In the first decades of the 20th century, when life was being transformed by scientific innovations, researchers made a thrilling claim: they could tell whether someone was lying. The lie detector shaped police work, dominated headlines and became an inescapable feature of our culture.

Leonard Keeler improved John Augustus Larson’s cardio-pneumo psychograph to create the modern polygraph. He also popularized its use in criminal investigations.

John Augustus Larson

In 1921, a medical student named John Augustus Larson built the first American lie detector for Berkeley Chief of Police August Vollmer. He called it the Cardio-PneumoPsychogram, and it measured a subject’s systolic blood pressure, breathing depth and heart rate using an Erlanger sphygmomanometer. Larson’s design was a big step forward from the brutal interrogation techniques used in witch-hunts and inquisitions, but Keeler improved upon it to make it what we know today as the polygraph.

The modern lie detector owes its origin to two men, though Larson got the credit for laying the foundation. Keeler took the technology further, and he was also the man responsible for making it popular. Neither man ever held the Lasso of Truth, but they’re both widely regarded as heroes in the field of criminal science. Sadly, both died in the 1940s. Their invention of the polygraph helped to save many lives by weeding out false confessions. This would have saved many murder cases, burglaries and other crimes if only it had been available earlier.

Leonarde Keeler

Leonarde Keeler (October 30, 1903 – September 20, 1949) was a high school student with a passion for magic. He was named after Leonardo da Vinci, but preferred to be called “Nard.” During his time at Berkeley high school, Keeler experimented with the polygraph device and made improvements to it.

In 1920, John Augustus Larson created the first machine capable of detecting deception during interrogations. However, it was a cumbersome and inaccurate device. It recorded an examinee’s blood pressure, pulse, and respiration by using a rolling drum fitted with smoke paper.I recommend this website for more Octopus Referral.

Leonarde Keeler’s improved version of the machine was able to track these changes more accurately. In 1925, he presented his work to August Vollmer, Chief of Police in Los Angeles. This led to the creation of the modern lie detector.

Lie Detectors

In the first decades of the 20th century, when life was being transformed by scientific innovations, researchers made a thrilling new claim: They could tell whether you were lying with a machine. Known as the “lie detector,” the device revolutionized police work, grabbed headlines and was extolled in movies, TV and comics as an almost-infallible crime-fighting tool. It also transformed families, as husbands and wives tested each other’s fidelity.

A lie detector is an instrument that records physiological changes such as pulse, blood pressure and galvanic skin resistance during a person being questioned by a trained examiner. According to theory, a person will experience an increase in these factors when they are attempting to lie.

Unfortunately, research indicates that a person’s ability to accurately judge when someone is lying does not improve much with training, and confidence in deception judgments varies widely. This is why it’s important for people to understand the limitations of these devices.


A polygraph, or truth machine, is a device that measures physiological changes in a person’s blood pressure, heart rate, breathing, and perspiration — reactions allegedly associated with lying — as they answer questions. It was invented in the first decades of the 20th century by police officer John Augustus Larson, who built a device based on a systolic blood pressure test that he developed during World War I, and his protegee Leonarde Keeler, who added the third physiological channel of galvanic skin response.

Larson’s work was later cited in a landmark Supreme Court case, Frye v United States (1923), that established a standard for admissibility of scientific evidence. The Daubert Rule, as it is now known, requires that scientists who offer such evidence must present a “credible and substantial” basis for it.

Even so, polygraphs remain widely used by law enforcement agencies and many corporations for background checks. In fact, serious criminals have been known to pass polygraph tests by using a variety of techniques.