Can children of all age groups engage in self-directed learning? While active learning has been widely advocated in education, it remains unclear whether its benefits apply to children at all developmental levels. In the present study, we demonstrate that 19-month-old toddlers acquire higher-order generalizations in the causal domain only when their play is facilitated by an adult experimenter or a parent, and not when they are provided with full instruction or complete free play. These findings stand in contrast with earlier findings that 36-month-old children can learn effectively from data they generate by themselves under conditions of complete free play. This difference suggests that the ability to engage in self-directed learning may develop over early childhood.