Selected Publications

Opfer, J. E., & Siegler, R. S. (2004). Revisiting the living things concept: A microgenetic study of conceptual change in basic biology. Cognitive Psychology.

Siegler, R. S., & Opfer, J.E. (2003). Development of numerical estimation: Evidence for multiple representations of number. Psychological Science.

Opfer, J. E. (2002). Identifying living and sentient kinds from dynamic information: The role of goal-directed versus aimless autonomous movement in conceptual change. Cognition.

Opfer, J. E., & Gelman, S. A. (2001). Children's and adults' models for predicting teleological action: The development of a biology-based model. Child Development.