraph examinations to interrogate suspects and screen new employees. Within the US federal government, a polygraph examination is also referred to as a psychophysiological detection of deception examination.[11]

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