Theory of Mind

Theory of Mind: The Sally-Anne Study

Theory of mind (ToM) is the ability to attribute mental states — beliefs, desires, intentions, knowledge, emotions — to oneself and to others, understanding that these mental states can differ from reality and from one's own. It is often described as understanding that 'other people have minds' in a meaningful sense — that behaviour is guided by internal mental representations rather than directly by external reality. ToM underlies empathy, deception, communication, and social understanding generally.

The False Belief Task

The key test of ToM is the false belief task — a scenario in which a character holds a belief that is false (because they lack information available to the observer). To pass, the child must predict the character's behaviour based on the character's (false) belief, not based on what the child knows to be true. This distinguishes genuine ToM (representing the character's belief as distinct from reality) from simply tracking reality or one's own knowledge.

Wimmer and Perner (1983) developed the original false belief task — the Maxi task. Maxi hides chocolate in a blue cupboard and then leaves the room. His mother moves the chocolate to a green cupboard. Where will Maxi look for his chocolate when he comes back? Children under approximately 4 years consistently answer 'the green cupboard' — the actual location — rather than 'the blue cupboard' where Maxi believes it to be. Older children correctly predict that Maxi will look in the blue cupboard, demonstrating understanding of his false belief.

The Sally-Anne Study (Baron-Cohen, Leslie and Frith, 1985)

Baron-Cohen, Leslie and Frith (1985) developed a simplified, more accessible version — the Sally-Anne task — to test three populations: typically developing children (average age 4 years), children with Down syndrome (average age 10 years), and children with autism (average age 12 years). In the task, two dolls — Sally and Anne — are introduced. Sally places a marble in her basket and leaves the scene. Anne takes the marble from Sally's basket and places it in her box. Sally returns. The child is asked: 'Where will Sally look for her marble?'

Results: 85% of typically developing children (aged 4+) correctly answered 'in the basket' — demonstrating ToM. 86% of children with Down syndrome also passed — consistent with their general level of cognitive development. Only 20% of children with autism passed — the majority incorrectly answered 'in the box' (the actual location). This finding suggested that autism is associated with a specific impairment in ToM — mindblindness (Baron-Cohen, 1995) — rather than a general intellectual disability.

First-Order and Second-Order ToM

First-order ToM: understanding that someone holds a false belief about the world ('Sally thinks the marble is in the basket'). Typically passes at age 4. Second-order ToM: understanding that someone holds a false belief about another person's belief ('Mary thinks that John thinks the ice cream van is at the park'). Typically passes at age 6–7. Happé (1994) developed strange stories — testing higher-order ToM through understanding of figurative language, irony, and white lies — which require understanding that the speaker's meaning may differ from their literal words.

ToM and Autism

Baron-Cohen's mindblindness hypothesis proposes that autism spectrum disorder is characterised specifically by impaired ToM development — the inability to attribute mental states to others — which explains the social communication difficulties characteristic of ASD. This does not preclude other features of autism (sensory processing, special interests) but identifies a core social-cognitive deficit. Subsequent research has refined this: many autistic individuals do eventually develop ToM but may do so later and through different cognitive routes. Some high-functioning autistic individuals pass first-order tasks but fail second-order or strange stories tasks.