I finally replaced my ailing cellphone (held together by strips of yellow duct tape) with an iPhone. Which I like a lot. But I just noticed an oddity about the interface: The "flick" gesture on the iPhone that I use to scroll up and down pages has the opposite effect of the trackpad scroll feature on my MacBook Pro: To scroll down a long page on the iPhone, I put a finger on the screen and flick upward. In OS X, to scroll down a long page I put two fingers on the trackpad and move then downward. Either way is fine—in fact, I've been using the flick gesture on the iPhone for nearly a week now and hadn't even noticed that I was using a different gesture than the one I've been using on my computer for the last several years.

There are logical reasons behind either gesture direction. The iPhone's flick up corresponds to the realworld equivalent of moving a physical piece of paper up or down. OS X's flick down corresponds to re-centering a moving window over a static piece of paper (or, in a more recent/immediate precedent, corresponds to moving the on-screen elevator-in-scrollbar up or down in the supposed moving window over static object). I'm curious about the point at which the iPhone designers realized (and I'm assuming they did-they're apparently slightly intelligent and perceptive) that the conceptual models of the two spaces contradicted each other.

(I just realized that the iPhone's flick gesture might be modeled more on the "grabber" hand in applications like Photoshop (an application in which a user can use the grabber hand to move around iPhone-like, or the document window scrollbars to move more OS X-like. It's strange to watch the functionality of these virtual/spatial metaphors run into each other, like fast glaciers.)