At yesterday's Apple event "Back to the Mac", the point was stated and reiterated that they opted not to make the laptop screen a (multi) touch interface. The reason? ergonomics. After a while, your arm gets tired. Then after a while, your arm wants to fall off, Steve Jobs said.

I wonder if he was spouting party line or he actually believed that ergonomics was a valid reason to detach the interface from the thing being interfaced. I know I don't.

If the iPhone, iPod, and iPad proved anything with the touch interface, it's that a direct touch interface is incredibly natural. My three year old knows how to operate my iPod Touch, but I didn't teach him. In contrast, I spent some time introducing him to the idea that when you move this thing (the mouse), this other thing up here on the screen moves (the cursor). And then, when you click on this button, it does something. He didn't get it. A disembodied, foreign, two-step process will never beat a direct correlation to a natural process.

The other day, a coworker noted that after working with an iPad for a week, he started touching the monitor attached to his laptop. He's been using computers for a long time. Years of experience with mice and trackpad (even multi-touch gesture supporting trackpads) undone in a week. Why? Because people use their hands to manipulate what they see by touching it.

Do I buy the fatigue argument? You bet.

Unlike the iPad, laptop screens are inherently vertical. Making them horizontal, or more horizontal, would result in a lot of time spent looking (further) down, which results in bad posture and fatigue. And of course, touching a deeply inclined screen would just tip the laptop over. The reason it's ok for the iPad to rely on a touch screen is that it is not aimed at extended operation with extensive interaction. Reading a book or watching a movie takes time, but not much interaction. Productivity on an iPad basically requires a horizontal physical keyboard or a lot of intelligence in the software being interacted with, such that complex tasks can be done with little interaction. Having to physically support the thing while using it, or craning down over it to use both hands, is less than ideal, especially for extended interaction. (Full disclosure: I don't own an iPad, and have used one very little, but I have both an iPhone and iPod Touch)

I'm curious what people that have the iPad stand and keyboard think about the usability of the device while fully docked. Did they abandon the touch screen for a mouse or trackpad? If so, did they completely abandon it?

It seems to me the debate isn't over yet. Natural interfaces are a huge win for usability, but we apparently still need to learn how to bridge the gap to make them a huge win for productivity. I hope Apple and others are not content to leave the discussion at "it can't be done; bad ergonomics".