to the diagnostic accuracy of polygraph testing, even with advances in measurement and scoring techniques. Polygraph accuracy may be reaching a point of diminishing returns. There is only limited room to improve the detection of deception from the physiological responses the polygraph measures.
Although the basic science indicates that polygraph testing has inherent limits regarding its potential accuracy, it is possible for a test with such limits to attain sufficient accuracy to be useful in practical situations, and it is possible to improve accuracy within the test’s inherent limits. These possibilities must be examined empirically with regard to particular applications. We examine the evidence on polygraph test performance in Chapters 4 and 5.
The bulk of polygraph research can accurately be characterized as atheoretical. The field includes little or no research on a variety of variables and mechanisms that link deception or other phenomena to the physiological responses measured in polygraph tests.
Research on the polygraph has not progressed over time in the manner of a typical scientific field. Polygraph research has failed to build and refine its theoretical base, has proceeded in relative isolation from related fields of basic science, and has not made use of many conceptual, theoretical, and technological advances in basic science that are relevant to the physiological detection of deception. As a consequence, the field has not accumulated knowledge over time or strengthened its scientific underpinnings in any significant manner.
There has been no serious effort in the U.S. government to develop the scientific base for the psychophysiological detection of deception by the polygraph or any other technique, even though criticisms of the polygraph’s scientific foundation have been raised prominently for decades. The reason for this failure is primarily structural. Because polygraph and other related research is managed and supported by national security and law enforcement agencies that do not operate in a culture of science to meet their needs for detecting deception and that also believe in and are committed to the polygraph, this research is not structured within these agencies to give basic science its appropriate place in the development of techniques for the physiological detection of deception.