What Is HCI?

Human-Computer Interaction (HCI) is what is responsible for presenting the material on this web page to you in such a comprehensive manner. It is how you tell your computer that you want to follow a link on a web page. In fact, it has provided you with every means you have of communicating with the machine sitting in front of you right now. It also reaches outside of desktop computers. Think of an ATM - that is a computer with which thousands of people interact with every day. The ease with which these people go about their banking transactions on these machines is testimony to the well-designed interface the ATMs support. HCI design also so has some unsuccessful projects. Many people's difficulty programming a VCR has become a type of international joke. HCI is the field that figures out how to best design a product so that its use is convenient and logical to the people using the machine.

HCI is more, however, than the design of software or hardware interfaces. It is designing what each one does when they interact, not just a go-between. This distinction is what makes HCI such a challending academic field. It is just as much the study of people as it is the study of computers. People are complex; predicting what everyone will do in a certain situation is next to impossible. And yet that is exactly what scientists in the HCI field have to do.

According to Terry Winograd, a Stanford University professor, the ultimate goal of HCI is to reach Fluent Interaction. Consider the following analogy. When some is fluent in a language, when they want to communicate something to another person they don't consciously think about the words they use to convey their ideas; they simply think about what they are trying to convey and say the words necessary to that goal. People speaking a second language, however, in which they are not fluent, have a very different situation. Their conscious focus is on the words themselves - the correct vocabulary, what grammar to use - and this distracts them from their primary goal. The ultimate pinnacle for HCI is to create the fluent atmosphere, where users didn't have to think about what menu to choose, or which mouse button to click, but could naturally and fluently perform the necessary actions to achieve their goal.

HCI Dimensions

In a report written by Carnegie Mellon to propose an introduction of HCI into their Computer Science Department, the principles of of an effective system are laid out as follows:

What tasks are to be performed by the system is central to system design. Determining and designing the system for everyday, frequent tasks is not enough. Occasional tasks, exceptional tasks for emergency conditions, and repair tasks to cope with errors also have to be discovered, which requires HCI research in order to determine the tasks and enhance the performance of the tasks.

Understanding the humans who use the machines is also central to HCI design. Researchers have to, in effect, predict what people will do in a number of common situations. For example, on which menu will the user intuitively look for the "Select All" command? Additionally, things such as short-term memory, attention span, color vision, peripheral vision, and organizational contexts come into play. For example, the limitations of human short-term memory has caused the neccesity of organizing commands into menus.

Finally, computer software has a large impact on design. The system has to have the components necessary to perform the functions appropriate for the software in use. The mouse, for example, is a very appropriate element for desktop, personal computer use; it can be used to point and click, or draw, etc. For working on a vertical wall, however, such as a chalkboard, a mouse is hardly appropriate and is practically unusable - it would be very uncomfortable to scroll a mouse along a vertical surface for a long period of time.

These three sub-areas of HCI connect in both directions. All three influence the others and, in turn, determine the principles of HCI design.

To gain better insight into the world of HCI, read our case study of a project at Stanford, The Cardiovascular Biomechanics Research Lab, and a brief listing of some of the things that are happening around the world. We have also provided a listing of Stanford's current HCI projects.

Human-Computer Interaction in the School of Computer Science. Ed. Bonnie E. John, et al.
Terry Winograd, Interview, 9/12/01