Rethinking what is "developmentally appropriate" from a learning progression perspective: The power and the challenge

Learning progressions have recently become increasingly visible in studies of learning and instruction in science. In this essay, I explore the power and considerable challenges in rethinking what may be developmentally appropriate for young children's learning science from the perspective of learning progressions. In particular, I examine the issues of: a) the design of promising learning progressions within the vast design space of potential progressions; b) identification of cognitive resources relevant to a progression; c) analysis of effort / payoff for particular competencies at different points in the progression; d) attribution of cognitive limitations and achievements; e) coordination and collaboration needed to support the design, utilization, and refinement of the learning progression; and f) absence of straightforward correspondence between a learning progression and trajectories of different children's knowledge-development.