Maintaining Predictions over Time without a Model

A common approach to the control problem in partially observable environments is to perform a direct search in policy space, as defined over some set of features of history. In this paper we consider predictive features, whose values are conditional probabilities of future events, given history. Since predictive features provide direct information about the agent’s future, they have a number of advantages for control. However, unlike more typical features defined directly over past observations, it is not clear how to maintain the values of predictive features over time. A model could be used, since a model can make any prediction about the future, but in many cases learning a model is infeasible. In this paper we demonstrate that in some cases it is possible to learn to maintain the values of a set of predictive features even when a learning a model is infeasible, and that natural predictive features can be useful for policy-search methods.