Bloomberg Opinion columnist Barry Ritholtz interviews Dr. Robert Cialdini, professor emeritus of psychology and marketing at Arizona State University and an expert in the fields of persuasion, compliance and negotiation. His book "Influence: Science and Practice" has sold 3 million copies in more than 30 languages; his most recent work, "Pre-Suasion: A Revolutionary Way to Influence and Persuade," is a Wall Street Journal and a New York Times bestseller. Cialdini is also the CEO and president of Influence at Work, which provides training and certification.