Development of the perception of object containment in 9‐ to 16‐month‐olds

In the present study, 9‐, 12‐ and 16‐month‐old infants were familiarized to a block that was repeatedly lowered into a container and lifted from that container again. In the subsequent test phase, the block passed through the container opening either without making contact with the container rim or colliding with the rim in three places but ‘magically’ passing through. In Experiment 1 an opaque black screen was positioned just below the blocks' starting position. In Experiment 2 the screen was put at the height of the container rim and thus occluded the critical arrival phase of the trajectory. Results showed that looking times depended on what infants perceived as happening at the height of the rim and not on what they could have perceived before the block reached the opening, such as the absolute size of the objects. In contrast, older infants looked longer at an obstructed passage of the block into the container, irrespective of the position of the screen.