Theory of Mind

Theory of mind is the ability of individuals to understand their own and others’ mental states—such as beliefs, thoughts, emotions, intentions, and desires—and to use this knowledge to interpret or predict behavior. This capacity requires individuals to acknowledge that other minds may hold perspectives different from their own and to comprehend how these mental states manifest in behavior. Through this, individuals generate abstract representations of mental states and apply them within social contexts. This skill is one of the foundational building blocks of advanced social cognition unique to humans and plays a critical role in higher-order social functions such as empathy, deception, cooperation, and complex communication. Theory of mind occupies a central position in social cognition and is studied across diverse disciplines including psychiatry, neuroscience, developmental psychology, and educational sciences. It is regarded as a fundamental component of healthy social interaction and communication.

Theoretical Background

The concept of theory of mind was first introduced into the literature through experimental work by Premack and Woodruff (1978) on primates. In this study, researchers questioned whether chimpanzees could understand the intentions of others and theoretically defined the capacity to be aware of another mind. In subsequent years, this concept has been addressed through various theoretical models in both developmental psychology and cognitive neuroscience.

Frith and Frith (2004) define theory of mind not only as a cognitive ability but also as a neuropsychological function associated with specific brain regions. Research has demonstrated that areas such as the medial prefrontal cortex, the temporo-parietal junction, and the posterior superior temporal sulcus are active during theory of mind processes.

Developmental Process

The development of theory of mind proceeds in parallel with maturation of children’s cognitive and social capacities. Research indicates that children typically begin to understand that others may hold beliefs different from their own around the age of four. At this stage, children start to succeed in experimental tasks such as “false belief” tests. However, significant individual differences in development are evident. Numerous factors—including family conversations, presence of siblings, socioeconomic environment, cultural norms, and individual cognitive differences—can influence this development.

Theory of mind skills generally show substantial development during early childhood, particularly within the first six years. The developmental process is divided into two stages:

• First-order theory of mind: Involves basic understanding of others’ mental states directly (e.g., “What is he thinking?”).
• Second-order theory of mind: Reflects more complex social cognition and involves understanding what one person thinks about another’s mental state (e.g., “What does he think she believes?”).

The maturation of these skills during middle childhood is vital for social competence and interpersonal relationships. Theory of mind serves as a critical mechanism for interpreting social behavior and generating appropriate social responses.

Neurobiological Foundations

The neurobiological underpinnings of theory of mind shed light on how social cognitive processes are distributed in the brain. This ability is supported by the interaction of various brain regions and networks. Neuroimaging studies have revealed increased neural activity in specific cortical and subcortical areas when individuals perform tasks requiring theory of mind.

The primary neuroanatomical structures associated with theory of mind are as follows:

• Mirror Neuron System: Located particularly in the inferior frontal gyrus and inferior parietal lobule, this system facilitates understanding of others’ behaviors through observation. Mirror neurons are thought to play a crucial role in comprehending others’ actions and intentions. This system contributes to the “like-me” representations that form the basis of theory of mind.
• Limbic and Paralimbic Structures: Structures such as the amygdala, anterior cingulate cortex, and insula are involved in processing social and emotional stimuli. These regions influence the formation of empathetic responses and the understanding of others’ emotional states. The evaluation of emotional content in social contexts constitutes the affective component of theory of mind processes.
• Medial Prefrontal Cortex (mPFC): Is associated with representing mental states attributed to oneself and others. The mPFC has been shown to be particularly active when making inferences based on abstract social information.
• Temporo-Parietal Junction (TPJ): Is linked to directing attention toward others’ mental content, distinguishing between different perspectives, and performing tasks such as false belief. The TPJ has consistently been shown to activate during mentalizing tasks.
• Posterior Superior Temporal Sulcus (pSTS): Plays a role in interpreting social cues such as eye movements, facial expressions, and movement intentions. This structure contributes indirectly to theory of mind processes.

These structures work in an integrated manner to perceive, interpret, and apply mental states within social contexts. Neuroimaging studies have demonstrated activation in these regions during theory of mind tasks. These systems not only represent mental content but also enable its processing to guide social behavior. Functional disruptions in these regions have been proposed to underlie deficits in theory of mind performance in conditions such as autism spectrum disorder.

Theory of Mind and Neurodevelopmental Disorders

Impairments in theory of mind skills are prominently observed in neurodevelopmental conditions such as autism spectrum disorder (ASD). ASD is one of the most intensively studied areas in theory of mind research. Individuals diagnosed with ASD show significant difficulties in classic theory of mind tasks such as false belief, indicating an inadequacy in forming representations of others’ mental states. This deficit is directly associated with impairments in social interaction—including lack of eye contact, difficulty interpreting gestures and facial expressions, and reduced empathy. Neuroimaging studies have revealed atypical activation patterns in brain regions associated with theory of mind, such as the medial prefrontal cortex, superior temporal sulcus, and temporo-parietal junction, in individuals with ASD. Difficulties in social communication and interaction in these conditions are frequently attributed to deficits in theory of mind. Additionally, impairments in theory of mind functions have also been reported in other psychiatric conditions such as schizophrenia. These findings demonstrate the direct impact of theory of mind skills on social functioning.

Regarding other neurodevelopmental disorders, individuals with attention deficit hyperactivity disorder (ADHD) generally show less pronounced theory of mind impairments compared to those with ASD, but difficulties have been reported in tasks requiring emotional theory of mind. These challenges may stem from executive function deficits such as poor impulse control, planning, and sustained attention. Similarly, in intellectual disability, performance on theory of mind tasks may be reduced, though this may reflect not only general cognitive limitations but also specific deficits in theory of mind itself. Understanding how theory of mind impairments manifest across different neurodevelopmental disorders provides a holistic perspective on the developmental neurobiological foundations of social cognition and offers theoretical grounding for interventions. In particular, evaluating theory of mind as a central component of social cognition in disorders such as autism is crucial for diagnostic processes and intervention approaches.

Individual Differences and Cognitive Foundations

The development of theory of mind varies across individuals and is influenced by various environmental factors. Opportunities for social interaction, frequency of parental use of language referring to mental states, having siblings, and play-based social experiences play significant roles in this development. Moreover, cultural context has been shown to affect the meaning attributed to mental states and to influence the rate of theory of mind development across different cultural groups.

Individual differences in theory of mind skills are closely related to cognitive processes such as language development, working memory, and executive functions. Language skills, in particular, emerge as a decisive factor in the development of theory of mind. Executive functions are necessary for organizing mental states and enabling flexible thinking. The development of these cognitive abilities directly influences theory of mind performance. Research has shown that understanding these relationships can guide early interventions and educational programs.

Social Interaction and Theory of Mind

Theory of mind is a fundamental requirement for mutual understanding and empathy in social interactions. Accurately representing and comprehending one’s own and others’ mental states—such as beliefs, intentions, and emotions—enables individuals to exhibit appropriate behaviors within social contexts. In the process of social interaction, not only verbal expressions but also nonverbal communication forms such as gestures, facial expressions, and tone of voice are used to infer meaning. This process is supported by social skills such as empathy and adherence to social norms. The perception of social context and cultural norms are key factors determining the effectiveness of social interaction. Thus, the development of theory of mind plays a central role in enabling individuals to adapt to their social environments and forms the foundation of social adaptation.