Brief history
Polygraphic tests have been in existence since the end of the 19th century when an Italian physician, Caesare Lambrosso, invented the first “lie detector” created to measure blood pressure and blood volume of suspects during interrogations. Already in that era, we had established scientific proof that hiding the truth provokes physiological reactions in humans. While less sophisticated than the equipment we use today, the apparatus refined in 1925 by the American physician Leonard Keeler, was measuring the same variables as modern polygraphs, such as pulse, blood pressure, breathing variations, sweat gland activity, etc. Later, researchers developed the first apparatus capable of producing the graphics which reproduce the physical reactions of an individual during interrogation. From that time on, specialists in the interpretation of these graphics were known as polygraphists.
Today, computers allow us to read, infinitely more precisely, the data subjects communicate. Highly reliable analysis software and programs have been so well developed in the United States that polygraphic tests are now used throughout the industrialized world as orientation tools and investigation aids.