I know I’m extremely late to the party, but I just got myself an iPod Touch. It is quite impressive, and one of the major aspects of the user interface that I love so much is how intuitive the touch-based action gestures are. Being intuitive is hard to define, but I like to think that if something is intuitive it appeals to common sense.

The touch controls are something that have been highly touted and are well-known at this point. In order to zoom in on a location in Maps, a photo, or a web page in Safari, you put two fingers around the location you want to zoom in on, then you bring them closer together. This is known as the “Pinch.” Conversely, to zoom out, you spread your fingers apart (the “Anti-Pinch”?). Finally, to move around the map, you simply press your finger against the screen and move it in the direction you want the map to go.

This is an example from the Mobile Safari web browsing application:

These actions seem so intuitive that they elicit a reaction of “Well, obviously!” from many people. However, this is not one of those times when common sense would seem to point to these gestures. This seems to be more a function of hindsight bias (hindsight is 20/20) than anything else.

For example, the simple “pulling” action to scroll around in the Maps application is the most intuitive, gestures. This is so intuitive, in fact, that I find myself trying that with other map programs. Google implemented this first with their web-based Map application (so this was not an Apple invention). However, other companies have simply not caught on – MapQuest, for example, does not implement this feature. My GPS (a TomTom Go 720) has not, either. When I want to make sure the route it is giving me is correct, I want to be able to grab the map and scroll to get a better sense of where the route is taking me. Instead, the GPS thinks I tapped the screen, which brings up a different part of the interface. I am left unsatisfied.

The zoom controls are another aspect of the interface that are intuitive. I don’t find myself trying to pinch and anti-pinch on other interfaces. Instead, I am satisfied with a zoom bar (pictured below) or using a scroll wheel to zoom in and out.

The biggest reason for this is that zooming on the iPhone/iPod Touch requires two fingers, and there is no way to emulate that using the input devices available to modern computers. However, the iPod Touch pulls it off quite nicely, and it is continually impressive to show off. The master, Steve Jobs, certainly impressed the crowd when he introduced the iPhone:

What this all boils down to is ease of use, which can be split into two parts. One is ease of learning, which is what intuitiveness is all about. A shallow learning curve for these gestures means they are grasped easily. This then improves information retention, the second part of ease of use. Users remember what action to perform to reach a desired state, and they perform the action admirably.

Compare this with a new computer user learning Copy and Paste. Click + Drag over text, choose one of 50 different commands that let you copy (right-click, the Copy button in the toolbar, the Edit menu, a keyboard shortcut…) and then repeat for paste. The learning curve is somewhat steep, and the retention of information is not all that great.

The iPhone/iPod Touch, however, gets it right.