Lie Detector

By: Cici Ryan


Angelo Mosso, an Italian Physiologist, Mosso used an instrument called an plethysmograph in his research. It measured waves in a person's blood pressure.


Cardiologist Sir James Mackenzie develops the first clinical lie detector.
Big image


Italian Physician, Psychologist, and Criminologist Cesare Lombroso was the first person to use the hydrosphygmograph to measure a crime suspects blood pressure and pulse rate to identify dishonesty.


Sir James Mackenzie improves his lie detector to record results with ink and paper.


An American Attorney and Psychologist, Dr. William Moulton Marston, invented an early form of the lie detector using a standard blood pressure cuff and a stethoscope.
Big image


John A. Larson, a Canadian psychologist who worked for the Berkeley Police Dept., created what most consider to be the original lie detector when he added the component that measures respiratory rate along with the blood pressure. It was this instrument that was first called polygraph.


The Polygraph was invented at this time after the Lie Detector. The Polygraph was used to measure the difference in the way that someone was breathing, sweating, and blood pressure. They also made a Psychological Stress Elevator to measure the voice frequency from recordings.


Leonarde Keeler patented what is now understood as the prototype of the modern polygraph — the Keeler Polygraph. Today, Leonarde Keeler is known as the father of polygraph.(GPE)

Late 1970's

Dr. Joseph F. Kubis, of Fordham University in New York City, was the first researcher to use computer applications to analyse polygraph results.
Big image


Department of Energy Polygraph Program was established in 1999. A year later the program was expanded. They are used in investigations.
Big image


Jesse Rissman showed the fMRI scans can reveal if someone thought they had seen someone else before. The scans will not pick up something someone has forgotten.
Big image


Journal of Electrical, Electronics and Computer Engineering (IJEECE) foun that stress affects the voice so people can tell if they are lying.
Big image

How The Lie Detector Works

When a person lies it puts a certain amount of stress on their body that causes the lie detector to react. When you lie your body changes in temperature, blood pressure, breathing, sweat, and pulse. During a polygraph test four to six sensors are attached to the person's body. The person giving the test asks multiple questions. The sensors usually record how the person is breathing, their pulse, blood pressure, and how much they sweat. The test usually takes two to three hours.