Theory of mind refers to the ability to understand the nature of the mind, to recognize that people experience the world through their beliefs. The understanding that all people have unique mental perspectives develops gradually across childhood. In the preschool years, children master the concept of false beliefs. In other words, children grasp: that our beliefs are not equal to external reality; that one person’s beliefs can be different from another person’s beliefs and that our beliefs shape our actions. Development of this skill is a critical step in socialization, in the ability to manage interpersonal relationships. People with autism, a psychiatric disorder characterized by interpersonal skills deficits, are believed to lack adequate theory of mind.