Differentiation and integration played large roles within classic developmental theories but have been relegated to obscurity within contemporary theories. However, they may have a useful role to play in modern theories as well, if conceptualized as guiding principles for analyzing change rather than as real-time mechanisms. In the present study,…

Four experiments assessed infants' ability to solve isomorphic problems and explored the nature of early representations. Found that 13-month-olds transferred a modeled strategy across isomorphic problems, whereas 10-month-olds transferred only after multiple source problems or high perceptual similarity between problems. Comprehension of the…

Analyzed 1.5- and 2.5-year-olds' problem solving and learning. Found that changes in toddlers' strategies could be assessed reliably on a trial-by-trial basis, that changes followed the basic form predicted by the overlapping waves model, and that analyses could reveal information about the qualitative and quantitative aspects of their learning.…