DISC Theory
In the early 1920's, an American psychologist named William Moulton Marston developed a theory to explain people’s emotional responses. Until that time, work of this kind had been mainly confined to the mentally ill. Marston wanted to extend these ideas to cover the personalities of ordinary individuals.
In order to test his theories, Marston needed some way of measuring the personalities he was trying to describe. His solution was to develop his own personality test to measure four important personality factors. The factors he chose were Dominance, Influence, Steadiness and Conscientious, from which the DISC assessment takes its name.
In 1926, Marston published his findings in a book entitled The Emotions of Normal People, which included a brief description of the personality test he had developed. From these humble beginnings, the DISC test has grown to become probably the most widely used personality assessment tool in the world.