The following is a brief summary of Knowledge Acquisition Tools Based on a Personal Construct Psychology

The development of knowledge based systems is the gathering of knowledge, its organization and development into structures suitable for computer implementation in order to emulate high-level skilled performance. In knowledge-based systems the two most emphasized aspects of the development process are 1) human experts as primary sources of information; and 2) knowledge representation schema as the primary basis of implementation.

Personal Construct Psychology was founded by George Kelly, a geometer with experience in navigation and an interest in multi-dimensional geometry, 1905 to 1967. He is credited with the "repertory grid" methodology which is used from eliciting conceptual structures. The methodology bypasses cognitive defenses and gives access to a person's underlying construction system by asking the person to compare and contrast relevant examples. It is based primarily on one aspect of Kelly's personal construct psychology, his dichotomy corollary that, "A person's construction system is composed of a finite number of dichotomous constructs." The repertory grid methodolgy has evolved through its use and now has major differences from that described by Kelly. The emphasis on dichotomous constructs changed to include hierarchical structures of tasks, experts, elements and constructs. These developments in the application of the repertory grid methodology suggest that personal construct psychology can also provide new foundations for existing tools where hierarchical relations are a primary focus.

This section of the paper deals with the fundamental postulate and eleven corollaries of Kelly's Personal Construct Psychology. This has been summarized and discussed in the summary of the paper "Kelly's 'Geometry of Psychological Space' and Its Significance for Cognitive Modeling".

Kelly's topological geometry is easily related to an intensional logic of knowledge representation. Subsumption is the inclusion of one concept within another. The concept that inludes the other concept "subsumes" the other. If concepts don't "overlap" as described above, then they are disjoint.

Subsumption corresponds to increasing generality. It is an asymmetric, transitive relation, a partial pre-order, over distinctions, that supports the ordinal relations of Kelly's organization corollary. Subsumption between computational concepts corresponds to the "is-a" relation in knowledge representation schema.

Disjunction means that a concept disjoint from another, can never be applied whenever the other can.

The function of the repertory grid is to provide a way for the individual to build their conceptual structure without direct elicitation of concepts and theri structures and relationships. ???

Distance measures play an important role in conceptual clustering and induction which is used in analyzing repertory grid data. This section talks about the math used to calculate these distances and how they show relationships between concepts.

It usually takes more than one expert to provide all the required conceptual structures in a domain of interest. The determination of the different combinations of "same terminology" and "different terminology" versus "same distinction" and "different distinctions" is important in determining commonalities and thedegrees of difference in different experts' conceptual structures.