The actual study is a 93-page long PDF document, and I sure won't cover every aspect of it. The summary posted on Nielsen's website highlights the most important findings, and there sure is some interesting stuff in there. In a nutshell, "iPad apps are inconsistent and have low feature discoverability, with frequent user errors due to accidental gestures. An overly strong print metaphor and weird interaction styles cause further usability problems."
Sadly, since I have no iPad, all I can do is look at my iPhone, which experiences many of the same problems.
For instance, one of the big problems uncovered by the study is that users had troubles with the fact that each application uses its own user interface, leading to lots of unexpected behaviour and undiscovered features. For instance, tapping on an image in any application can lead to any of five behaviours: nothing happens, it links to another page, it flips the image to reveal additional pictures in the same place, or it pops up a set of navigation choices.
The three main problems, according to Nielsen's study, are low discoverability, low memorability, and accidental activation. "When you combine these three usability problems, the resulting user experience is frequently one of not knowing what happened or how to replicate a certain action to achieve the same result again," Nielsen concludes, "Worse yet, people don't know how to revert to the previous state because there's no consistent undo feature to provide an escape hatch like the Web's Back button."
This has bothered me about my iPhone as well. Every applications has its own isolated user interface with its own UI paradigms and behaviour. The end result is that switching between applications can be incredibly jarring, as user interface elements are in a different place for each application - or nowhere at all.
The best example is probably Tweetie. Whereas most applications have a "reload" or "check for new messages" button or whatever somewhere, you reload Tweetie by dragging the message queue down for a short time, which will trigger the reload. I've had to point this behaviour out to many of my friends.
The study also contains a few guidelines for UI design on the iPad, and most of those can be applied to regular computers as well.
- Add dimensionality and better define individual interactive areas to increase discoverability through perceived affordances of what users can do where.
- To achieve these interactive benefits, loosen up the etched-glass aesthetic. Going beyond the flatland of iPad's first-generation apps might create slightly less attractive screens, but designers can retain most of the good looks by making the GUI cues more subtle than the heavy-handed visuals used in the Macintosh-to-Windows-7 progression of GUI styles.
- Abandon the hope of value-add through weirdness. Better to use consistent interaction techniques that empower users to focus on your content instead of wondering how to get it.
- Support standard navigation, including a Back feature, search, clickable headlines, and a homepage for most apps.
Especially the first and the last two points get much applause from me - for everything UI.
The iPad is coming to The Netherlands in July, and I'm really looking forward to finally getting my hands on one and playing with it. The reports on the internet have been quite positive and starry-eyed, approaching the mass hysteria surrounding the Nintendo Wii. I want to know what all the hubbub is about!
Oh, and bring back Platinum!