Explore every type of lie detector machine from Mackenzie's 1902 polygraph to Keeler instruments, computerized systems, voice stress analyzers, and AI-powered AVATAR.
Read Article →Lynn Marcy graduated from the Keeler Polygraph Institute in 1956, founded the AIPT in 1973, and shaped polygraph examiner training standards for nearly 50…
Read Article →How Clarence Darrow challenged early lie detection technology in Chicago and shaped a century of polygraph admissibility debates in American courts.
Read Article →Explore the decades-long feud between John Larson and Leonarde Keeler over who truly invented the modern polygraph, from Berkeley PD to Northwestern University.
Read Article →Explore how Leonarde Keeler transformed the polygraph from a lab curiosity into a professional industry during his decade at Northwestern's pioneering crime lab (1930–1940).
Read Article →Discover how competing factions of polygraph examiners clashed over training, ethics, and technique standards to create the APA in 1966.
Read Article →Complete history of the Stoelting Deceptograph polygraph — from the 1935 Cardio-Pneumo to the CPSpro digital era. Every model, innovation, and milestone.
Read Article →Complete guide to the Keeler Polygraph Model 302 — the iconic instrument that defined American lie detection from the 1950s through the Cold War…
Read Article →How Leonarde Keeler built the first commercial polygraph practice at Northwestern's crime lab, transforming lie detection into a mainstream forensic tool.
Read Article →Explore the 1930s Keeler era — polygraph commercialization, Northwestern's crime lab, the 1935 Portage trial, and the GSR channel that shaped modern testing.
Read Article →Complete history of Keeler Polygraph instruments from the 1931 patent through 1970s production. Models, specs, serial numbers, and collector values.
Read Article →Leonarde Keeler (1903-1949) transformed the polygraph from a lab curiosity into a portable forensic tool, filing the first U.S. polygraph patent and founding America's…
Read Article →Discover how Leonarde Keeler's Emotograph revolutionized lie detection in the 1920s, replacing cumbersome smoked-paper polygraphs with a portable ink-pen system.
Read Article →US Patent No. 1,788,434 granted to Leonarde Keeler on January 13, 1931, became the first patented lie detection device and launched the modern polygraph…
Read Article →Learn why the NSA, FBI, and CIA require polygraph tests for all personnel — from pre-employment screening to counterintelligence investigations and AI-powered future systems.
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