As preface, I used to teach interface design. My passion was still learning technology (and has been since I saw the connection as an undergraduate and designed my own major), but there’re strong links between the two fields in terms of design for humans. My PhD advisor was a guru of interface design and the thought was “any student of his should be able to teach interface design”. And so it turned out. So interface design continues to be an interest of mine, and I recognize the importance. More so on mobile, where there are limitations on interface real estate, so more cleverness may be required.
Stephen Hoober, who I had the pleasure of sharing a stage with at an eLearning Guild conference, is a notable UI design expert with a speciality in mobile. He had previously conducted a research project examining how people actually hold their phones, as opposed to anecdotes. The Guild’s Research Director, Patti Schank, obviously thought this interesting enough to extend, because they’ve jointly published the results of the initial report and subsequent research into tablets as well. And the results are important.
The biggest result, for me, is that people tend to use phones while standing and walking, and tablets while sitting. While you can hold a tablet with two hands and type, it’s hard. The point is to design for supported use with a tablet, but for handheld use with a phone. Which actually does imply different design principles.
I note that I still believe tablets to be mobile, as they can be used naturally while standing and walking, as opposed to laptops. Though you can support them, you don’t have to. (I’m not going to let the fact that there are special harnesses you can buy to hold tablets while you stand, for applications like medical facilities dissuade me, my mind’s made up so don’t confuse me :)
The report goes into more details, about just how people hold it in their hands (one handed w/ thumb, one hand holding, one hand touching, two hands with two thumbs, etc), and the proportion of each. This has impact on where on the screen you put information and interaction elements.
Another point is the importance of the center for information and the periphery for interaction, yet users are more accurate at the center, so you need to make your periphery targets larger and easier to hit. Seemingly obvious, but somehow obviousness doesn’t seem to hold in too much of design!
There is a wealth of other recommendations scattered throughout the report, with specifics for phones, small and large tablets, etc, as well as major takeaways. For example the implication from the fact that tablets are often supported means that more consideration of font size is needed than you’d expect!