Theory of mind is a theory insofar as the behavior of the other person, such as their statements and expressions, is the only thing being directly observed. The mind and its contents cannot be observed directly, so the existence and nature of the mind must be inferred.[8] The presumption that others have a mind is termed a theory of mind because each human can only intuit the existence of their own mind through introspection, and no one has direct access to the mind of another so its existence and how it works can only be inferred from observations of others. It is typically assumed that others have minds analogous to one's own, and this assumption is based on the reciprocal, social interaction, as observed in joint attention,[9] the functional use of language,[10] and the understanding of others' emotions and actions.[11] Having 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—and thus be used to explain and predict—the behavior of others.[8] Being able to attribute mental states to others and understanding them as causes of behavior implies, in part, that one must be able to conceive of the mind as a "generator of representations".[12][13][14] If a person does not have a complete theory of mind, it may be a sign of cognitive or developmental impairment.
Theory of mind appears to be an innate potential ability in humans that requires social and other experience over many years for its full development. Different people may develop more, or less, effective theory of mind. Neo-Piagetian theories of cognitive development maintain that theory of mind is a byproduct of a broader hypercognitive ability of the human mind to register, monitor, and represent its own functioning.[15]
Empathy is a related concept, meaning the recognition and understanding of the states of mind of others, including their beliefs, desires and particularly emotions. This is often characterized as the ability to "put oneself into another's shoes". Recent neuro-ethological studies of animal behaviour suggest that even rodents may exhibit ethical or empathetic abilities.[16] While empathy is known as emotional perspective-taking, theory of mind is defined as cognitive perspective-taking.[17]
Research on theory of mind, in humans and animals, adults and children, normally and atypically developing, has grown rapidly in the years since Premack and Guy Woodruff's 1978 paper, "Does the chimpanzee have a theory of mind?".[8] The field of social neuroscience has also begun to address this debate by imaging the brains of humans while they perform tasks demanding the understanding of an intention, belief or other mental state in others.
An alternative account of theory of mind is given within operant psychology and provides significant empirical evidence for a functional account of both perspective-taking and empathy. The most developed operant approach is founded on research on derived relational responding and is subsumed within what is called relational frame theory. According to this view, empathy and perspective-taking comprise a complex set of derived relational abilities based on learning to discriminate and respond verbally to ever more complex relations between self, others, place, and time, and through established relations.[18][19][20]
