The polygraph, often portrayed as a magic mind-reading machine, is still controversial among experts, who continue heated debates about its validity as a lie-detecting device. As the nation takes a fresh look at ways to enhance its security, can the polygraph be considered a useful tool? The Polygraph and Lie Detection puts the polygraph itself to the test, reviewing and analyzing data about its use in criminal investigation, employment screening, and counter-intelligence. The book looks at: The theory of how the polygraph works and evidence about how deceptivenessâ€"and other psychological conditionsâ€"affect the physiological responses that the polygraph measures. Empirical evidence on the performance of the polygraph and the success of subjects' countermeasures. The actual use of the polygraph in the arena of national security, including its role in deterring threats to security. The book addresses the difficulties of measuring polygraph accuracy, the usefulness of the technique for aiding interrogation and for deterrence, and includes potential alternativesâ€"such as voice-stress analysis and brain measurement techniques.

In this fascinating history of the lie detector, Ken Alder exposes some persistent truths about our culture: why we long to know the secret thoughts of our fellow citizens; why we believe in popular science; and why we embrace ?truthiness.? For centuries people searched in vain for a way to unmask liars, seeking clues in the body?s outward signs: in blushing cheeks and shifty eyes. Not until the 1920s did a cop with a PhD team up with an entrepreneurial high school student and claim to have invented a foolproof machine capable of peering directly into the human heart. Scientists repudiated the technique, and judges banned its results from criminal trials, but in a few years their polygraph had transformed police work, seized headlines, and enthralled the nation.ø In this book, Alder explains why America?and only America?has embraced this mechanical method of reading the human soul. Over the course of the twentieth century, the lie detector became integral to our justice system, employment markets, and national security apparatus, transforming each into a game of bluff and bluster. The lie detector device may not reliably read the human mind, but this lively account shows that the instrument?s history offers a unique window into the American soul.