Polygraphs

Polygraphs, commonly referred to as lie detectors, are electronic instruments commonly used during pre-employment background investigations and in criminal investigations, although on a more limited basis. The ethical issues pertaining to polygraph use are essentially deception, coercion, and justice. Additionally, for polygraphs to be used ethically, the competency of the examiner and the morality of the investigator using the results are serious matters. This discussion will briefly explain polygraphs and their use, moving to a discussion of ethical issues surrounding their use, and concluding with a brief discussion of means to mitigate ethically questionable practices related to polygraph use.

Lying may be defined as making false or misleading statements for purposes of deception. One may lie to protect one's self or another, one may lie for personal advantage, and one may even lie to be humorous. Lying is generally regarded as unethical, if not sinful, because it destroys trust, the most fundamental basis for all peaceful human interaction. Be that as it may, lying is doubtless as old as civilization and because of the necessity for truth in social relations, it is likely that techniques for detecting lies are as old as lying itself. Although historical techniques for determining veracity doubtless met with some measure of success, most likely as a bluffing tool to coerce what at least appeared as truth, these techniques were of questionable reliability.

Nowhere is there a greater need for truth than in criminal justice operations. Practitioners must be honest people and the success of the justice process is completely dependent on the ability of practitioners to determine the truth in all cases. Perhaps more than any other reason, the development of modern, professional policing drove a perceived need to develop a scientific tool for detecting deception in regard to interrogations of criminal suspects. What was desired was an instrument, the design and operation of which were based in sound science, that would give reliable, accurate assessments of a person's honesty and would not cause harm or rely on undue coercion.

It must be remembered that throughout the 19th and early 20th centuries, what would now be regarded as extreme coercion (for example, beatings, simulated hangings, deprivation of food and sleep) was commonly used to persuade suspects to “come clean” by confessing their guilt to investigating officers. Such methods were not only abusive of basic human rights, but also were often ineffective and generally unreliable. They were certainly not compatible with the rising police professionalism movement of the early 20th century. Scientific advances during the early decades of the 20th century and collaboration between scientists and police agencies led to the development of the modern polygraph in the 1920s and 1930s.

A polygraph is an electrically operated instrument that when properly attached to the subject of an interview measures certain physical responses of that individual during the interview process. Specifically, most polygraph instruments measure heart rate, blood pressure, respiration rate, and “galvanic skin response,” that is, perspiration. The premise is that when one speaks truthfully, there will be little to no measurable change in these physiological processes; when one lies, one's guilt (conscious or not) or apprehension at being caught in a lie triggers a physical reaction beyond the conscious control of the individual. Thus, the polygraph operator may determine through observation of changes of these physiological responses the probability that the subject of the interview is attempting to deceive or is lying outright. This is a critical point in terms of ethics; [Page 679]polygraphs do not detect lies or deception, per se. They merely report physiological changes in the subject of a formal interview. Although it is a matter of objective science that such physiological changes are closely associated with deception, it is the polygraph operator's subjective determination of the likelihood the subject was attempting to deceive through lying, embellishing the truth, or telling only part of the truth. Although the examiner makes this determination using a probability scale based in scientific research, it is still a subjective judgment. After the examiner renders a judgment, it is the responsibility of an investigator to determine how the probability of deception as stated in the examiner's report is to be used toward a given end. Since nothing is definitive, the possibility of abuse is strong.

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