CURRENT DIRECTIONS IN PSYCHOLOGICAL SCIENCE Evaluating the Theory-of-Mind Hypothesis of Autism Helen Tager-Flusberg Boston University School of Medicine ABSTRACT—Two decades ago, the theory-of-mind hypoth- Two decades ago, Baron-Cohen and his colleagues revolu- esis of autism was introduced by Baron-Cohen and his tionized autism research when they introduced the theory- colleagues; this theory provided a unified cognitive expla- of-mind hypothesis to explain the main behavioral symptoms nation for the key social and communication symptoms in that characterize this neurodevelopmental disorder. Their initial that disorder. I evaluate the theory-of-mind hypothesis in studies showed that most children with autism whose mental and light of studies that have addressed several key questions: verbal abilities were well beyond the 4-year-old level never- Do children with autism develop theory-of-mind concepts? theless failed the Sally–Anne task and other related tasks How can we explain why some children with autism pass (Baron-Cohen, Leslie, & Frith, 1985). Deficits in the acquisition theory-of-mind tasks? Do deficits in theory of mind account of a theory of mind provided a plausible explanation for the major for the major impairments that characterize autistic dis- symptoms of autism, especially impairments in social reci- order? Current research supports the view that autism procity and communication, thus providing the first integrated involves delays and deficits not only in the development of account of the cognitive mechanisms that might underlie several a theory of mind but also in additional aspects of social- key behaviors that define the disorder. The original studies have affective information processing that extend beyond the been replicated many times by different research teams, and traditional boundaries of theory of mind. there is little doubt that children with autism have difficulty attributing mental states to themselves or to other people. KEYWORDS—autism; theory of mind; social cognition; com- Yet despite the robustness of the empirical findings, there is munication now less excitement and increasing skepticism among many investigators about the significance of the theory-of-mind hy- Daily social life depends on the ability to evaluate the behavior pothesis of autism. Questions about the universality and of other people on the basis of their mental states, such as their uniqueness of theory-of-mind impairments in autism, and about goals, emotions, and beliefs. This is accomplished by dedicated how this hypothesis could account for the earliest manifestations cognitive systems, collectively referred to as theory of mind.By of autistic symptoms, have been raised (Tager-Flusberg, 2001). age four, children normally pass tasks that tap mental-state Autism is generally defined on the basis of impairments not only understanding, including the hallmark false-belief tasks that in social and communicative functioning but also in restricted require a child to distinguish between the world as it really is and or repetitive behavior patterns. The theory-of-mind hypothesis the way it might be represented (incorrectly) in the mind of does not extend to explaining these areas of impairment; nor another person. In the classic Sally–Anne false-belief task, a does it explain some of the strengths that are characteristic of child is told the following story, accompanied by supporting people with autism, such as their superior visual-attention skills. pictures or toy props: Sally places her ball in a basket and goes The past decade has witnessed an exponential increase in out to play; while she is gone, Anne takes the ball from the basket research on autism. Today, autism is clearly understood to be a and hides it inside a box. The child is then asked where Sally will complex and heterogeneous set of related developmental dis- look for the hidden ball (or where she thinks it will be located) orders in which no single cognitive mechanism or cause can when she returns to play with it again (see Fig. 1). account for the variety of symptoms and range in their expres- sion. Even the social-communication impairments cannot be explained exclusively on the basis of theory-of-mind impair- ments. Nevertheless, current research supports the view that Address correspondence to Helen Tager-Flusberg, Department of Anatomy & Neurobiology, Boston University School of Medicine, 715 children and adults with autism have problems processing Albany Street L-814, Boston, MA 02118; e-mail: [email protected]. mental-state information; that when they are able to infer mental Volume 16—Number 6 Copyright r 2007 Association for Psychological Science 311 Theory-of-Mind Hypothesis of Autism pass false-belief tasks. At the same time, research has shown that older children with different disorders (e.g., nonsigning deaf children; Peterson, Wellman, & Liu, 2005) fail these tasks— evidence that challenges the notion that theory-of-mind deficits are universal and specific to autism. More recent studies have taken a developmental approach by including a wider range