Detection of deception: Its application to forensic psychiatry.

The detection of deception, or "lie detection," as it is commonly referred to, has traditionally been a police investigative tool. More recently, however, the use of lie detection has expanded into the medical, legal and private business sectors at an ever-increasing rate. l More and more allied health pro.fessionals are utilizing the potential of the detection of deception in novel and useful ways. In general and forensic psychiatry, however, the application of lie detection methods to their needs has not been so dramatic. The rather slow growth of this technique in forensic psychiatry may be attributable to a reluctance by mental health professionals to view the detection of deception in any other light than as a police aid. 2 Many professionals fail to see the need or the potential of lie detection in a forensic assessment milieu. Furthermore, traditional definitions and conceptions of usage have limited its application to such a field. In addition, the general population has been given the overall impression, through the media and various other sources, that lie detection is a pseudoscience, a kind of mild interrogation procedure with little merit outside of police work. In part, this is a justifiable criticism, since lie detection has progressed in a rather backward fashion. That is to say, rather than being firmly entrenched in scientifically based theory and then developing a practical technique, the detection of deception has developed a technique first and is just recently attempting empirical validation. Although criticisms of this sort are somewhat justified, progressive application of such a technique in many fields should not be restrained, due to a lack of understanding of its present function. Lie detection encompasses basically two major equipment systems.3 The first and most traditional is the polygraph, which generally, but not always, monitors respiratio\l, cardio-vascular activity and electrodermal activity by the use of attached body sensors.4 The second major equipment system in use today, the voice stress analyzer (VSA), is a relatively new addition.s Although there are several types of VSA's on the market, they are all designed to measure stress resulting from the monitoring of vocal activity, without the need for attached polygraph sensors. Lie detection without sensors would eliminate the confounding variable of sensor-induced artificial arousal. 6 The elimination of sensors, and hence the reduction of subject