This study examined how children’s categorization is influenced by adults’ social cues, particularly whether adults performed causal actions before or after a sorting demonstration. In Experiment 1, preschoolers saw the experimenter sort toys with different surface features (colors) and causal properties (sound produced when shaken) into two boxes. When the experimenter shook the toy to produce a sound before sorting (shake-first condition), children were more likely to later categorize the toys based on sound. However, when the experimenter performed the same shaking action after sorting (shake-last condition), children were more likely to sort the toys by color. Experiment 2 further demonstrated that children in the shake-first condition continued to categorize a new set of toys by sound, and they did so even in free play. These results suggest that children use adult’s cues—in particular, the timing of adults’ causal actions—to determine whether causal properties are relevant for categorization.