As comprehension failure results whenever readers are unable to infer missing causal connections, recent comprehension research has focused both on assessing the inferential complexity of texts and on investigating students' developing ability to infer causal relationships. Studies have demonstrated that texts rely on four types of causal connections; one event may cause: a new physical or mental state, a new action, or a new motivation for action. The density of these stated or inferred connections largely determines text difficulty. Children's spontaneous oral stories can also be analyzed as causal event chains. Analysis reveals that these narratives increase in complexity as children grow, changing from the 2-year-old child's simple listing of events to the 10-year-old child's careful organization of motivations and consequences. The inferential complexity of texts is also reflected in the pauses during the oral retelling of films. Analysis demonstrates that pauses at event chain continuities are less frequent than pauses at discontinuities. (MM)