Voice Stress Analysis
The most common and widely known form of lie detection uses a polygraph instrument. Although such detection is controversial for a number of reasons, even its most adamant proponents would acknowledge that it has limitations. The first limitation is that, because there is no known physiological response unique to “lying,” the polygraph instrument does not really detect “lies”; it merely records physiological data that vary when one undergoes stress, such as the stress that accompanies lying. Thus, the person who administers the examination and interprets the physiological data must be well trained and must assess the physiological information accurately after it is collected in a manner consistent with accepted procedures in order for “lie detection” to work. That is, the process must be properly applied, and the instrument used must be capable of detecting stress. The polygraph, thus, can be seen merely as a “stress detector,” a collector of physiological ...