9615922 HUNTLEY-FENNER This research will address two issues. The first is the development of physical knowledge in infancy, specifically when and how infants come to distinguish between objects and noncohesive particulate materials such as sand or flour. The second is the development of quantificational reasoning, such as the distinction between "how much" and "how many." There is considerable evidence that infants have a sophisticated understanding of the physical world. Much of this evidence comes from research focused on infants' understanding of objects. But, as adults, our physical reasoning encompasses an understanding both of objects and of noncohesive and particulate substances. Such substances are similar to objects, since both are material entities subject to the constraints of space and time and, for instance, neither can pass through a physical barrier. However, only objects cohere when moved. The first part of this research will address whether infants monitor the properties of a stimulus, be it an object or not, and the properties of the surface onto which it is lowered to judge whether the stimulus will be supported or not. The second part will build on the fact that objects and noncohesive substances are quantified differently, with objects being inherently individuated and noncohesive substances continuing to be the same kind of stuff whether they are separated into arbitrary pieces or whether scattered portions are coalesced into one. This part will determine whether infants are capable of using both quantificational strategies, such that in some cases judgments are made about discrete quantities and in others made about continuously measured abilities. This research will, thus, contribute to our understanding of the capabilities of very young infants that afford their development into adults who can function easily in our complex society. ***
