Recent innovation in the mobile phone market has introduced many new ideas around user input mechanisms (e.g. touch and speech), UI model, as well as output (e.g. new types of displays and audio).
When designing digital products, it is important to find the right balance between these three aspects. This might seem somewhat obvious, but most of the newer mobile phones have not done this well. Many companies just slap on touch, rather than designing the touch user experience from the ground up.
To understand this we have to take look at products where touch technology has been used for a long time; public vending machines. People that need to be able to buy tickets on vending machines range from 8 year olds to 80 year olds. That is why the design of the user interface for these products requires extra attention. Users should be able to use the product quickly without any prior training. When you walk up to the device it is immediately clear what the steps are; select your destination, select the type of ticket, and pay. This is called a “walk-up-and-use” interface.
Here you see an example of one of these ticket vending machines for the Dutch Railways. There also is an online demo of this walk-up-and-use user interface. http://webdemo.ns.nl/webdemo.e2000/
Touch screens are a great match to the walk-up-and-use interface model. After all, all complexity is removed, because there is no separation between the screen and the input, as you have with a d-pad, mouse, or hardware buttons.
Choosing for a touch screen (at least on a small screen) indirectly forces simplification of user interface. By requiring larger target sizes (since our finger tips are larger than mouse pointers), there is room for fewer objects and controls on the screen. Designers have to think even more carefully about how to use the precious screen “real estate” so as not to overcrowd the interface. The user has to be 100% clear about what will happen when they actually touch the screen.
Essentially the iPhone is designed as a walk-up-and-use interface as well. Everything is only a couple of taps away, only the most important functionality is included, everything you can do is clearly visible on the screen and screens have clear instructions and most icons have labels for what they mean and do. Also the multi touch functionality for things like scaling and scrolling becomes obvious once you understand the capabilities.
In addition a large screen, with a high resolution, accommodates for large hit areas and labels in a small font.
There are disadvantages with this user interface model as well. Although everyone can use and learn the functionality quickly, there is not much room for users to get better in a skill and acquire a certain level of mastery. Also, the walk-up-and-use UI model is not the only model that can be paired with a touch user interface. Sometimes it is the design goal is to create an element of discovery in the user experience, for example in games. In this case it might be desirable to choose a UI model that encourages exploration, rather than ease of use.
When considering some of the other mobile products that have come out recently, there is not such a logical partnership between the input mechanism (touch) and the user interface model and the output. For example:
- Windows Mobile 6 phones, for example from HTC, utilize several different input methods, ranging from d-pad, stylus to touch. The user interface model needs to accommodate all these different inputs. Windows Mobile phones are originally based on the desktop metaphor (i.e. start button and windows with close boxes). Users have to switch input type as well as mental model when using different functionality throughout these products.
- The Blackberry Storm essentially is not that much different from other Blackberries, except touch was added to it. Blackberries are devices where efficiency is important. It is okay for users to invest in learning the system in order for them to become more efficient. Once you have invested this time, you don’t want to relearn everything when you upgrade to the Storm. So RIM decided to stick to many of the intricacies of the Blackberry UI model, but then also add touch.
RIM did add an innovative input mechanism to the device called ClickThrough. There is a distinction between touching the screen and actually pressing down on the screen. However they only use it to make typing feel more natural. There is a missed opportunity to align this input method with an efficient UI model. For example they could have used touch for the primary action (open) and press down for other contextual options (copy, share, etc.). - The T-mobile G1 is specifically designed with touch in mind. However it is essentially a desktop computer with touch. It included many PC concepts, such as a desktop and menus where all the commands are hidden from view.
- Nokia also had a lot of UI legacy that they need to reconcile with their d-pad designs. Nokia’s phones (for example the Nokia 5800 XpressMusic) often have obscure icons with no labels, which requires users to learn them first. This might be fine when your phone has a d-pad and you get a tooltip that explains the icon, but for touch you need to understand it before you tap it. The same applies to Palm Pre.
In conclusion the careful balance between input, UI model and output is essential for any design. Although touch is trendy, it will only get you so far. When you do not design a user experience from the ground up, with touch in mind, you will only scratch the surface of what touch has to offer.