On the Dynamics of Learner Models

In order for interactive learning environments to enrich and individualize the communication with learners, they use learner models, which can be seen as explicit representations in the system of some characteristics of that particular learner. These explicit learner models are created during the interaction with the learner and based on the actions performed by him or her. The created content of the model will then influence the interaction to be established with that same learner. So, on the one hand, these models are created based on the knowledge interchange between the system and the learner; and, on the other hand, the knowledge interchange between the two may dependon the content of that model. This makes learner modeling a very dynamic process. This dynamic feature of learner models is explored in this document by analyzing the mechanisms of change in learner models and its relation with the behavior of the learner. We define two types of changes: system and learner changes. Finally we describe some characteristics of a system that can cope with the described changes. This system uses a module that keeps the justifications of all the facts in the learner model, used to perform the defined changes.