Who’s Telling the Truth? The Evolution of the Polygraph

Most of us associate the polygraph with what we see in movies — a nervous witness sweating and communicating in short, fragmented sentences with eye contact dodging left and right. For those familiar with the test, this scenario is just the tip of the iceberg and reveals one of the biggest misconceptions many have about its purpose.

In this episode, Fred speaks with Don Krapohl, arguably one of the most influential leaders in polygraphy. He shares how the test has evolved since it was first developed 100 years ago to detect theft on campus at the University of Southern California. Their discussion covers the polygraph’s accuracy, how it can be used for evidence, and alternate technologies.

Don’s polygraph career started in the private sector in 1979, conducting testing for attorneys, police departments and commercial firms in St. Louis, Missouri. In 1985 he was recruited by the US government to perform polygraph testing for intelligence and security purposes, and conducted many significant and highly sensitive cases during that time. His work led to, among other advances, a polygraph algorithm now used on most computer polygraphs. He now works as the Director of Education for the National Center for Credibility Assessment. In his career he has authored more than 100 published research papers, general interest pieces, technical articles and book chapters on credibility assessment and related areas.