Theory of mind is the ability to attribute mental states such as beliefs, intents, desires, and knowledge, to oneself and others and to understand that others have beliefs, desires and intentions that are different from one’s own. It is a theory insofar as the mind is not directly observable. The presumption that others have a mind is termed a “theory of mind” because each human can only prove the existence of his or her own mind through introspection, and one has no direct access to others’ minds.
It is typically assumed that others have minds by analogy with one’s own, and based on the reciprocal nature of social interaction, the functional use of language, and understanding of others’ emotions and actions. Having a theory of mind allows one to attribute thoughts, desires, and intentions to others, to predict or explain their actions, and to posit their intentions. As originally defined, it enables one to understand that mental states can be the cause of others’ behavior.
Theory of mind appears to be an innate potential ability in humans, but one requiring social and other experience over many years to bring to fruition. Different people may develop more, or less, effective theories of mind. Empathy is a related concept, meaning experientially recognizing and understanding the states of mind, including beliefs, desires and particularly emotions of others, often characterized as the ability to “put oneself into another’s shoes.”
Research on theory of mind in a number of different populations has grown rapidly in the almost 30 years since Premack and Woodruff’s paper Does the chimpanzee have a theory of mind?, as have the theories of theory of mind. The emerging field of social neuroscience has also begun to address this debate, by imaging humans while performing tasks demanding the understanding of an intention, belief, or other mental state.