Why? You must be able to hold two contradictory ideas at once. First, you must know the true state of the world: the marble is in Anne's basket. Second, you must understand Sally's flawed perspective of the world: Sally believes the marble is still in her own basket. In other words, you must simultaneously maintain both a true belief and a false belief in your mind without confusing the two. This talent is a signature of “theory of mind” – an ability I have been exploring in my previous two columns, on deception and distinguishing intention from happenstance. We share those two simpler forms of mindreading with other animals – but passing the Sally-Anne test requires far more sophisticated thinking. Callaghan, T., Rochat, P., Lillard, A., Claux, M. L., Odden, H., Itakura, S., …& Singh, S. (2005). Synchrony in the onset of mental-state reasoning: Evidence from five cultures . Psychological Science, 16 (5), 378-384.

An example of the control condition, referred to as the false photograph story, is “A photograph was taken of an apple hanging on a tree branch. The film took half an hour to develop. Theory of mind (ToM) is the ability to attribute mental states to ourselves and others, serving as foundational elements for social interaction. Understanding that “seeing leads to knowing”: The third stage is recognizing that others have different knowledge access, and if someone hasn’t seen something, they will need extra information to understand. Theory of mind is an important underlying mechanism that allows human social interaction. Without it, we would greatly struggle to communicate with each other, understand each other’s behavior, and we wouldn’t be known as the unique social beings that make us so special.Most theory of mind studies are conducted with toddlers and infants. Because this is a developmental concept, researchers are concerned with the age at which individuals adopt a theory of mind. Experimenters ask children to predict another child’s perception of the contents of a box that looks as though it holds a candy called “Smarties” (that actually includes a pencil) (Gopnik & Astington, 1988). Simon Baron-Cohen (1985) used the Sally–Anne task to investigate whether autistic children could understand false-belief. These skills include the ability to comprehend the concept of attention, understand the intentions of others, and the ability to imitate others are all rungs on the ladder you must climb before reaching the platform of theory of mind.

Luchkina, E., Sommerville, J. A., & Sobel, D. M. (2018). More than just making it go: Toddlers effectively integrate causal efficacy and intentionality in selecting an appropriate causal intervention . Cognitive Development, 45, 48-56. O Connell, S., & Dunbar, R. I. M. (2003). A test for comprehension of false belief in chimpanzees. Evolution and Cognition, 9(2), 131-140.Aunt Sally is played in the British detective television series Midsomer Murders in episode 5 of series 4, "Dark Autumn", and episode 1 of series 22, “The Wolf Hunter of Little Worthy” Together, these examples illustrate that while humans do have a unique ability to detect mental states in others, for some, this ability is reduced or not present at all, thus making social interaction challenging and all the more stressful. ToM in The Brain Ruffman, T., Slade, L., & Crowe, E. (2002). The relation between children’s and mothers’ mental state language and theory‐of‐mind understanding. Child development, 73 (3), 734-751. Does this mean that this sophisticated form of theory of mind is uniquely human? Probably not. The eyegaze of the apes suggested they knew Sally was looking in the wrong place.