We describe COGNITIO, a computational theory of learning and cognition, and provide evidence of its psychological validity by comparing the protocols of a student learning to program in Smalltalk against a COGNTTIO-based computer simulation of the same. COGNITIO is a production system cognitive architecture that accounts parsimoniously for human learning based on three learning mechanisms: schema formation, episodic memory, and knowledge compilation. The results of simulation support the validity of COGNITIO as a computational theory of learning and cognition. W e also draw some implications of COGNITIO for the teaching of complex problem solving skills.

Sense-making is an essential process in learning for understanding. W e describe a study of sense-making involving two pairs of students learning basic elements of the visual programming language Prograph. The study emphasizes the critical role of activity in mediating concept development and refinement Video protocols of learning behavior were recorded and analyzed. The analysis focuses on the situated nature of the meaning construction process. It reveals how exploration, explanation, and expectation play important roles in the sense-making process.