As a leader, psychology is fundamental to your success - whether that means understanding consumer behavior, team dynamics, or even your own biases and blind spots. Harvard professor Steven Pinker says that an important phenomena to understand is that of common knowledge and its downstream effects. It's the idea that there is power in knowledge, but also power in knowing what other people know - and that when a large group of people know what others around them know, and vice versa, that's when major change can happen. He explains how common knowledge underlies meme stocks, the rise of crypto, meeting etiquette and the success of Super Bowl ads. Pinker wrote the new book When Everyone Knows That Everyone Knows . . .: Common Knowledge and the Mysteries of Money, Power, and Everyday Life.