of tasks that tap a child’s ability to reason about mental states from the early preschool years to adoles- cence. For example, Steele, Joseph, and Tager-Flusberg (2003) conducted a longitudinal study in a large sample of children with autism; the participants were administered a battery of nine developmentally sequenced reasoning tasks ranging from tasks appropriate for toddlers (assessing the ability to understand the concept of pretense and the ability to attribute desire to others), young children (assessing the ability to correctly match others’ emotions to situations and to understand others’ knowledge and false beliefs), or older children and young adolescents (assessing understanding of others’ second-order false belief, nonliteral language, traits and intentions, and moral judgments). Over two thirds of the children made some gains over the course of 1 year, and although all the children were delayed relative to their age, a small number of the most able adolescents passed some of the more advanced tasks. Peterson and her colleagues (Peterson et al., 2005) used a set of five tasks that formed a coherent scale of theory-of-mind concepts, from desire to false belief and hid- den emotions. The children with autism were generally similar to the other groups in their ability to pass the tasks according to their developmental sequence, but unlike the other groups, children with autism found false belief harder than hidden Fig. 1. The Sally–Anne false-belief task. To test theory-of-mind skills, emotions. While children with autism develop some under- children are presented with a story in which (from the top frame to the bottom) Sally (left) has a basket and Ann (right) has a box; Sally puts her standing of desire and emotion, belief and other cognitive states marble in the basket; Sally leaves; Ann takes the marble from the basket seem to pose a unique challenge to this population. and puts it in the box; and Sally returns to look for the marble. Subjects are then asked whether Sally will look for the marble in the basket or the box. Reprinted from Autism: Explaining the Enigma, by U. Frith, 1989, EXECUTIVE FUNCTIONS, LANGUAGE, AND THEORY Blackwell Publishers, p. 83. Copyright 1989, Blackwell Publishers. OF MIND IN AUTISM Reprinted with permission. An important question that has generated considerable research states, they tend not to use the same neurocognitive systems as focuses on how some children with autism pass theory-of-mind do nonautistic people; and that performance on theory-of-mind tasks. For nonautistic children, performance on classic theory- tasks can account for some, though not all, of the severity of the of-mind tasks reflects intuitive social insights into people or social and communication symptoms that define this disorder. conceptual knowledge of mental states coupled with general cognitive skills that support the verbal processing, memory of A DEVELOPMENTAL PERSPECTIVE ON THEORY OF key narrative events, and inhibition of spontaneous responses MIND IN AUTISM that are central to the tasks. In contrast, studies of children with autism suggest that such children treat theory-of-mind tasks as Most studies investigating theory of mind in autism focused on logical-reasoning problems, relying primarily on language and the transition that takes place at the age of four, when children other nonsocial cognitive processes in lieu of social insight. typically first understand false belief. This narrow perspective Children with autism generally have executive-function appeared to reduce a complex social-cognitive developmental deficits that require planning, flexibility, or working memory progression to a categorical capacity indexed by passing or combined with inhibitory control (Ozonoff et al., 2004). Perfor- failing a single task, thus encouraging the notion that autism mance on false-belief tasks by both typically developing chil- could be defined as the ‘‘absence’’ of a theory of mind. Yet in all dren and children with autism is significantly related to these studies that have been conducted, some children with autism aspects of executive control (Joseph & Tager-Flusberg, 2004). 312 Volume 16—Number 6 Helen Tager-Flusberg Children with better planning skills and inhibitory control are theory of mind is not based on the same foundational social in- more likely to pass false-belief tasks, supporting the view that sights that are provided by a domain-specific theory-of-mind successful performance on false-belief tasks requires one to mechanism. This conclusion is consistent with functional neu- maintain a false representation of an event in working memory roimaging studies, which have shown that high-functioning while resisting the tendency to predict a person’s action on the adults with autism who pass theory-of-mind tasks activate basis of what one knows to be true. different brain regions when solving such problems. When Language ability has also been closely linked to the devel- nonautistic controls process theory-of-mind tasks they typically opment of theory-of-mind skills (see Astington & Baird, 2005).