Abstract: When inferring the extent of others’ knowledgefrom samples of what they know, certain kinds of samplesimply richer content. One candidate kind is knowledge ofcausal mechanism. In the current study, we investigatewhether children and adults think that knowledge aboutmechanism generalizes more broadly than non-mechanisticfactual knowledge. We find an early-emerging assumptionthat mechanistic knowledge about a basic level categoryimplies greater knowledge about a superordinate category,compared to factual knowledge about the same basic levelcategory. Even young children have a sophisticated sense ofhow causal mechanisms generalize across categories, despitepossessing little mechanistic knowledge themselves. Theseintuitions likely support the epistemic inferences we makefrom early childhood onward.

Previous work has argued that young children do not answercounterfactual questions (e.g. “what would have happened?”)by constructing simulations of alternative possibilities in theway adults do. Here, we propose that children can engage insimulation when answering these questions, but considerdifferent counterfactual possibilities than adults. While mostprevious research has relied on narrative stimuli, we use causalperception events, which are understood even in infancy. InExperiment 1, we replicate earlier findings that childrenstruggle with counterfactual reasoning, but show that they arecapable of conducting the required simulations in a predictiontask. In Experiment 2, we use a novel multiple-choice methodthat allows us to study not only when children get it right, butalso how they get it wrong. We find evidence that 4-year-oldsengage in simulation, but preserve only some features of whatactually happened and not others.