Comparing Function and Affordance as Bases for Design

Abstract

A major objective of engineering design research has been the establishment of design science. Toward this end, there is a need to establish the fundamental concepts that should underlie the basic theories comprising a science of design. The purpose of this paper is to compare two concepts that have been proposed as bases for design—the concept of function and the concept of affordance. After exploring the history-to-date and current application of these concepts of design, they are then compared. In many respects, affordance and function complement each other, such as in describing artifacts and combining existing design methods. However, in other respects, these two concepts differ greatly, as in their theoretical underpinnings, degree of complexity, and acceptance. The issue of the degree of complexity entailed in the two concepts of affordance and function is given particular attention as it of special importance in understanding the differences between affordance and function. It is concluded that the concept of function, because it describes a simple input / output relationship, is appropriate to use in the context of the transformative type aspects of the design of artifacts. However, when the larger complex context of design is considered, including not only the artifact, but the designer and user, and all the interactions in between, the concept of affordance is appropriate because it describe complex relationships. Hence function is an appropriate basis for the design of the transformative technical character of an artifact. However affordance is an appropriate basis for the design activity in general.