ABSTRACT
ACT involves a propositional representation for knowledge. This has become a particularly popular idea in the last five years. This chapter will review four recent theories that propose propositional representations-those of Clark (1974), Anderson and Bower (1973), Kintsch (1974), and Norman, Rumelhart, and the LNR Research Group (1975). The ACT theory involves a representation similar to the HAM model of Anderson and Bower. Therefore the section of this chapter dealing with HAM will serve to introduce some representational ideas that will be used throughout the book. The principal goal of this chapter, however, is to identify the common features of the propositional approach. its motivation, and the principal dimensions of variation within the approach. This should provide a background for evaluating ACT's theory of representation.
