Kelly's "Geometry of Psychological Space" and its Significance for Cognitive Modeling

Shaw & Gaines The New Psychologist, 23-31, October 1992

Article Summary

Personal Construct Psychology: A theory of individual and group psychological and social processes that has been used extensively in knowledge acquisition research to model the cognitive processes of human experts.

Kelly's Geometry of Psychological Space: Based on an intensional logic, one in which predicates are defined in terms of their properties rather than extensionally in terms of those entities that fall under them. Kelly introduces the notion of psychological space as a term for a region, or space, in which we may place and classify elements of our experience. According to Kelly, humans create dimensions in personal psychological space as a way of providing a coordinate system for our experience; we construct this space out of elements as we come to construe them. The intensional nature of personal construct psychology comes from an emphasis on the space itself being created by a process of making distinctions rather than being defined by the elements distinguished.

Constructs and Concepts: 'Constructs' are operationally defined as being both parallel to and distinct from the common usage of 'concept'. The relationship between the 19th century use of 'percepts', which carry the idea of its being a personal act, and the present use of 'constucts' is identified. However, to further define constructs, the notion of it being an 'abstraction' is introduced, which relates to the traditional use of 'concepts'. Within Kelly's system of logic, the notion of contrast as being distinct from irrelevancy is part of the assumptive structure of the way people think. The dichotomous aspect of constructs, then, is the most significant aspect of the difference between Kelly's use of 'constructs' and the present term 'concept'.

A Visual Language for the Logic: A construct's range of convenience comprises all those things to which the user would find its application useful, focus of convenience those particular things to which the user would find its application maximally useful, and the context is somewhat more restricted than the range and somewhat more extensive than the focus of convenience. Anticipation is introduced within the geometry by Kelly attaching actions to regions of psychological space. Regions are defined as the intersection of multiple axes of reference, and the planes representing their distinctions and ranges of convenience. Kelly's theory of anticipation is based on attaching significance to recognizable intersections of a set of properties. The logic remains intensional because there is no implication that elements have already been construed within the intersections. Kelly explains a construct in terms of how elements were placed in the framework of existing constructs, or the existing constructs are adjusted to account for the new element. Material implications, or rules, correspond to a commitment to place an element that falls in the intersect in the region defined by the pole of some other construct also. Rules allow the cognitive system to be anticipatory by using distinctions made about an event which may lead to a prediction or action.

The Repertory Grid: Kelly (1955) introduces the role repertory grid as a means for investigating a person's conceptual structure relevant to inter-personal relations by having them classify a set of people significant to them in terms of elicited personal constructs. Although repertory grids and techniques for manual elicitation have been used without computer support, repertory grid methodologies are easier to implement using computer-based knowledge elicitation tools, which enable the elicitor to manage feedback from the elicitee as well as minimizing inter-personal interactions that may distort the elicitee's conceptual structures. Additionally, a GUI allows for continual refinement and editing of the elicitee's conceptual structure as it emerges.

Conclusion: Shaw & Gaines' (1992) paper brings several elements together into a framework for understanding existing knowledge acquisition tools and techniques. Personal Construct Psychology is suggested as a strong foundation for knowledge acquisition methodologies and tools that have to bridge the gap between human cognitive processes and computational knowledge representation.

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