In 1971, Elias Porter introduced the SDI and Relationship Awareness Theory to the world. His theory focuses on personal strengths and their underlying motivations as the key to understanding people and improving relationships. The SDI is the practical application of the theory and was the first personality assessment to use colors. The SDI has been used on every continent and is available in over 25 languages.
The theory behind the SDI first began to take shape in the 1950s when Elias Porter was part of the team that introduced client-centered therapy and the human potential movement. Porter worked closely with Carl Rogers at the University of Chicago, where he began working with personality assessments and was a contributor Rogers’ client-centered concepts Porter’s earliest assessments were based on Erich Fromm’s descriptions of non-productive personalities, which were an advancement of Sigmund Freud’s concepts.