Carol L. Smith is associate professor of psychology at the University of Massachusetts, Boston. She is interested in understanding how concepts develop and change, in both children and scientists, and why some science concepts are very hard for students to understand. Her research focuses on characterizing students’ initial commonsense theories in some domains (which often contain concepts that are incommensurable with the scientists’ concepts) and understanding the processes by which students can restructure and change these concepts. She has examined the role of several practices in facilitating conceptual change in schooling contexts, and how different schooling contexts affect students’ general conceptions of the nature of science, learning, and knowledge. She recently served as a design team member for the NRC’s Committee on Test Design for K-12 Science Achievement. She has a Ph.D. in personality and developmental studies from Harvard University (1976).