Good Interaction Design:
Electromechanical object, such as a radio say, links its physical mechanical components to its electronic elements in a fairly direct manner. When we turn the dial, our fingertips and muscles can almost “feel” the stations being scanned.
Computers, however, distance the relation between hand, keystrokes and screen image, and what’s happening inside the computer, is usually much less direct. Our physical world and the computer’s virtual world seem miles apart.
Thus a clear mental model of what we’re interacting with is needed. HyperCard, for instance, an early scripting system on the Apple, had a very clear mental model, a stack of cards: a precise analogy of what and how the program worked. It was obvious to its users that in effect they
were flipping through a stack of cards: everything about the
design reinforced this metaphor.
A well-designed system has reassuring feedback, on a keyboard, for example, we can tell what we’ve just done because not only do characters appear on the screen but we can feel the travel of the key itself and hear the little click it makes.
Navigability is also essential, particularly with things that are primarily on screen. You need to know where you are in the system, what you can do there, where you can go next, and how to get back. The Star and Macintosh interfaces were very influential in this way. The menu at the top of the screen lays out all the possibilities; it’s clear how you access them and what will happen when you do.
Consistency is as important. A certain command in one part of the system should have the same effect in another part. An example, again from some time ago, was Apple-works, one of the first integrated office programs on the Apple II. It was the time of green “ransom-note” characters on a black screen, and limited functionality. Yet, Apple-works was beautifully, satisfyingly, consistent. You knew exactly what to do. A command in the database did exactly the same in the word processor; wherever you were, the escape key took you back up a level.
When we interact with everyday artefacts, such as a car, we don’t spend too much time thinking about the interaction: we think about where we’re heading and what we want to do