The sandbox task-measuring implicit and explicit Theory of Mind

Until recently, Theory of Mind (ToM) – the ability to ascribe mental states to others – was assumed to develop around the age of 4 years. In the past, this capacity was tested using verbal false belief tasks. The last 1.5 decades provided data suggesting ToM abilities already before 2 years of age using non-verbal false belief tasks. Recent data indicates that verbal and non-verbal ToM abilities may rely on different processing systems, often referred to as implicit and explicit ToM. The system underlying implicit ToM, however, requires further investigation and a direct comparison to explicit ToM is missing. We adapted an existing false belief task – the Sandbox task (Bernstein, 2011) – which yields a continuous measure for explicit ToM by measuring an egocentric bias in one’s judgement of another person’s false belief about an object location. In addition, we developed an implicit version of this task, which measures an altercentric bias in one’s own judgement of an object’s location. To establish the task, we tested it in an online study with 96 adults, using Bayesian sequential hypothesis testing we found evidence for an altercentric bias that depended on the order in which the implicit/explicit tasks were conducted. The altercentric bias was only present when participants conducted the explicit task first (BF = 7.33), indicating that the bias may depend on highlighting the agent’s perspective. Currently, we are testing the Sandbox task tablet-based with children aged 3 to 6 years, data collection is ongoing, we anticipate to present the results of 60 children