One outcome of recent progress in educational technology is strong interest in providing effective support for learning in complex and ill-structured domains. We know how to use technology to promote understanding in simpler domains (e.g., orientation information, procedures with minimal-branching, etc.), but we are less sure how to use technology to support understanding in more complex domains (e.g., managing limited resources, understanding environmental impacts, etc.). Such domains are increasingly significant for society. Technology (e.g., collaborative tele-learning, digital...