The Complete History of the Lie Detector Test: From Origins to Modern Use

The History and Evolution of the Lie Detector Test

People have been telling lies since the development of human consciousness. And for just as long, others have tried to detect deception. Over the centuries, various methods—from chewing rice in ancient China to sophisticated computerized systems—have been developed to uncover the truth. Today’s polygraph machines represent the culmination of thousands of years of efforts to reliably measure physiological signs of dishonesty.

📜 Timeline of Polygraph History

• Ancient China (~1000 BCE): Suspected liars were made to chew rice; dry rice implied guilt due to reduced saliva from stress.

• 1875: Angelo Mosso creates the first scientific instruments to measure deception, such as the plethysmograph.

• 1879: Dr. Marie Vigouroux explores the electrodermal response (skin conductance) to deception.

• 1895: Cesare Lombroso uses pulse and blood pressure changes to identify deception. His hydrosphygmograph becomes the first such device used in court.

• 1914: Vittorio Benussi introduces the pneumograph to track respiration rate as a deception indicator.

• 1921: John Augustus Larson develops the first polygraph instrument measuring blood pressure, pulse, and respiration.

• 1925–1938: Leonard Keeler improves upon Larson’s design, adding ink pens and galvanic skin response measurement.

• 1945–1947: John E. Reid develops the Control Question Technique and the Reid technique of interrogation.

• 1950s–1960s: Polygraph usage expands; Lafayette Instrument Company is founded and begins producing standardized polygraph systems.

• 1980s–1990s: Computer Assisted Polygraph Systems (CAPS) are introduced, increasing automation and reducing examiner bias.

• 2000s–present: Advancements in sensors, digital analytics, and wireless technology refine accuracy and usability.

🧪 Early Origins: Deception Detection Before Science

In ancient China, authorities observed that lying often caused dry mouth due to stress. Suspects chewed dry rice; if it remained dry, they were presumed guilty. This test illustrates one of the earliest connections made between stress and physiology.

In ancient Sparta, warriors evaluated fear in recruits’ voices by placing them near cliff edges—a brutal, pre-scientific assessment of courage and honesty. During the Spanish Inquisition, Catholic interrogators noted pulse increases in the accused when answering truth-seeking questions, laying an early foundation for later medical studies on deception.

🧬 The Scientific Foundation: Mosso and Early Physiologists

Italian physiologist Angelo Mosso (1875) advanced deception detection by linking lying to measurable changes in blood pressure and respiration. His devices, called plethysmographs, were some of the first tools to provide physiological evidence of lying. He concluded that fear and deception triggered involuntary autonomic nervous system responses.

Building on Mosso’s ideas, Dr. Marie Vigouroux (1879) and later Boris Sidis (1909) focused on the skin’s electrical conductance. Their research laid the groundwork for the electrodermal response (GSR)—still measured in today’s polygraphs.

⚖️ From Courtroom to Credibility: Lombroso to Benussi

Criminologist Cesare Lombroso used a sphygmomanometer and plethysmograph to track pulse and blood pressure changes in suspects. In 1902, his methods were used in court to help prove a man’s innocence.

In 1914, Vittorio Benussi introduced respiratory analysis into lie detection. His pneumograph measured the ratio of inhalation to exhalation, which he found changed during deception. His studies were essential in identifying how breathing correlates with lying.

🔬 The Birth of the Modern Polygraph

John Augustus Larson (1921) created the first full polygraph that recorded multiple physiological responses simultaneously. He worked with psychologist William Moulton Marston, who earlier developed blood pressure-based interrogation techniques used during WWI. Larson’s technique—the Relevant/Irrelevant Question method—was an important innovation in early forensic science.

His student, Leonard Keeler, further enhanced the device by adding galvanic skin response and designing a more compact, portable machine. By 1935, Keeler had examined over 2,000 suspects and developed the Keeler Polygraph. He also opened the Keeler Polygraph Institute in 1947—the first of its kind.

🧠 Interrogation Techniques and Modernization

John E. Reid revolutionized polygraph interrogation with the Control Question Technique (CQT). He introduced psychological strategies to improve accuracy, but his methods—particularly the Reid technique—remain controversial due to their potential to elicit false confessions.

Cleve Backster, a CIA examiner, contributed the quantified chart analysis technique, which used numerical scoring to improve objectivity. His methods laid the groundwork for algorithmic analysis used today.

Meanwhile, the Lafayette Instrument Company, founded by Max Wastl in 1947, became the primary manufacturer of professional-grade polygraph equipment. By the 2000s, their systems were used by law enforcement agencies in over 70 countries.

💻 Digital Transformation and the Computer Age

In the 1980s, researchers at the University of Utah introduced Computer-Assisted Polygraph Systems (CAPS). These systems reduced human interpretation errors and set the stage for digital polygraph analysis.

By 1992, most modern polygraphs featured digital sensors and software, enhancing data accuracy and storage. Lafayette’s LX4000-SW, released in 2007, became the first wireless polygraph system, pushing the industry further into the digital realm.

Today, computerized polygraphs use advanced algorithms, sensitive biometric sensors, and proprietary scoring models to evaluate truthfulness more accurately than ever.

🔍 Polygraph Use Today: Benefits and Controversy

Polygraphs are now widely used in:

• Law enforcement (criminal investigations, sex offender monitoring)

• Intelligence and national security (CIA, FBI, MI5)

• Workplace integrity tests (in countries where legally allowed)

• Private matters (infidelity, theft, family disputes)

However, their admissibility in court remains debated. In the U.S., the Employee Polygraph Protection Act (EPPA) of 1988 restricts workplace use. Courts typically require polygraph results to be corroborated by other evidence.

📊 Accuracy: A Point of Contention

• Proponents claim polygraphs are up to 98% accurate under proper conditions.

• Critics argue reliability may be as low as 60–70%, due to countermeasures, examiner bias, or misinterpretation.

Despite the disagreement, the polygraph remains a key investigative tool. Its strength lies in eliciting confessions, rather than being purely evidential.

✅ Final Thoughts

From chewing rice to advanced biometric software, the lie detector has come a long way. Each step in its development—from early observation of fear to digital signal processing—represents society’s unrelenting drive to uncover the truth.

Whether embraced or challenged, the polygraph is a powerful reflection of humanity’s ongoing pursuit of honesty and accountability.