Young children can engage in diagnostic reasoning. However, almost all research demonstrating such capacities has investigated children's inferences when the individual efficacy of each candidate cause is known. Here we show that there is development between ages five and seven in children's ability to reason about the number of candidate causes…

This study examines the development of children's ability to reason about proportions that involve either discrete entities or continuous amounts. Six-, 8- and 10-year olds were presented with a proportional reasoning task in the context of a game involving probability. Although all age groups failed when proportions involved discrete quantities,…