This paper describes an approach to user adaptation realized in a multiagent interface system for interaction with a virtual environment. The interface

. This paper describes a multi-agent learning approach to adaptation to users' preferences realized by an interface agency. Using a contract-net-based negotiation technique, agents as contractors as well as managers negotiate with each other to pursue the overall goal of dynamic user adaptation. By learning from indirect user feedback, the adjustment of internal credit vectors and the assignment of contractors that gained maximal credit with respect to the user's current preferences, the preceding session, and current situational circumstances can be realized. In this way, user adaptation is achieved without accumulating explicit user models but by the use of implicit, distributed user models. 1 Introduction Interface agents are computer programs that enhance the human-computer interaction by mediating a relationship between technical systems and users [Lau90]. On the one hand, they provide assistance to users by acting on his/her behalf and automating his/her actions [Nor94...