Sally-Anne Test

In 1985, Simon Baron-Cohen, Alan Leslie, and Uta Frith at the MRC Cognitive Development Unit in London adapted Heinz Wimmer and Josef Perner's false-belief puppet paradigm into what became known as the Sally-Anne test. Children watch two dolls, Sally and Anne: Sally hides a marble in her basket and leaves the room, Anne then moves the marble to her own box, and the child is asked where Sally will look for it first. Correctly answering the basket requires representing a belief the child knows to be false, a mental-state inference the researchers took as a marker of theory of mind. Comparing a group of autistic children against mental-age-matched children with Down syndrome and typically developing children, the study found autistic children, despite normal or above-average performance on control questions, failed the belief question far more often than either comparison group. The result, published in the journal Cognition, became a founding demonstration for the theory that autism involves a specific difficulty attributing mental states to others, independent of general intellectual ability.