Young children's attributions of causal power to novel invisible entities.

In two studies, we investigated the development of children's reasoning about potent invisible entities. In Study 1, children aged 2.2-5.5years (N=48) were briefly told about a novel invisible substance that could produce a novel outcome-make a novel box turn green. During this introduction, children watched as one container was inverted over a box and the box lit up green, and then another identical container was inverted over the box and the box did not light up. On test trials, the experimenter inserted a spoon in novel (actually empty) containers and inverted the spoon over the box, which turned green in one trial and did not light up in the other trial. For both trials, children were asked whether there was anything in each container. Children across this age range appropriately reported that an invisible substance was present only when the box lit up. In Study 2, children aged 2.4-4.5years (N=48) watched similar demonstrations but were not explicitly provided information about the invisible substance. Children as young as 3years spontaneously inferred that an invisible substance was present when the box lit up and was absent when the box did not light up. A final task tested children's ability to use their causal knowledge of invisible substances to produce an effect-making the box light up. The youngest children had difficulty with this task, but many children aged 3.5-4.5years performed capably. These results indicate an early-emerging understanding of potent invisible entities that develops rapidly during early childhood.