ABSTRACT
Measuring and comparing student learning in adaptive computer assisted learning (ACAL) systems is problematic because the system is trying to both model and change the user, and in this sense is chasing a moving target. Processoriented metrics for measuring learning, such as the zone of proximal development (ZPD) can be more robust in such situations. Though the concept of the ZPD is often invoked in the context of instructional systems, it has not been operationalized in a manner that allows it to be used in ACAL. We propose a straight-forward method for measuring ZPD-learning that focuses on the ongoing amount of hints or help that learners need as they solve problems. The ZPD is commonly used to articulate apprenticeship learning approaches, scaffolding and fading (note: references removed from this extended abstract, available from the authors), and authentic (situated) learning tasks. The ZPD describes a zone within which tasks are too difficult to accomplish without assistance, but which can be accomplished with some help. The ZPD in terms of a student’s ‘‘readiness” to learn a new skill in terms of the assessment of learning potential or “learnability”. These descriptions of the ZPD are useful for framing certain educational issues, but they are not defined in an operational way. We argue that keeping the learner within this optimal zone could be described in several compatible ways:
Putting a greater emphasis on monitoring learning processes variables and maintaining efficient as well as effective learning;
Cognitively there is a goal to presenting material that is neither too easy nor too difficult;
Affectively there is a goal of avoiding the extremes of boredom and confusion (being overwhelmed);
This can also be seen as maintaining a constant level of challenge (and support), or a constant ‘‘rate” of learning.
