Theory of Mind and Neurodevelopmental Disorders of Childhood
Research Article From: Pediatric Research (2011) 69, 101R–108R; doi:10.1203/PDR.0b013e318212c177
By: Baris Korkmaz
To a large extent, the human infant is socialized through the acquisition of a specific cognitive mechanism known as theory of mind (ToM), a term which is currently used to explain a related set of intellectual abilities that enable us to understand that others have beliefs, desires, plans, hopes, information, and intentions that may differ from our own. Various neurodevelopmental disorders, such as autism spectrum disorders, attention deficit hyperactivity disorder, developmental language disorders, and schizophrenia, as well as acquired disorders of the right brain (and traumatic brain injury) impair ToM. ToM is a composite function, which involves memory, joint attention, complex perceptual recognition (such as face and gaze processing), language, executive functions (such as tracking of intentions and goals and moral reasoning), emotion processing-recognition, empathy, and imitation. Hence, ToM development is dependent on the maturation of several brain systems and is shaped by parenting, social relations, training, and education; thus, it is an example of the dense interaction that occurs between brain development and (social) environment.
Abbreviations: ADHD, attention deficit hyperactivity disorder; ASD, autism spectrum disorder; EF, executive functions; MPFC, medial prefrontal cortex; ToM, theory of mind
Human beings continuously make inferences about the psychological states of others. Each of us is constantly analyzing our impressions of others and constructing theories on the basis of the cues and information we receive. This enables us to understand ourselves and others and is a key determinant of self-organization and affect regulation. In addition to “verbal” descriptions of people and observation of their actions, the individual seeks deeper, more psychologically meaningful understandings and attributions in a causal framework to explain and to predict others’ behavior on the basis of internal mental states (1). This kind of theory construction that makes up the core of everyday (folk) psychology is known as Theory of Mind (ToM), a term originating from a study of chimpanzee behavior (2), but entails verbal and conceptual abilities.
ToM, mindreading in everyday parlance (3), is one of the subcomponents of social cognition, which embraces all the skills required to manage social communication and relationships in humans and nonhumans. It develops on the basis of certain mentalizing mechanisms and cognitive abilities and gives rise to the awareness that others have a mind with various mental states including beliefs, intuitions, plans, emotions, information, desires, and intentions and that these may differ from one’s own. Impairment of ToM ability is often seen in children with autism, even in cases with a normal or high level of intelligence and other cognitive abilities (4).
ToM develops fully only in human beings; the presence of a rudimentary ToM in some nonhuman primates and other animals is arguable although they can show very complex social behavior (5). The evolution of ToM probably depends on the increased size of the neocortex and increased importance of vision in primates as well as human beings’ complex forms of social organization (6).
Developmental Precursors of ToM
Normally developing children attain ToM at roughly 3–4 y through a progression of stages starting at around 18 mo with the awareness that their own mental states are distinct from those of others (4,5,7).
The precursors of ToM development include forms of nonverbal communication and gnostic functions that begin to function at birth, for example, physical and emotional contact between mother and child involving reciprocity, engagement, empathy, and imitation. Empathy refers to intuitive and emotional awareness of others’ feelings, the consequence of which is identification and compassion. While empathy is an emotional reaction that is appropriate to another person’s mental state, ToM is a more complex cognitive ability, one of whose components is grasping the other person’s perspective (8).
Perceiving faces, distinguishing between the mother’s face and unfamiliar ones, and recognizing facial emotions and expressions are vital for the development of the perceptual components of ToM. From the very beginning of life, the natural and cultural development of the child merge into each other in such a way (9) that perception becomes social perception—the basic neuropsychological function—and opens the door to ToM development. In fact, recent studies demonstrate that the neural mechanisms supporting basic sensory processing of social information and the theory-of-mind system have an interactive bidirectional relationship (10). Looking, smiling, and smiling back—the first examples of inborn social behavior that appear—are perhaps evidence of an empathic sense of reciprocity between mother and child (11). The child integrates all the information coming from different senses: facial expressions, prosodic differences in the voice of its mother as well as her touch and smell, so as to correspond to the accompanying feeling the mother is expressing. One of the critical stages of ToM development is distinguishing direct from averted gaze, which is the basis for referential gaze perception and communication. Although children can distinguish direct and averted gaze motion at a younger age (12,13), they cannot make explicit judgments of direct gaze and certain inferences until the age of 3 or 4 (14).
Joint attention, which occurs in all sensory modalities, is a shared attention to goal-directed and intentional action. It is present as young as 3 mo (15) but becomes a refined mechanism between the ages of 9 and 18 mo. The recognition of the intentional action of agents—separation of means and ends—is essential for the development of joint action. At 18 mo, children show clear signs of sensitivity to others’ intentions (3). On the other hand, gestures, which sometimes replace verbal language as an effective means of communication between people, play an important role in the development of joint attention. One especially important gesture is pointing, which normally develops between the ages of 9 and 14 mo, after which other conventionally significant gestures appear. Whether the child points to direct the caregiver’s attention to something that might be out of reach or the child looks in the direction of the caregiver’s pointing finger as a way to initiate joint attention, pointing is one of the major milestones in ToM development (16).
The ToM system probably starts to operate in the human from about 13–15 mo of age (4,17,18) at the time when language learning takes place rapidly. At 18–24 mo, convergence of several important developmental milestones, such as true understanding of joint attention, deliberate imitation, and the ability to track a speaker’s intention during learning and decoding of words, occurs.
Pretend (make believe) play, which includes “joint proposals,” “role assignment,” and “metacommunication about a scenario” significantly facilitate ToM development (19). Substituting imaginary situations for real ones, the child begins pretend play around the age of 18 mo, initially prompted by adults, who encourage children to take part in pretend scenarios. Pretend play declines after 6 y. It is one of the areas of development that is most intensely affected in autism (20).