Formal Grammar and Human Factors Design of an Interactive Graphics System

Abstract

Formal grammatical description has not generally been applied in the human factors area, which traditionally draws onbehavioral science for its methodology. This paper illustrates, by means of a detailed example, how formal grammatical description can be used as a predictive tool to compare alternative designs for ease of use and to identify design choices which could cause users to make mistakes. The paper describes the human interface for two versions of an interactive graphics system intended for use by nonprogrammers. It presents the “action languages” for the two versions, then shows how these user languages can be described in terms of a production rule notation. Particular emphasis is given, in the notation, to actions the user has to learn and remember (i.e., to “cognitive” factors). The paper then presents predictions about human performance based on the fonnal description, and exploratory results of testing some of the predictions. Since the predictions are based on general properties of the formal description, the technique should also be applicable to other action languages. Copyright © 1981 by The Institute of Electrical and Electronics Engineers, Inc.