Four experiments examined children's ability to reason about the causal significance of the order in which 2 events occurred (the pressing of buttons on a mechanically operated box). In Study 1, 4-year-olds were unable to make the relevant inferences, whereas 5-year-olds were successful on one version of the task. In Study 2, 3-year-olds were successful on a simplified version of the task in which they were able to observe the events although not their consequences. Study 3 found that older children had difficulties with the original task even when provided with cues to attend to order information. However, 5-year-olds performed successfully in Study 4, in which the causally relevant event was made more salient.Much of the recent research on the development of causal reasoning has emphasized young children's competence with various aspects of causal reasoning (e.g., Corrigan & Denton, 1996;Gopnik, Sobel, Schulz, & Glymour, 2001;Schlottmann, Allen, Linderoth, & Hesketh, 2002). It has been well established that even in infancy children show some type of sensitivity to the causal relationships between events (Leslie, 1982;Oakes, 1994;Oakes & Cohen, 1990) and that children in the preschool years show an appreciation of the causal powers of familiar objects (Bullock, Gelman, & Baillargeon, 1982;Gelman, Bullock, & Meck, 1980) and seem to infer the causal powers of novel objects in principled ways (Shultz, 1982;Shultz & Kestenbaum, 1985). Indeed, the idea that relatively sophisticated causal reasoning abilities are intact early in development has played an important role in the influential "theory-theory" approach to conceptual development.This emphasis on the competence of preschoolers' causal reasoning can be contrasted with a claim by Povinelli, Landry, Theall, Clark, and Castille (1999) that 3-year-olds have difficulty with a fundamental causal ability, a causal ability that Povinelli et al. have linked closely with the development of a concept of time. Specifically, they have argued that children of this age may not grasp that events that occurred in the more recent past may be more relevant to determining the current state of the world than events that took place at an earlier point in time. To use a common example, imagine that you have lost your car keys and are trying to find them. You may mentally retrace the day's events in an attempt to remember what you were doing when you last had the car keys, because you know that this most recent event is the most causally relevant to the current location of the keys. Povinelli et al.'s claim is that 3-year-olds do not have this kind of understanding of the causal relevance of the relative recency of events.They examined this ability in 3-and 5-year-olds (Povinelli et al., 1999, Study 5) using a delayed video feedback technique. Along with an experimenter, children took part in two different games, one after another, in a room in which there were two different colored boxes attached to the wall behind the location where the child was seated. During Game 1, and unbeknow...