Building a user-derived interface

Abstract

Many human-computer interfaces are designed with the assumption that the user must adapt to the system, that users must be trained and their behavior altered to fit a given interface. The research presented here proceeds from the alternative assumption: Novice behavior is inherently sensible, and the computer system can be made to adapt to it. Specifically, a measurably easy-to-use interface was built to accommodate the actual behavior of novice users. Novices attempted an electronic mail task using a command-line interface containing no help, no menus, no documentation, and no instruction. A hidden operator intercepted commands when necessary, creating the illusion of an interactive session. The software was repeatedly revised to recognize users' new commands; in essence, the interface was derived from user behavior. This procedure was used on 67 subjects. The first version of the software could recognize only 7 percent of all the subjects' spontaneously generated commands; the final version could recognize 76 percent of these commands. This experience contradicts the idea that user input is irrelevant to the design of command languages. Through careful observation and analysis of user behavior, a mail interface unusable by novices evolved into one that let novices do useful work within minutes.

Maximizing the guessability of symbolic input

“…Although this improvement was not quite significant after 5 minutes, that the average immediate usability increased at all shows the power of using participants to improve even refined symbol sets [5]. Furthermore, after examining the immediate usability data, we believe S u could be improved even more by changing a few problematic symbols.…”

“…Prior studies [4,5] show that designers often supply only one command-line term per referent. But one term, no matter how "natural," results in guessability failures of 80-90% [3].…”

“…A proposed solution is "unlimited aliasing" [4], where the system makes the best guess at the intended referent in the event of an unrecognized symbol. Having multiple synonyms has also been recognized as a key to achieving high guessability in command-line interfaces [4,5].…”

“…the same symbol will have been used to indicate different referents. An example from the literature [5] is the email command "To Dennis" being proposed to mean "send a message to Dennis" and also "list messages sent to Dennis." Similarly, the same unistroke gesture may be proposed for "h" and "n" [7].…”

Exploring the design space of gestural interaction with active tokens through user-defined gestures

“…User-elicitation studies are a specific type of participatory design methodology that involves end-users in the design of gesture-sets [12,28,54]. Such studies have been used to design gesture interfaces of various types including multitouch gestures on small and large surfaces [2,10,11,22,25,32,57] and multi-modal interactions [28].…”