Psychology in Business

Lie Detection: The Science and Development of the Polygraph

By Katherine To

The idea of using a polygraph for lie detection emerged at the end of the nineteenth century. Despite major technological advances in the twentieth century, the polygraph has evolved little since its invention. The polygraph works under the assumption that lies can be detected by certain measurable physiological changes, a theory proposed more than 100 years ago. The three physiological vectors measured in polygraphs in the 1920s cardiovascular, respiratory and perspiratory activities are still measured by modern polygraphs. Although the polygraph is still widely used, critics question its accuracy because of the subjectivity involved in the test. Recent technological breakthroughs have created new machines for lie detection. However, since many of these new technologies still operate under questionable assumptions, they are still prone to error and misinterpretation.

Introduction

You are seated in a room, alone with an examiner. The examiner hooks wires and straps to your body. You are nervous and your heart begins to pound. He starts asking you questions. You try to stay calm, since you are innocent and have nothing to conceal. However, agonizingly, you feel your hands sweat, as you worry that the metal box and computer next to you will devastate your future.

This is one possible reaction that a test subject might have to the type of polygraph tests that are conducted throughout the nation every year. Although polygraph tests are inadmissible as evidence in most states, polygraphs are administered to many witnesses and suspects to streamline police investigations and project new directions of examinations. Over 20 federal agencies use polygraphs to screen job applicants and current employees [1]. Occasionally, polygraphs make their way to the news headlines and provoke heated debate. For example, when California Congressman Gary Condit was involved in the scandal of missing intern...