In psychology, theory of mind refers to the capacity to understand other people by ascribing mental states to them. A theory of mind includes the knowledge that others' beliefs, desires, intentions, emotions, and thoughts may be different from one's own. Possessing a functional theory of mind is considered crucial for success in everyday human social interactions. People utilise a theory of mind when analyzing, judging, and inferring others' behaviors. The discovery and development of theory of mind primarily came from studies done with animals and infants. Factors including drug and alcohol consumption, language development, cognitive delays, age, and culture can affect a person's capacity to display theory of mind. Having a theory of mind is similar to but not identical with having the capacity for empathy or sympathy.
It has been proposed that deficits in theory of mind can occur in people with autism, anorexia nervosa, schizophrenia, dysphoria, attention deficit hyperactivity disorder, cocaine addiction, and brain damage caused by alcohol's neurotoxicity. Neuroimaging shows that the medial prefrontal cortex (mPFC), the posterior superior temporal sulcus (pSTS), the precuneus, and the amygdala are associated with theory of mind tasks. Patients with frontal lobe or temporoparietal junction lesions find some theory of mind tasks difficult. One's theory of mind develops in childhood as the prefrontal cortex develops. It has been argued that children in a culture of collectivism develop knowledge access earlier and understand diverse beliefs later than Western children in a culture of individualism.
A theory of mind is described as a "theory" because the behavior of the other person, such as their statements and expressions, is the only thing being directly observed; no one has direct access to the mind of another, and the existence and nature of the mind must be inferred. It is typically assumed that others have minds analogous to one's own; this assumption is based on reciprocal social interaction, as observed in joint attention, the functional use of language, and the understanding of others' emotions and actions.