Role-playing refers to the changing of one's behaviour to assume a role, either unconsciously to fill a social role, or consciously to act out an adopted role. While the Oxford English Dictionary offers a definition of role-playing as "the changing of one's behaviour to fulfill a social role", in the field of psychology, the term is used more loosely in four senses:
Many children participate in a form of role-playing known as make believe, wherein they adopt certain roles such as doctor and act out those roles in character. Sometimes make believe adopts an oppositional nature, resulting in games such as cops and robbers.