When HCI Should Be HHI
G. Alan Creak · Information technology and disabilities · 1999
THE PROBLEM Human-computer interaction (HCI) has been defined (SIGCHI, 1992) as discipline concerned with the design, evaluation and implementation of interactive computer systems for human use and with the study of major phenomena surrounding them. In practice, most work in the area is directed towards the human-computer interface, with the object of determining how best to exchange information between a person and an inanimate entity, hardware or software, which will henceforth be referred to as the machine. Driving machines is not always simple, but computing practice over the last few decades, including significant advances in HCI over the later parts of the period, has taught us ways of making it comparatively painless. The result is seen in modern interfaces, which--when well designed--are very effective when the primary purpose of the interaction is to cause the machine to perform some specific task. For example, people interact with machines to make them do work, give information, and provide entertainment. Most machines are used in this way for most of the time. This is not the only case, though, and the situation is different if the machine is intended to mediate in communication between people, a category which include machines used for communication in rehabilitation systems. In such a context, the machine is being used to accomplish human-human interaction (HHI). This is a more demanding requirement. It is accepted that communication with a machine has to be conducted at a very low level of comprehension on the machine's part; despite efforts over the past decades, machines (even computers) are still stupid. In contrast, when people communicate with people, they try to convey ideas. Communicating with other people through a mechanical medium has nothing at all to do specifically with computers; it has, presumably, been of concern ever since writing was developed, and people have tried to set down their ideas in ways which other people could understand. This is far more difficult than direct communication, and even with our millennia of experience we have not found an easy way to use writing effectively and automatically. The problem is in encoding the ideas we wish to communicate in the comparatively narrow channel of words on paper, or other medium, without the expressive qualities of voice and gesture which characterise direct human conversation. The difficulties are magnified when even narrower channels are used; examples are the simple character channel of electronic mail, and the single switch channel of many rehabilitation devices. An example might help to clarify the distinction between HCI and HHI. The activity of an author writing text can be described in two ways, both of which are correct: AS WRITING TEXT: The object of using word-processing software through an interface embodying conventional HCI techniques is to transfer characters to a disc file so that they can be transported to some other machine and eventually be printed. To do so, the capabilities of the software are exploited to encode certain instructions to the printer. This communication between human and machine is by far the most common application of HCI methods. AS COMMUNICATING WITH PEOPLE: The object of writing the text is to convey ideas from the author's head to the reader's. This is not HCI--it is HHI. In communication using an unaided system such as speech or signing, encoding instructions to an intermediary is unnecessary. In each case, certain conventions are used to express feelings, add emphasis, imply comment on the primary message, and so on. In print in a conventional journal one might use devices such as italic text and page layout. In this journal, the _Guidelines for Authors_ (ITD, 1996) is more restrictive: Information Technology and Disabilities will be available as plain ASCII text only. ..... Underlining or italics should be indicated in the following way: _Information Technology and Disabilities_. …