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Theory of Mind: The False-Belief Task

A cognitive science experiment that explores how children understand others' mental states.

mysimulator teamUpdated June 2026≈ 3 min read▶ Open the simulation

What Is Theory of Mind?

Theory of mind refers to the ability to attribute mental states—beliefs, intents, desires, emotions—to oneself and others. It is crucial for social interaction as it allows us to understand that other people may have different beliefs or knowledge from our own.

The false-belief task, particularly the Sally-Anne scenario, is a widely used method in developmental psychology to assess this ability in children.

The False-Belief Task: The Sally-Anne Scenario

In the classic Sally-Anne experiment, two characters, Sally and Anne, are introduced. Sally hides a marble in her basket while Anne is away, then returns. Anne hides the marble in her box when Sally leaves to get a toy. When asked where Sally will look for the marble upon her return, children under 4 years old typically say that Sally will look in the box because they believe Anne moved it there. This shows a lack of understanding that others may have different beliefs.

Children who pass this task are considered to have developed a theory of mind and can understand that others might hold false beliefs based on their experiences.

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Second-Order Theory of Mind

A second-order theory-of-mind question extends the concept by introducing an additional layer of complexity. For example, if Anne is distracted while hiding the marble in her box and Sally sees this, children must understand that Sally now has a false belief about where Anne thinks the marble is.

Passing such tasks indicates that children can grasp not only others' beliefs but also their knowledge about what others believe.

Developmental Stages and Theory of Mind

Research shows that theory-of-mind abilities develop gradually in early childhood. Most children start to pass the Sally-Anne task around 4-5 years old, although individual differences exist.

Understanding how these cognitive milestones unfold helps educators and psychologists design interventions to support social development.

Frequently asked questions

What is a false-belief task?

A false-belief task, such as the Sally-Anne scenario, tests whether someone can understand that others may have beliefs different from their own or from reality.

Why is theory of mind important?

Theory of mind is crucial for social interactions and understanding others' perspectives, which are fundamental aspects of human communication and cooperation.

At what age do children typically pass the Sally-Anne task?

Most children start to pass the Sally-Anne task around 4-5 years old, but this can vary depending on individual development and cognitive abilities.

How does a second-order theory-of-mind question differ from the original Sally-Anne scenario?

A second-order theory-of-mind question involves understanding that someone knows something about another person's beliefs. For example, if Anne is distracted while hiding the marble in her box and Sally sees this, children must understand that Sally now has a false belief about where Anne thinks the marble is.

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