In a classic false-belief task, Sally puts a marble in a basket then leaves; Anne moves the marble to a box. A child who has developed theory of mind will predict that when Sally returns, she will look for the marble:
AIn the basket, because Sally doesn't know it was moved
BIn the box, because that is where the marble really is
CIn both places, because she is uncertain
DWherever the child most recently saw it
A child who has developed theory of mind understands that Sally holds a *false belief* — she believes the marble is still in the basket, because she didn't witness the move. Children before about age 3–4 typically answer 'the box,' projecting their own knowledge onto Sally. Children who pass the task answer 'the basket,' correctly modeling Sally's mental state as separate from reality.
Question 2 True / False
A child who fails the false-belief task believes that other people share the same knowledge the child currently has.
TTrue
FFalse
Answer: True
Before theory of mind develops, children tend toward 'reality bias' — they assume others know what they themselves know. Because the child knows the marble is in the box, they predict Sally will also know. This is not a reasoning error about logic; it is a failure to represent other minds as separate epistemic systems that may have different information.
Question 3 Short Answer
Why does theory of mind matter for language and communication beyond predicting where someone will look for an object?
Think about your answer, then reveal below.
Model answer: Effective communication requires modeling what listeners know, believe, and intend. Theory of mind enables children to adapt messages to what others know, understand indirect speech and irony, recognize deception, and engage in collaborative pretend play — all of which require representing mental states that differ from one's own.
Irony works only if you can represent that the speaker means the opposite of what they literally said. Deception works only if you can model that your false statement will create a false belief in the listener. Explaining something to a naive listener requires recognizing that they lack your knowledge. All of these demand the ability to represent divergent mental states — which is exactly what theory of mind provides.