How young children pour equal quantities: A case of pseudocompensation

Two experiments are reported on how 3- to 4.5-year-old children pour equal liquid quantities. An apparent precocity and a decline with age in the ability to judge correctly when different-sized glasses contain the same amount of liquid is demonstrated in Experiment 1. Children of different ages use different strategies to make judgments of equality and this is revealed in Experiment 2. The most primitive strategy fortuitously led the youngest children to make a correct response in Experiment 1 but led to incorrect responses in Experiment 2. Possible explanations of these results are discussed.