The Physics of Animate and Inanimate Entities

Whenever children learn new information, they are faced with the question of how to generalize it appropriately. For example, a child who learns that a particular cat is a "kitty" might assume that "kitty" applies to that cat only (known as underextension), or that "kitty" can apply to animals such as dogs and rabbits (known as overextension).

A number of researchers have sought to determine how children generalize information that they learn about science. Much of this research has focused on children's understanding of biology. One interesting finding is that young children tend to generalize information they learn about people to a much greater extent than they generalize information they learn about animals. For example, if children learn that a person has a spleen, they are likely to assume that a dog has a spleen. However, if they learn that a dog has a spleen, they are far less likely to assume that a person has a spleen.

Our research is looking at these types of questions within the domain of physics. One of our studies of this topic which has been published in a recent paper in Cognition (Heyman, Phillips, & Gelman, 2003) investigated how 5- and 7-year-old children generalized in their projections of physics principles. For example, we taught children that a particular entity such as a girl or a rock weighs less on the moon than on the earth and examined how they generalized the principle to other entities. We found that 5-year-olds, but not 7-year-olds, projected concepts learned about people to inanimate objects to a greater extent than they projected principles learned about inanimate objects to people. These results suggest that children are more likely to generalize information that they learn about people than they are to generalize information that they learn about inanimate entities

Our results also suggested that overall, young children are quite good at recognizing that basic physics principles apply across different types of entities, but that they do not overextend principles in inappropriate ways (e.g., they know that the principles do not a apply to shadows).