Infants' knowledge about occlusion and containment events: A surprising discrepancy

The present research examined whether infants acquire general principles or more specific rules when learning about physical events. Experiments 1 and 2 investigated 4.5-month-old infants' ability to judge how much of a tall object should be hidden when lowered behind an occluder versus inside a con tainer. The results indicated that at this age infants are able to reason a bout height in occlusion but not containment events. Experiment 3 showed th at this latter ability does not emerge until about 7.5 months of age. The m arked discrepancy in infants' reasoning about height in occlusion and conta inment events suggests that infants sort events into distinct categories, a nd acquire separate rules for each category.