Chapter 10 -- Good User Interfaces Are Visible | Developing User Interfaces for Microsoft Windows

Chapter 10

A user interface is visible when a user is able to figure out how to accomplish tasks just by looking at it. With a typical visible user interface, a user is able to perform tasks by making selections in the menu bar and dialog boxes and by manipulating objects on the screen with the mouse. Visible features don't require knowledge of special keyboard sequences or mouse interactions or any other mechanism that isn't visible on the screen.

So what specifically does it mean for a user interface to be visible? When a user interface feature is visible, its existence and functionality are obvious by simple inspection. A feature's existence is obvious by simple inspection when one of the following phenomena is true:

The feature appears directly on the screen, such as a command button or a hyperlink.

The feature appears on the screen when the user clicks on a standard drop-down interface, such as a menu bar or a combo box.

The feature is suggested when the mouse cursor passes over it, such as a sizeable window frame or a dynamic window splitter.

A feature's functionality is obvious by simple inspection when it meets one or more of the following requirements:

The functionality is clearly suggested by its visual attributes, such as a command button or a sizeable window frame.

The functionality is obvious with simple experimentation, such as the tools in a paint program.

The functionality is understood with the help of a tooltip, such as a toolbar button.

The functionality is visible and understood because of standards or convention, such as the behavior of check boxes and radio buttons, the double-clicking of a desktop icon, or the single-clicking of a hyperlink.

The functionality is visible and readily understood by common sense or real-life experience, such as a calendar control or the buttons in the Calculator utility.

The functionality is not visible on the screen at all but is standard enough that it is understood by users, such as moving a window by dragging its caption bar. In this case, while the caption bar appears on the screen, there is no visual indication that the user can move the window by dragging the caption bar.

While a modern graphical user interface such as the one provided by Microsoft Windows is highly visual, not all the user interface elements of a typical program can be figured out by inspection alone. You must have some basic knowledge about how graphical user interfaces work to perform even the simplest tasks. Consider a program's menu bar. While the menu bar is visible on the screen, to use it you have to understand why you need to use a menu, how to recognize a menu bar, how to pull down a menu, and how to make a selection. Without this basic knowledge, you can't do anything with a menu bar. In fact, menu bars would not be appropriate in environments where the user cannot be assumed to be a computer user, such as in a walk-up kiosk. But for normal Windows programs, using the menu bar is so basic that even the most beginning user (with, say, more than an hour's experience) can be assumed to know how to use a menu. This basic knowledge makes the menu bar a highly visible, hierarchically organized catalog of a program's features.

Clearly, there is more to making a feature visible than simply displaying it visually on the screen. The user not only has to be able to see it but also has to be able to understand it. No matter how artistic a feature's visual appearance is, if the user doesn't understand it, it really isn't visible. The understanding can come from the user's knowledge of the real world, the user's common sense, the user's basic knowledge of graphical user interfaces, or completely from the feature's visual properties. One way or another, a feature is visible if a user with basic graphical user interface skills can easily figure out how to use it just by looking at it.

TIP
There is more to making a feature visible than displaying it visually on the screen. The user has to be able to understand it.

Visible user interfaces often result in what is called a noun-then-verb form of interaction. You see something (the "noun" in the construction above) that you want to manipulate on the screen, you select it, and then you perform some action (the "verb"). Visible user interfaces can also be viewed as being object-oriented in that you select an object and then change its properties or perform commands.

A visible user interface is similar to an intuitive user interface (which, by the way, should really be called an "intuitable" user interface to reflect that fact that the user, not the interface itself, is doing the intuiting). A user interface feature is intuitive when it meets all the criteria below:

The feature is visible as defined above, not counting the case in which a feature is understood only because it is standard.

The feature has visual or functional attributes that are consistent within the program and with other programs.

The feature has visual or functional attributes that are consistent with real-life experience.

In other words, a feature is intuitive if its existence and functionality are obvious by simple inspection, if it is consistent with the user's real-world experience and other software experience so that the user can infer its meaning, and if it doesn't require the user to have any knowledge of the standards.

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Intuitive = Visible + Consistent - Standards

When describing a user interface, I prefer the terms "visible" and "consistent" over "intuitive" for two reasons. First, the "intuitive user interface" has become such a cliché that it hardly means anything anymore. Too many horrible, difficult-to-use user interfaces have been described as intuitive. Second, the terms "visible" and "consistent" are more specific and are both significant user interface attributes in their own right. Burying these two important design concepts in a single design cliché is a far less effective way of characterizing user interfaces.