Knowing How to Project Objects: Probing the Generality of Children's Action Knowledge

Previous work on the development of intuitive knowledge about trajectories has shown a dissociation between young children's aimed throwing actions, in which they are highly sensitive to the physical laws of motion, and their explicit judgments, in which they exhibit misconceptions. This research investigated the generality of children's action knowledge by having the participants project a ball with a sling. Instead of adjusting sling stretch, and hence sling force, correctly as a function of both the release height and the target distance, 5- and 6-year-olds (Experiment 1, N = 32) and, without flight feedback, even most 7- to 10-year-olds (Experiment 2, N = 96) considered distance only and ignored the height dimension. Similarly, children's judgments of the required sling stretch tended to follow a distance-only rule, especially with children younger than 9 years of age. These results show that young children's action knowledge exhibited in throwing does not generalize to arbitrary means of force production. They further suggest that there is no developmental trend toward such generalization in the age range examined.