DISC assessment DISC assessment DISC is a behavior assessment tool based on the DISC theory of psychologist William Moulton Marston, which centers on four different personality traits which are currently Dominance (D), Influence (I), Steadiness (S), and Conscientiousness (C). This theory was then developed into a behavioral assessment tool by industrial psychologist Walter Vernon Clarke. Marston was a lawyer and a psychologist; he also contributed to the first polygraph test, authored self-help books and created the character Wonder Woman. His major contribution to psychology came when he generated the DISC characteristics of emotions and behavior of normal people (at the time, 'normal'
Polygraph device's primary advocate, lobbying for its use in the courts. In 1938 he published a book, "The Lie Detector Test", wherein he documented the theory and use of the device. In 1938 he appeared in advertising by the Gillette company claiming that the polygraph showed Gillette razors were better than the competition. A device recording both blood pressure and breathing was invented in 1921 by John Augustus Larson of the University of California and first applied in law enforcement work by the Berkeley Police Department under its nationally renowned police chief August Vollmer. Further work on this device was done