Book excerpt: What does it mean to be human? Why do we feel and behave in the ways that we do? The classic answer is that we have a special kind of intelligence. But to understand what we are as humans, we also need to know what we are like motivationally. And what is central to this story, what is special about human motivation, is that humans want to share with others their inner experiences about the world--share how they feel, what they believe, and what they want to happen in the future. They want to create a shared reality with others. People have a shared reality together when they experience having in common a feeling about something, a belief about something, or a concern about something. They feel connected to another person or group by knowing that this person or group sees the world the same way that they do--they share what is real about the world. In this work, Dr. Higgins describes how our human motivation for shared reality evolved in our species, and how it develops in our children as shared feelings, shared practices, and shared goals and roles. Shared reality is crucial to what we believe--sharing is believing. It is central to our sense of self, what we strive for and how we strive. It is basic to how we get along with others. It brings us together in fellowship and companionship, but it also tears us apart by creating in-group "bubbles" that conflict with one another. Our shared realities are the best of us, and the worst of us.