9514575 MANDLER This research will examine the development of conceptual thought in infancy and early childhood. Until recently there has been little experimental work on this topic, but it has been assumed that infants first form concepts about concrete objects, such as dogs, chairs, and cars, and only later develop broader concepts of animals, furniture, and vehicles. However, prior research from Mandler's laboratory indicates that the broader concepts actually precede the more specific ones. For example, 6-month-olds can see the difference between dogs and cats but conceptually they treat them both as the same kind of thing. This research will extend these findings to show how infants from 9 to 15 months form their first inductive generalizations about the characteristics of animals, vehicles, and other classes, for example, how they determine what kind of objects eat and what kind of objects get ridden. Several recently-devised techniques will be used to study these issues. One technique is to measure how infants categorize little models of real-world objects. Another technique is to see whether infants are more willing to imitate appropriate behavior on these objects (such as giving a dog a drink) than inappropriate behavior (giving a car a drink). The research will also study early comprehension of object labels, to see how broadly or narrowly infants interpret their meaning. The overall goal of the research is to provide a systematic body of knowledge about the preverbal foundations of concept formation and thought and its relation to early language acquisition and preschool learning. ***