Proceedings of the Annual Meeting of the Cognitive Science Society

Prior studies of Theory of Mind have primarily asked observers to predict others' actions given their beliefs and desires, or to infer agents' beliefs and desires given observed actions. However, if Theory of Mind is genuinely a causal theory, people should also be able to plan interventions on others' mental states to change their behavior. The intuitive causal model of Theory of Mind predicts an asymmetry: one has to instill both the relevant belief and desire to cause an agent to act; however, to prevent a likely action, it suffices to remove either the relevant belief or desire. Here, we use these asymmetric causal interventions to probe the structure of Theory of Mind. In Experiments 1 and 2, both adults (N=80) and older children (N=42, 8-10 years) distinguished generative and preventative cases: selecting interventions on both mental states (both belief and desire) to induce an agent to act and just one of the mental states (either belief or desire) to prevent an action. However, younger children (N =42, 5-7 years) did not. To probe this age difference, in Experiment 3, we asked younger children(N=42, 5-7 years) just to predict the outcome of others' mental state interventions. Children predicted that interventions were more likely to prevent actions than to cause them, but failed to predict that intervening on both the relevant beliefs and desires is more likely to generate a novel action than intervening on either alone. These findings suggest that by eight to ten years old, people represent the causal structure of Theory of Mind and can selectively intervene on beliefs and desires to induce and prevent others' actions.