It's nice that you can tap-and-drag on your Mac's trackpad, swipe on your iPhone, or pinch on your iPad. These options offer a welcome change to the old keyboard-based approach to computing. But as gestures multiply, I've come to find them confusing, and I realize that rather than simplifying my use of computers, phones, and tablets, they make it more complicated.
Some of the gestures are simple and logical - the two-finger downward slide on a trackpad, for example, which you can use to scroll through long documents or webpages. Likewise, the two-finger tap that lets you display a contextual menu is much easier than pressing the Control key and clicking with a pointing device. (You can still right-click if you use a two-button mouse, of course.)
But deeper in the jungle of gesture controls, you get the two-finger-double-tap, the five-finger-reverse claw, and the six-finger-tap-drag-wiggle. All of these sound more like figure skating moves than like touchpad maneuvers, and they're too complex for me to remember. In addition, some are the equivalent of rubbing your belly and tapping your head simultaneously--a development unwelcome to users who aren't especially coordinated.
To be fair, OS X gives you good ways to learn how to use gestures. Open System Preferences, click the Trackpad pane (which appears only if your Mac is connected to a trackpad), and then click one of the three different tabs. Apple realizes that gestures are complicated, so it includes brief videos showing you how you move your fingers, and demonstrating what will happen when you do.
Going through the motions
Unfortunately the proliferation of gestures invites confusion, as does the fact that not all applications support them. I'm writing this article with Scrivener, an excellent text tool for creative writers. A two-finger tap in Scrivener brings up a contextual menu, and scrolling works fine; but most other common gestures don't do anything. This isn't Scrivener's fault; it simply illustrates that gestures aren't yet at a stage of acceptance where they apply to a huge number of apps.
It goes beyond just apps, though. Suppose I'm looking at a gesture-related webpage on Apple's site, aimed at developers. If I try to do the Smart Zoom gesture (difficulty level 6/10), by double-tapping with two fingers, nothing happens. I assume that this is because the content is in a frame, and Safari can't zoom just the content of the frame. Other gestures fail in other apps for similar reasons: Logically they should work, but a glitch prevents them from achieving the desired result.
With iOS, this gets even more complicated. In addition to various standard gestures--such as swiping an item to bring up a delete button--each app can introduce its own. A recent email app that I tried incorporates both long swipes and short swipes; but apparently, the developers and I don't agree about what "long" and "short" mean, as I found myself making too many mistakes. (Tap and hold an app to make it wiggle, and then tap the X icon to delete it--which is what I did with that app.) As for Twitter clients, some show a conversation if you swipe left; others show it if you swipe right; and still others do nothing when you swipe. Granted, most people use only one Twitter app, but it's a pain to adapt to a new one because gestures aren't standardized.
One hand doesn't know what the computer is doing
Apple doesn't provide a cheat sheet for iOS gestures, as it does in OS X in the Trackpad preference pane. So for the most part, since iOS apps generally don't have Help, learning the correct gesture for the each action depends on trial and error. (Some developers have websites that provide good help, but many don't.) It took me a long time to figure out how to untilt a map in Apple's Maps app; other apps have had me scratching my head (with three fingers) for far too long.
I've long been a fan of keyboard shortcuts, which have two advantages: They often use mnemonics (Command-C for Copy, Command-P for Print; but Command-V for paste...), and you don't have to take your hands of your keyboard. So gestures on a Mac often require more work.
Since you don't use a keyboard to control an iOS device, gestures are a logical approach, but it's too hard to find out which gestures do what, and to become proficient at the more complex ones. When a friend recently did the five-finger-claw (difficulty level 7/10) to go back to the home screen on my iPad, I was amazed!
To make computing easier on touchscreen devices, Apple needs to provide more information about gestures, developers need to stop trying to invent new "cute" gestures, and perhaps an Apple app demonstrating gestures--like the OS X preference pane--would make gestures easier to learn. But we don't need any more gestures, please. The ones we have are confusing enough.
In the meantime, I'll just remember my favorite gesture: Go outside, turn around three times, spit, and curse. Because you can't be too careful.