Conceptual development in infancy: the understanding of containment.

In each of 2 experiments, 2 measures were used to assess infants' understanding of the concept of "containment." After being habituated to videotaped episodes of sand being poured into and out of a cylinder, infants saw a "possible" event and then an "impossible" event. Infants who understand containment were expected to look longer at the "impossible" event. In the second test, infants were involved in a game of dropping blocks into a cup. In Experiment 1, 14-month-olds were contrasted with 20-month-olds to establish that the latter but not the former demonstrate an understanding of containment on both tasks. This age effect was obtained. In Experiment 2, we examined whether this understanding could be acquired by 14-month-olds. 50 infants were randomly assigned to 5 training conditions. 1 condition was effective in leading to the development of an understanding of containment: Infants who played with both cans and tubes in their home for 1 month performed in both tests similarly to untrained 20-month-olds.