Some Economics of User Interfaces

I examine the incentives for software providers to design appropriate user interfaces. There are two sorts of costs involved when one uses software: the fixed cost of learning to use a piece of software and the the variable cost of operating the software. For example menu driven software is easy to learn, but tedious to operate. I show that a monopoly provider of software generally invests the ``right'' amount of resources in making the software easy to learn, but too little in making it easy to operate. In some extreme cases a monopolist may even make the software {\it too\/} easy to learn.