Project Summary This research project will develop new strategies for facilitating efficient scientific reasoning about biological concepts during childhood, by identifying what accounts for developmental changes in biological reasoning that my and my sponsor's previous research has discovered. Limitations in young children's biological reasoning can lead them to fundamentally misunderstand scientific concepts and, if not corrected, can result in long-term problems in people's abilities to learn and understand scientific information and to reason about the natural world, health, and medicine. To address these issues, we need to know (a) the nature of developmental changes in biological reasoning, (b) the cognitive and developmental mechanisms that underlie these changes, and (c) how to capitalize on this knowledge to devise new strategies for facilitating efficient conceptual change in the biological domain. Young children (ages 5-6) often appear to think of biological categories in terms of single idealized examples, and to neglect the statistical distribution of properties within and across categories, which can interfere with the acquisition of scientific knowledge and the development of scientific reasoning. Aim 1 will document developmental changes in how children represent biological categories across childhood. Aim 2 will examine the mechanisms underlying developmental changes in these representations. Aim 3 will capitalize on the knowledge produced in Aims 1 and 2 to develop a new strategy for facilitating change in scientific reasoning by targeting representations of biological variation. By partnering with a major informal educational institution (The American Museum of Natural History), we maximize the opportunities for this work to lead to rapid changes in educational practices that will benefit children. .