The benefits of the object-action syntax are that users do not have to remember what actions are valid at what time for which objects. First, select an object. Then only those actions that can be performed with that object are available. Unavailable menu bar actions are grayed out if they are not available for the selected object. A pop-up menu only lists available actions for the object.
Key Idea! Consistent implementation of object-action syntax allows users to learn the relationships between objects and actions in the product. Users can explore and browse the interface by selecting objects and seeing what actions are available.
Use Real-World Metaphors
Real-world metaphors allow users to transfer knowledge about how things should look and work. Today’s home computer comes equipped with a fully functional telephone, answering machine, and fax machine. How do users interact with these programs? They shouldn’t have to learn anything new, since most users already know how to use these devices.
Figure 5-6 shows the interface for my computer’s telephone system. Guess what? It looks like a telephone answering machine! It didn’t take me very long at all to figure out how to use the telephone or answering system. I didn’t even have to look at the brief documentation that came with the product. The same thing happens when users first see a Personal Information Manager, or PIM, such as Lotus Organizer. People know how to use organizers and Day-TimersTM already, so they have the experience and also have certain expectations about how an appointment organizer, address, and phone book should work.
Lotus Organizer Version 1.0 used an icon of an anchor to represent the Create Link action (see Figure 5-7). This was not a very intuitive icon to use. Next to the anchor icon was an icon of an axe. What action did this button perform? You wouldn’t guess—it represented breaking a link! How do the visual icons of an anchor and an axe represent these two related actions? Not very well. For the past few years I have used this example of inconsistent metaphors and poor icon designs. None of my students could figure out what these icons meant. Well, Organizer version 2 fixed this metaphor faux pas by using icons of a chain of links and the chain being broken to represent these actions (see Figure 5-8). I’m glad Lotus finally listened to me and (I’m sure) other designers and users about these obtuse icons!
Key Idea! Be careful how you choose and use interface metaphors. Once you have chosen a metaphor, stick with it and follow it consistently. If you find a metaphor doesn’t work throughout the interface, go back and reevaluate your choice of metaphors. Remember—extend a metaphor, but don’t break it.
Use Progressive Disclosure
Users should not be overwhelmed by what they can do in a product. You don’t need to show users all of the functions the product offers. The best way to teach and guide users is to show them what they need, when they need it, and where they want it. This is the concept of progressive disclosure.
Some software programs offer graduated menus for users to choose from. User can choose simple menus that offer only common actions and function for casual use. After they feel comfortable with the product, or if they have a need for more sophisticated product features, they can choose to use the advanced menus. The key is that users are in control and they choose how much of the program and interface they see and work with.
New interface technologies such as wizards and assistants use progressive disclosure to guide users through common tasks. Wizards step users through tasks in a progressive manner where each step is simple and meaningful for even casual users.
Key Idea! Always provide easy access to common features and frequently used actions. Hide less common features and actions and allow users to navigate to them. Don’t try to put every piece of information in one main window. Use secondary windows for information that is not key information.
Promote Visual Clarity
Apply visual design principles of human perception I discussed in Chapter 4, such as grouping items on a menu or list, numbering items, and by using headings and prompt text. Think of information on the screen in the same way as information you would present in any other medium.
The general principles of organization, continuity, gestalt, and so on should be followed. Most programs present too much information at one time on the screen. This results in visual clutter and users don’t know where on the screen to look for information. Information should be presented with some priority and order so users can understand how information is organized on the screen. Remember the old adage, “form follows function.” Some of these graphic principles are discussed in more detail in Chapter 13.
Avoid arbitrary groupings, distinctions, and other elements that seem to provide organizational information, but really don’t. Figure 5-9 shows a window layout with haphazardly organized graphic objects and text, resulting in a “clown’s pants” effect (from the Yale C/AIM WWW Style Manual, http://info.med.yale.edu/caim/stylemanual). This visual disorganization impedes usability and legibility, and users cannot browse or search for information in an orderly fashion.
Figure 5-10 shows a similar window layout using a carefully organized grid containing both graphic objects and text. The visual organization improves usability and legibility, allowing users to quickly find information they are looking for, resulting in increased confidence in their ability to use the information effectively.
Key Idea! Graphic artists and book designers are skilled in the art of presenting information using the right medium and then designing the presentation of that information appropriately. These skills should be represented on the user interface design team.