This study examined if 12- and 16-month-olds’ causal perception can guide their expectations about objects’ internal energy during stopping events. Thirty-seven infants were habituated to a causal event in which a red ball (agent) launched a green ball (recipient). Infants were tested on trials in which the agent and the recipient maintained their energy before stopping abruptly, or both objects lost energy as they stopped gradually. Preliminary results indicate that infants in both age groups looked significantly longer when agents lost energy than when they maintained it, but looked equally long at both trials for recipients. Results also show a trend of 12-month-olds looking longer than 16-month-olds at the recipient trials. Findings suggest that by 12 months, infants expect agents to maintain their internal energy, and that developmental changes in perceptions of recipients occur between 12 and 16 months. Fourteen-month-olds are currently being tested to clarify this developmental trend.