There is a rather dismal article over at the New York Times, To Win Over Users, Gadgets Have to Be Touchable, by Claire Cain Miller. (I think my expectations are too high for the NYT, but that's another story.) The main idea of the story is that the current touch interfaces (thank you, Apple) are "natural" and we don't need to learn them, we know them already.
Unlike past interfaces centered on the keyboard and mouse, natural user interface uses ingrained human movements that do not have to be learned.
But this is not at all true. A lot of the things we do with touchscreens are the exact same things, conceptually, that we've been doing with GUI interfaces since 1984 (GUI, for those of you who have forgotten, stands for Graphical User Interface, meaning, a mouse, windows, file icons, folders, probably a desktop, in other words, not the text-only CLI, which is Command Line Interface).
If you want an app to launch on your iPhone, you touch it.
If you want an app to launch on your Mac, you touch it with your mouse, which is your onscreen finger. Technically you mouse over it and double-click it, but, it's the same concept. Your mouse cursor is always in the screen, your finger spends most of its time not physically touching your touch-device screen. Same thing.
I could go on, but let's look at text. If you want to select text on your iPhone, you hold your finger on it and expand or select the amount of text you want. If you want to select text on your Mac, you have to take similar direct action on the text with the mouse cursor, which may involve clicking (perhaps with the shift key) or click-dragging or double-clicking.
It is, again, the same basic concept.
In some ways, it is not "ingrained." Widespread literacy is a historically recent phenomenon, but I doubt the ancient Romans poked their finger at text on a scroll and expected anything to happen.
In other ways, it is ingrained, because by copying the concepts from desktop, GUI-based, operating systems, touch-screens were copying a computer front-end that tried to mimic our human interface with our real-world offices: files, folders, trash cans, and a desk (desktop). If you want to do an action on an item, you poke it with your mouse cursor.
I've seen many a touch-device running Windows, where the mouse cursor follows your finger. I cannot remember what these devices are, they may be airport check-in kiosks. (I am pretty sure some were.) Your finger is the mouse.
Of course if you have an iPad or iPhone and there are no buttons on it, well, what's left to try? Touch.
I am reminded of a scene in one of the Star Trek films (the one with the whales, and Chekov's famous line about "nuclear wessels"). Scotty sits down in front of a classic form factor Mac, and tries to talk to it like he would his futuristic computer. The current-day assistant looks confused, and then hands Scotty the mouse, saying "Try this." Scotty picks it up and tries to use it like a microphone. (Eventually he gives up and uses the keyboard, which isn't a realistic approach to what he ends up doing, but that's besides the point.)
Natural interfaces are learned. (We spend many years learning how to interact and interface with the real world and especially people.) They may be easy, but they are learned.
