The document discusses how the introduction of psychoanalysis in the early 20th century changed marketing by leading to the creation of market segments based on psychological profiles rather than just demographics. Marketers now use sophisticated psychological techniques revealed by psychoanalysis to motivate consumers and target specific market segments by appealing to irrational wants rather than just rational needs. Key figures like Edward Bernays and Ernest Dichter pioneered using psychology to shape consumer desires and persuade the public, which was believed to support democracy by fueling economic growth.