How do children evaluate complex causal events? This study investigates preschoolers' representation of "force dynamics" in causal scenes, asking whether (a) children understand how single and dual forces impact an object's movement and (b) this understanding varies across cause types (Cause, Enable, Prevent). Three-and-a half- to 5.5-year-olds ("n" = 60) played a board game in which they were asked to predict the endpoint of a ball being acted upon by one or two forces. Children mostly understood the interactions of forces underlying each type of cause; only 5.5-year-olds could integrate two contradictory forces. Children perceive force interactions underlying causal events, but some concepts might not be fully understood until later in childhood. This study provides a new way of thinking about causal relations. (Contains 4 figures.)