Benefits of Evolving UI Styles

At the time of writing, Nokia is finalizing the UI style for its first 3G mobile handsets. This style, called Series 45, builds on the proven Navi-key and Series 40 interaction principles, borrows some graphical elements from the Series 60 UI style, and fixes the problems we encountered with our Navi-roller UI. It solves the unlabeled selection key problem by introducing three clearly labeled softkeys.

The familiar two-softkey Series 40 UI carefully morphs into three softkeys (see Figure 1.8), two of which perform like Series 40 options and back softkeys while the third, in the spirit of the Navikey, provides labeled direct access to the most needed dynamic functions. All the other control keys are inherited from the Series 40 UI style. This UI is introduced in the Nokia 6650 WCDMA phone and will gradually replace the Series 40 UI style in our most feature-rich mass-volume phones.

Figure 1.8: Series 45 UI style with three labeled softkeys.

User interface style evolution means gradual or incremental improvement in the UI style, as was the case when the original two softkey UI evolved to Series 30 and Series 40. Through controlled evolution, we can leverage an existing UI style and keep it competitive for a long time. Most of our UI design and development work today is evolutionary development.

Sometimes, as we've allowed, a clear customer need is driving a step in UI style evolution; it is more convenient, for instance, to read and write a full text message on the display instead of scrolling back and forth to see it in several chunks. At other times a technological development we want to promote nudges the UI in a new direction. For instance, improvements in display technologies and greater bandwidth in 2.5G and 3G wireless networks will justify new UI elements such as color displays, and these can then be leveraged for services like multimedia messaging. And sometimes it is a standardization body that is driving UI style evolution.

An evolutionary approach to UI development has practical advantages for the mobile phone manufacturer, too. Small improvements are easier, faster, and cheaper to implement than large ones. It is also easier to turn back, if the chosen solution is not well received on the marketplace.

Consumer benefits of the evolutionary improvement model are obvious. For example, replacing your phone with a new model is easier when the new model has some familiar characteristics (just imagine having to relearn the steering system and gearshift routines for every new car you drive). When we succeed in the evolutionary approach, that is, when we have taken the right steps, customers should see evolution as improvements, and not as disruptive changes. Watch any customer trying out a new phone-comments such as 'Oh, they changed the softkey functions' and 'This message editor looks funny' may sound a bit negative. We would prefer hearing 'Oh, so now I can do this, too!' and 'This is what was missing for text messages' instead. As most people already own a mobile phone in the developed markets, it has become extremely important to support replacement customers by providing a smooth evolutionary path from one product generation to the next. It is far easier for the customer to transfer from one UI style to a variant of the same, rather than to a completely new style.

UI style evolution takes several paths. The most straightforward one is to improve display technology, resolution, or color depth. Improvements of this nature will change the visual appearance of a UI style without changing the basic interaction logic. Shrinking the display size or resolution may have desirable effects on product cost and size, but downsizing visible content will displease users accustomed to better. As a result, the downsized product is typically offered to new customer segments instead of customers with the previous model.

Increasing display resolution pays off in two ways: (1) content, both textual and images, can be presented more sharply and clearly, and we thus increase legibility and appeal; and (2) more content can be shown on the screen. The first payoff is the biggest, however. The main usability issue is to reduce scrolling and support the read-ahead function, thereby rendering the features and applications faster and more convenient to use.

The prominence of display in defining small-screen UI style is very different from that with the PC; Windows or Macintosh GUIs scale automatically and perfectly whether you use a resolution of 800 x 600, 1280 x 1024, or 1600 x 1200. In the mobile device arena, however, the UI designer is not so blessed. A 96 x 65-pixel array is basically the smallest display you can use for a calendar view of one month while retaining at least some aspects of good visual design. Any time you have more pixels-say, 128 x 128-then you're all but obligated to use them, which means that you'll have to design new display layouts and probably tweak functionality (now that you can use proper headings, new icons, or scrollbars). For an example of what we mean, please refer to the two calendars depicted in Figs. 1.3 and 1.4.

The keypad can also be evolved. However, each UI style is built on central control keys, and modifying those may result in a completely new UI style instead of a variant. Changing them typically affects the interaction logic of the UI style, meaning that users must learn new skills for their phones, whereas keys dedicated to a more specific use, such as keys for mobile browsing, can be added, removed, or changed without fundamentally changing the underlying UI style.

It's always possible to vary key mechanics, though. This kind of change (e.g., replacing scrolling keys with a roller) doesn't have direct impacts on the interaction logic of the UI style, unless you introduce new functionality as we did with Navi-roller. But ergonomics play an important part in determining user experience, and if the control devices are changed they must also be evaluated-the old usage logic may not be in harmony with the new mechanics. As we defined it in the previous section, a UI style is made up of interaction conventions with specific UI hardware; changing one feature may not be possible without changing the other as well.

Working on creating a new UI style, or in our terms on UI style evolution, is a multidisciplinary task. UI style design requires competencies in interaction design, visual and graphical design, ergonomics, industrial design, end-user and usability research, market research, linguistics, localization, marketing, software implementation, competitor product analysis, and consumer trend analysis, to name just a few. Because of the evolutionary nature of UI style development, it also requires an understanding of both the company's product strategy and the existing user interface portfolio.