The Traces of Emotions
This chapter focuses on using suspects’ subtle emotional displays as an indication of their veracity. Münsterberg mentions several physiological indicators of an unconscious emotional reaction, such as changes in pulse, breathing, and galvanic skin response. The sorts of physiological measures described by Münsterberg foreshadow the polygraph, which relies on just such measures. The polygraph has been controversial since its inception and continues to be held in lower esteem by the scientific community than by law enforcement. The present chapter reviews psychological research on the polygraph as a lie detection tool. More specifically, it traces the history and uses of lie detectors, up to the most current methodologies. The chapter reviews the advantages and limitations of the various techniques used by polygraphers to establish the truth or deceptiveness of statements. Finally, the chapter discusses the history of the legal status of the polygraph.