Lie detection

Lie detection is an assessment of a verbal statement with the goal to reveal a possible intentional deceit. Lie detection may refer to a cognitive process of detecting deception by evaluating message content as well as non-verbal cues. It also may refer to questioning techniques used along with technology that record physiological functions to ascertain truth and falsehood in response. The latter is commonly used by law enforcement in the United States, but rarely in other countries because it is based on pseudoscience. There are a wide variety of technologies available for this purpose. The most common and long used measure is the polygraph, which the U.S. National Academy of Sciences states, in populations untrained in countermeasures, can discriminate lying from truth telling at rates above chance, though below perfection. They added that the results apply only to specific events and not to screening, where it is assumed that the polygraph works less well. Lie detection is an assessment of a verbal statement with the goal to reveal a possible intentional deceit. Lie detection may refer to a cognitive process of detecting deception by evaluating message content as well as non-verbal cues. It also may refer to questioning techniques used along with technology that record physiological functions to ascertain truth and falsehood in response. The latter is commonly used by law enforcement in the United States, but rarely in other countries because it is based on pseudoscience. There are a wide variety of technologies available for this purpose. The most common and long used measure is the polygraph, which the U.S. National Academy of Sciences states, in populations untrained in countermeasures, can discriminate lying from truth telling at rates above chance, though below perfection. They added that the results apply only to specific events and not to screening, where it is assumed that the polygraph works less well. The cumulative research evidence suggests that machines do detect deception better than chance, but with significant error rates and that strategies used to 'beat' polygraph examinations, so-called countermeasures, may be effective. Despite unreliability, results are admissible in court in some countries such as Japan. Lie detector results are very rarely admitted in evidence in the US courts. In 1983 the U.S. Congress Office of Technology Assessment published a review of the technology and found: In the 2007 peer-reviewed academic article 'Charlatanry in forensic speech science', the authors reviewed 50 years of lie detector research and came to the conclusion that there is no scientific evidence supporting that voice analysis lie detectors actually work. Lie detector manufacturer Nemesysco threatened to sue the academic publisher for libel resulting in removal of the article from online databases. In a letter to the publisher, Nemesysco's lawyers wrote that the authors of the article could be sued for defamation if they wrote on the subject again. Nevertheless, extraneous 'noise' on the polygraph can come from embarrassment or anxiety and not be specific to lying. When subjects are aware of the assessment their resulting emotional response, especially anxiety, can impact the data. Additionally, psychological disorders can cause problems with data as certain disorders can lead a person to make a statement they believe to be truth but is actually a fabrication. As well as with all testing, the examiner can cause biases within the test with their interaction with the subject and interpretation of the data. The study of physiological methods for deception tests measuring emotional disturbances began in the early 1900s. Vittorio Benussi was the first to work on practical deception tests based on physiological changes. He detected changes in inspiration-expiration ratio—findings confirmed by N.E. Burtt. Burtt conducted studies that emphasized the changes in quantitative systolic blood-pressure. William Moulton Marston studied blood-pressure and noted increase in systolic blood pressure of 10 mm Hg or over indicated guilt through using the tycos sphygmomanometer, with which he reported 90–100% accuracy. His studies used students and actual court cases. Then in 1913 W.M. Marston determined systolic blood-pressure by oscillatory methods and his findings cite definite changes in blood pressure during the deception of criminal suspects. In 1921, John Augustus Larson criticized Marston's intermittent blood pressure method because emotional changes were so brief they could be lost. To adjust for this he modified the Erlanger sphygmograph to give a continuous blood pressure and pulse curve and used it to study 4,000 criminals. Two meta-analyses conducted by 2004 found an association between lying and increased pupil size and compressed lips. Liars may stay still more, use fewer hand gestures, and make less eye contact. Liars may take more time to answer questions but on the other hand, if they have had time to prepare, they may answer more quickly than people telling the truth would, and talk less, and repeat phrases more. They do not appear to be more fidgety, blink more, or have a less-relaxed posture. Paul Ekman has used the Facial Action Coding System (FACS) and 'when combined with voice and speech measures, reaches detection accuracy rates of up to 90 percent.' However, there is currently no evidence to support such a claim. It is currently being automated for use in law enforcement and is still being improved to increase accuracy. His studies use micro-expressions, which last less than one-fifth of a second, and 'may leak emotions someone wants to conceal, such as anger or guilt.' However, 'signs of emotion aren't necessarily signs of guilt. An innocent person may be apprehensive and appear guilty,' Ekman reminds us.With regard to his studies, lies about emotions at the moment have the biggest payoff from face and voice cues while lies about beliefs and actions, such as crimes use cues from gestures and words are added. Ekman and his associates have validated many signs of deception, but do not publish all of them as not to educate criminals James Pennebaker uses the method of Linguistic Inquiry and Word Count (LIWC), published by Lawrence Erlbaum, to conduct an analysis of written content. He claims it has accuracy in predicting lying. Pennebaker cites his method as 'significantly more effective than human judges in correctly identifying deceptive or truthful writing samples'; there is a 67% accuracy rate with his method, while trained people have 52% accuracy. There were five experimental procedures used in this study. Study 1–3 asked participants to speak, hand write or type a true or false statement about abortion. The participants were randomly assigned to tell a true or false statement. Study 4 focused on feelings about friends and study 5 had the students involved in a mock crime and asked to lie. Human judges were asked to rate the truthfulness of the 400 communications dealing with abortion. The judges read or watched the statement and gave it a yes or no answer about if this statement was false or not. LIWC correctly classified 67% of the abortion communications and the judges correctly classified 52%. His studies have identified that deception carries three primary written markers. The first is fewer first-person pronouns. Those lying 'avoid statements of ownership, distance themselves from their stories and avoid taking responsibility for their behavior' while also using more negative emotion words such as 'hate, worthless and sad.' Second, they use 'few exclusionary words such as except, but or nor' when 'distinguish what they did from what they did not do.'