I’m at a Wave company retreat right now in a rented-out townhouse in DC, and my room was freezing last night. Tonight my coworker found the thermostat for our floor and I asked if she could turn it off.
“I’m not sure if there’s a way to do that,” she said.
It turned out that our thermostat was a Nest and Nest thermostats are totally inscrutable until you do a bunch of random things and one of them does something interesting.
If you do the obvious thing that the Nest affords and twist the edge (and I use “obvious” loosely here), you can control the temperature. But you can’t turn it off. The way you turn it off is by bringing up some kind of “main menu”, and the way you bring up the main menu is by pushing on the screen (which by the way is exactly not what you’re supposed to do on every other non-touchscreen device, like TVs or laptops). Of course, nothing lets you know that you can push on the screen—you just have to intuit that it works.
I have this problem with mobile apps too. Want to delete something from a list of entries? Maybe you should swipe right on it! Or swipe left and press the “delete” button that appears! Or long-swipe left because short-swipe does something else! Or maybe it’s a long press on the item to bring up a menu that includes “delete”? Or, alternately, you could tap on the “edit” text at the top of the list, then check off the item and tap the “delete” button that appeared out of nowhere. (I hope you noticed it!)
Whatever the answer is, the one thing that you can count on is that you’ll have no idea from just looking at the interface. People seem to have gotten completely carried away by the exciting new “user interface conventions” that mobile apps offer, and forgotten that your app needs to be understandable to someone who hasn’t memorized the currently-fashionable magic gestures du jour.