Law and Lie Detection Polygraph http://people.howstuffworks.com/lie-detector1.htmhttp://people.howstuffworks.com/lie-detector3.htmFacts: American Polygraph Research- 98% reliability Analog polygraphs Digital polygraphs When you sit down in the chair for a polygraph exam, several tubes and wires are connected to your body in specific locations to monitor your physiological activities. Deceptive behavior is supposed to trigger certain physiological changes that can be detected by a polygraph and a trained examiner, who is sometimes called a forensic psychophysiologist (FP). This examiner is looking for the amount of fluctuation in certainphysiological activities.- Respiratory rate - Two pneumographs, rubber tubes filled with air, are placed around the test subject's chest and abdomen. When the chest or abdominal muscles expand, the air inside the tubes is displaced. In an analog polygraph, the displaced air acts on a bellows, an accordion-like device that contracts when the tubes expand. This bellows is attached to a mechanical arm, which is connected to an ink-filled pen that makes marks on the scrolling paper when the subject takes a breath. A digital polygraph also uses the pneumographs, but employs transducers to convert the energy of the displaced air into electronic signals.- Blood pressure/heart rate - A blood-pressure cuff is placed around the subject's upper arm. Tubing runs from the cuff to the polygraph. As blood pumps through the arm it makes sound; the changes in pressure caused by the sound displace the air in the tubes, which are connected to a bellows, which moves the pen. Again, in digital polygraphs, these signals are converted into electrical signals by transducers.- Galvanic skin resistance (GSR) - This is also called electro-dermal activity, and is basically a measure of the sweat on your fingertips. The finger tips are one of the most porous areas on the body and so are a good place to look for sweat. The idea is that we sweat more when we are placed under stress. Fingerplates, called galvanometers, are attached to two of the subject's fingers. These plates measure the skin's ability to conduct electricity. When the skin is hydrated (as with sweat), it conducts electricity much more easily than when it is dry.Some polygraphs also record arm and leg movements. As the examiner asks questions,signals from the sensors connected to your body are recorded on a single strip of moving paper. Procedure: Pretest - This consists of an interview between the examiner and examinee, where the two individuals get to learn about each other. This may last about one hour. At this point, the examiner gets the examinee's side of the story concerning the events under investigation. While the subject is sitting there answering questions, the examiner also profiles the examinee. The examiner wants to see how the subject responds to questions and processes information. Design questions - The examiner designs questions that are specific to the issue under investigation and reviews these questions with the subject.Asks all questions beforehand- make guilty feel more guilty, make innocent more at ease In-test - The actual exam is given. The examiner asks 10 or 11 questions, only three of four of which are relevant to the issue or crime being investigated. The other questions are control questions. A control question is a very general question, such as "Have you ever stolen anything in your life?" -- a type of question that is so broad that almost no one can honestly respond with a "no." If the person answers "no," the examiner can get an idea of the reaction that the examinee demonstrates when being deceptive. Post-test - The examiner analyzes the data of physiological responses and makes a determination regarding whether the person has been deceptive. If there are significant fluctuations that show up in the results, this may signal that the subject has been deceptive, especially if the person displayed similar responses to a question that was asked repeatedly.http://www.youtube.com/watch?v=pqjMhNGyDyQTips to beating lie-detector test: - Control heart rate and blood pressure during control questions - Think exciting thoughts - Bite tongue/tack in shoe/do math in head SedativesAntiperspirant on fingertipsTacks placed in the shoeBiting tongue, lip or cheek- False positive - The response of a truthful person is determined to be deceptive.- False negative - The response of a deceptive person is determined to be truthful."If we look at laboratory-based studies, false-positive errors occur somewhat more oftenthan false-negative errors," Horvath said.The forensic psychophysiologist has several tasks in performing a polygraph exam:- Setting up the polygraph and preparing the subject being tested- Asking questions- Profiling the test subject- Analyzing and evaluating test dataHow the question is presented can greatly affect the results of a polygraph exam. There are several variables that an FP has to take into consideration, such as cultural and religious beliefs. Some topics may, by their mere mention, cause a specific reaction in the test subject that could be misconstrued as deceptive behavior. The design of the question affects the way the person processes the information and how he or she responds.There are approximately 3,500 polygraph examiners in the United States, 2,000 of which belong to a professional organization, according to Dr. Frank Horvath, a Michigan State University professor of criminal justice and a member of the American Polygraph Association.There is no national regulation regarding training for polygraph examiners. Laws vary from state to state. For example, can buy polygraph and open business in Ohio immediately. Some states also require examiners to be trained. There are many schools around the United States that have been set up to train people to conduct polygraph exams. One ofthese schools is the Axciton International Academy, which was started by Lee. The school is accredited by the American Polygraph Association and certified by the American Association of Police Polygraphists.Here are the steps that students at the Axciton Academy must complete before becoming licensed forensic pyschophysiologists:- Prior to enrolling in the school, students must possess a baccalaureate degree or have five years of investigative experience and an associates degree.- Students must attend and pass a 10-week intensive course. Curriculum includes psychology,