Capability, Potential and Collaborative Assistance

This paper is concerned with the issue of adjusting the complexity, content and assistance in interactive learning environments (ILEs). In particular, it describes the structure and evaluation of the learner model implemented within VIS (the Vygotskian Instructional System). This software explores the way that Vygotsky's Zone of Proximal Development can be used in the design of learner models. This theoretical foundation requires the system to adopt the role of a more able assistant for a learner. It must provide appropriately challenging activities and the right quantity and quality of assistance. The learner model must track both the learner's capability and her potential in order to maintain the appropriate degree of collaborative assistance. Within VIS the learner model is a Bayesian Belief Model overlay of the domain knowledge structure. An evaluation of the system illustrates that the approach adopted by VIS promotes the construction of productive interactions with the majority of learners, across a range of abilities. The learner model within VIS is in effect an operational definition of the ZPD of each learner who interacts with the system