First of all, modern propaganda is based on scientific analyses of psychology and sociology. Step by step, the propagandist builds his techniques on the basis of his knowledge of man, his tendencies, his desires, his needs, his psychic mechanisms, his conditioning - and as much on social psychology as on depth psychology. He shapes his procedures on the basis of our knowledge of groups and their laws of formation and dissolution, of mass influences, and of environmental limitations. Without the scientific research of modern psychology and sociology there would be no propaganda, or rather we still would be in the primitive stages of propaganda that existed in the time of Pericles or Augustus.