Making Modularity Work: Combining Memory Systems and Intelligent Processes in a Dialog Agent

Abstract One of the greatest obstacles to designing a mind is the complexity of integrating different process types, time framesand representational structures. This paper describes a methodology for addressing this obstacle, Behavior OrientedDesigned (BOD), and explains it in the context of creating an agent capable of natural language dialogue. 1 Introduction Modularity of some degree and description is almost uni-versally accepted in modern understandings of the oper-ation of human minds. On a physical level, we knowa great deal about the different structures and functionsof various elements of the central nervous system. Thespinal cord, the neocortex, the hippocampus, the amyg-dala, the cerebellum, the lateral geniculate nucleus, thevarious sense organs — while our understanding of thesesystems is not complete, we have begun to know theirindividual architectures and their contributions to intelli-gence as a whole. Similarly, we are developing a set offairly well described psychological modules we know tobe at least partly independent — declarative knowledge,motor skills, episodic memory, drives, emotions, percep-tion, recognition.Controversiessurroundingmodularityfocusnotso muchon its existence as on its nature and extent. The questionof modularity is not whether it exists, but how it is orga-nized. For example, are modules necessarily fully encap-sulated (that is, disconnected from each other) as in Fodor(1983) and Brooks (1991), or can they draw informationfrom each other, as indicated by Karmiloff-Smith (1992)or Ramachandran and Blakeslee (1998). In AI, there is afurther question — how can we as creators of intelligencecreate this order? This paper describes a methodology for addressingthis problem, Behavior Oriented Designed (BOD), andexplains it in the context of creating an agent capable ofnatural language dialogue. The goal is to be able to createa system capable of perception and action; of maintain-ing both local behavioral coherence and global dedicationto multiple, possibly conﬂicting goals; of learning; and,in this case, of expressing itself. This requires the com-bination of parallelism with ordered sequential behavior,and modularitywith coherence. It requires the integrationof both memoryand intentionalityacross several differenttime frames.This paper begins with a full description of BOD. Wethen illustrate the methodology by describing the con-struction of a dialog agent. We have been pursuing re-search in this area for two very different, but not nec-essarily exclusive purposes. The ﬁrst is to leverage thecurrent state-of-the-art in the design of complex agents tothe problem of creating tutorial dialogs. The second isto incorporate semantic and syntactic information gath-ered through statistical natural language processing intoan intentional dialogue agent. Both of these projects arework in progress, but both effectively illustrate importantaspects the problem of designing a mind. The paper con-cludes with a brief discussion of what additional featuresmight be required in BOD for constructing a true “mind,”and whether BOD is compatible with these extensions.