This paper presents a computational theory of developmental mental architectures for artificial and natural systems, motivated by neuroscience. The work is an attempt to approximately model biological mental architectures using mathematical tools. Six types of architecture are presented, beginning with the observation-driven Markov decision process as Type-1. From Type-1 to Type-6, the architecture progressively becomes more complete toward the necessary functions of autonomous mental development. Properties of each type are presented. Experiments are discussed with emphasis on their architectures. r 2007 Published by Elsevier B.V.

The evolution of tool design for the creation of user interfaces has progressed to incorporate visual techniques for the construction and placement of interface controls. This application of visuality has produced measurable gains in usability. Underlying these tools however, are nonvisual programming languages used for the behavioral definition of the controls. This design results in a higher level of complexity and decreases usability as developers are required to keep two very different mental models of a program in their heads and continuously switch between them. This produces poorly designed tools for both interface designers and for programmers. Our approach is to bridge the gap between the behavioral and structural definition of an interfaces development by using a combination of visual and interaction techniques we call the reactant. We apply the reactant to the design of a tool called ReactoGraph. 1.