Central-composite experimental designs for exploring and fitting response surfaces were developed nearly twenty years ago. In spite of their successful applications in chemical and engineering research, these designs have been virtually ignored in human factors engineering experimentation. This is a serious oversight since these designs, as well as the whole concept of response surface methodology, are particularly suited for research relating human performance to equipment parameters. A study of the effects of three densor-display variables on the ability to recognize targets on a display is used to describe some of the valuable features of the central-composite design and to illustrate some of its advantages and disadvantages for human factors engineering research.