Inference and action in early causal reasoning.

Two experiments investigated whether a simple-to-embedded-rules account can explain the change in causal reasoning in children between 3 and 4 years of age. A marble-and-ram p apparatus that operated in 2 distinct configurations of straight and across was used throughout. In Experiment 1, 3-year-olds were able to predict the path of the marble when there was only 1 input hole (a simple ifthen rules task), whereas only 4-year-olds could solve the 2-input version (an embedded or conjoint conditional if-then rules task). Experiment 2 found the same 3- to 4-year age difference when children chose where to insert the marble in the 2-input version, indicating that the same rules may underlie causal action as well as causal prediction for the more complicated task. The results of the 2 experiments are discussed in relation to previous findings on causal reasoning, children's theory of mind, and a theory of cognitive complexity in the preschool period. Inferring causes greatly increases children's understanding of the world. Instead of seeing unconnected events—one object colliding with another and the second one moving off—the child can identify the first as the cause of the second. Simple causal reasoning makes explanation possible; the child can refer to the first object to explain why the second one moved. It also allows prediction. In similar circumstances, the child is able to anticipate the outcome of the first object hitting the second. Finally, it grants a new range of action. To make the second event occur, alternatives besides acting directly on that event become possible. The child can as easily act on the first event, knowing that it will cause the second to occur. It has been proposed that there is a change in causal reasoning during the preschool period because of a change in the complexity of inference rules children can use (Frye, Zelazo, Zelazo, Frye, Reznick, Schuster, & Argitis, 1995). According to this account, younger preschoolers can use simple if-then rules. In contrast, older preschoolers can form if—if— then or embedded rules. Embedded rules act to restrict the operation of the simple rules by making them dependent on setting conditions. These inference rules are assumed to be general, so it is expected that they will apply not only to physical