Recent research suggests that one of the mechanisms that contribute to infants' acquisition of their physical knowledge is the formation of event categories, such as occlusion and containment. Some of this research compared infants' identification of similar variables in different event categories. Marked developmental lags were found, suggesting that infants acquire event-specific rather than event-general expectations. Other research - on variable priming, perseveration, and object individuation - presented infants with successive events from the same or from different event categories. To understand the world as it unfolds, infants must not only represent each separate event, but also link successive events; this research begins to explore how infants respond to multiple events over time.