Smart phones, touch screens and the “Gorilla arm effect”?

Question

I finally broke down and decided to get a smart phone for myself. While I find it really useful, I can't help wondering if any research has been done on the "gorilla arm effect" of holding a smart phone at a certain angle while trying to read something or going through an app. It won't be too prevalent if the phone screen is small enough that you can hold it with one hand and click with your thumb but having a smartphone with a large screen (4.3 inches), I can't help wonder what would be the impact as screens keep getting bigger (unless you have large hands).

Answer 1

Here you will find some papers mentioning the "gorilla arm effect". It's a pitty that some of them are not free to download.

Some more articles and references to this syndrome:

• Wikipedia's mentions within the Touchscreen and Gesture recognition articles.
• Jargon File's definition for Gorilla Arm (circa 1980).
• A paper on affectations of workers' body muscle and nerve compression by bad postures.
• An article from ZDNet about Windows 7 and the Gorilla Arm.
• And to sum it up, an extensive article by a design consultancy.

The last article defines the Gorilla Arm effect thusly:

“Gorilla arm” was a side-effect that destroyed vertically-oriented touch-screens as a mainstream input technology despite a promising start in the early 1980s.

Designers of touch-menu systems failed to notice that humans aren’t designed to hold their arms in front of their faces making small motions. After more than a very few selections, the arm begins to feel sore, cramped, and oversized—the operator looks like a gorilla while using the touch screen and feels like one afterwards. This is now considered a classic cautionary tale to human-factors designers; “Remember the gorilla arm!” is shorthand for “How is this going to fly in real use?”.

And finally:

Gorilla arm is not a problem for specialist short-term-use uses, since they only involve brief interactions.

So, as long as we keep having "short-term" interactions with our handhelds —or as long as they keep getting lighter—, this will not be a problem. The Gorilla Arm effect though is a nice reminder on how promising interaction patterns can go wrong.