Polygraph
Since the time the polygraph has been introduced, it has been deemed inadmissible by the Courts. The polygraph is essentially an instrument which detects and records measured changes in the human body affected by the activation of the automatic nervous system. Basically, the polygraph does not detect false statements; rather, it measures those psychological responses which we identify as being constant with the subject's fear of detecting deception. The theory which underlies its justification is that the fear of detection will cause a physical change or reaction which will be recorded by the polygraph as the subject attempts to conceal the truth.

With any instrument it is important to make sure that the instrument is used correctly and that the polygraph examiner has experience in questions as well as in responses. The interpretation of the polygraph results is as important as the polygraph itself.

The basic polygraph examination is conducted by dividing the test into a pretesting and post-test phase. In the pretest phase, the polygraph examiner makes notes of such things as demeanor, stress levels, perspiration, eye contact, body language, and verbal comments. The polygraph examiner usually begins by explaining the reason for the polygraph as well as an acknowledgment that the subject understands his rights and releases the examiner from liability.

The test phase begins with a series of questions that usually take approximately two minutes. After those questions are asked, the examiner deflates the blood pressure cuff and examines the tracing chart. Essentially, the examiner is looking for physiological responses that may identify or be consistent with the subject's fear of being caught in a lie. In other words, under these conditions someone trying to deceive the examiner will inadvertently trigger stress or other observable reactions.

The post-test phase includes the difficult decision making of the polygraph examiner. An experienced polygraph examiner is the key to success of a polygraph. A qualified polygraph examiner will be one that has credentials from the American Polygraph Association or other agency that specializes in polygraph training.

The post-test or the diagnostic phase of the polygraph examination will include all the data obtained from the polygraph itself as well as the observation and notes taken in the pre-test and other factors.

The results of the polygraph will be scored:

1. No Deception Indicated
2. Deception May Be Indicated
3. Inconclusive

Can a polygraph test be beaten? Although the writer does not know if a polygraph test can be beaten, there are some general tips that can help a person do better on a polygraph under certain circumstances. One of the first things is to make sure that you try to relax. In other words, the polygraph test is more likely to be passed by an innocent person who is calm and does not get nervous during the examination. Some people indicate that inflicting pain upon yourself or tightening your muscles can help you pass a polygraph. Certainly a person who is taking a sedative or valium may have a better chance of passing a polygraph due to the effect of the drugs on the central nervous system. Also, as a matter of common sense, don't look nervous. In other words, do not tap your fingers or constantly jerk around in your chair. And last but not least, you should always be consistent in your answers while answering the questions during the polygraph test.

A final word on polygraphs. Polygraphs are not admissible in most Courts in the United States. However, there could be arguments made that polygraphs have reached the scientific reliability qualifications concerning expert testimony. Conversely, there is still a great deal of the scientific community that remains extremely suspect of polygraph techniques, examiners and the instrument itself. There still exists today a high probability that the results of a polygraph test may unduly prejudice the jury against one defendant or another, thus raising the question of whether polygraphs should at all ever be considered for admission into evidence.