We examine the interaction of two cues that children use to make judgments about cause-effect relations: probabilities and interventions. Children were shown a "detector" that lit up and played music when a block was placed on its surface. We varied the probabilistic effectiveness of the block, as well as whether the experimenter or the child was performing the interventions. In Experiment 1, we found that children can use probabilistic evidence to make inferences about causal strength. However, when the results of their own interventions are in conflict with the overall frequencies, preschoolers favor the results of their own interventions. In Experiment 2, children used probabilistic evidence to infer a hidden causal mechanism. Though they again gave preference to their own interventions, they did not do so when their interventions were explicitly confounded by an alternative cause.

Research has shown that after observing a sequence of object-related actions, young children sometimes imitate the goal-directed aspects of the actions only, but other times faithfully imitate all aspects of the actions. In this study we explore whether this mixture of goal-directed and faithful imitation is based in part on individual differences between children. Forty-eight 2-year-old children (mean age = 26 months) completed a series of imitation tasks. Results revealed stable individual differences in children’s imitation—measurements of their imitative behavior correlated both within and between different types of imitation tasks. We further used Principle Component Analyses to cluster these correlated measurements into two factors, and the two factors aligned well with the concepts of goal-directed and faithful imitation.