A taller iPhone: ergonomically problematic?

In recent weeks, rumors of an iPhone with a larger screen have resurfaced. A forum post on the Verge, subtly substantiated by Apple insider John Gruber, imagined how Apple could increase the device’s screen size without expanding its actual footprint. By sliding the earpiece up and shrinking down the home button, Apple could pack in more vertical pixels, transforming the iPhone’s screen from a squat 3:2 to something nearer 16:9.

Now, I’m all for a larger iPhone screen. The current version does feel small. But this particular idea has its problems.

My own misgivings have to do with button ergonomics. The current iPhone’s home button is already tricky to press, particularly when the device is held with one hand. If I grip the phone securely, my thumb can’t reach the home button. I’m forced to shimmy the iPhone “up” my grip, balancing it on my index finger. While my thumb stretches, I lose its stabilizing anchor point. The combined effect? It feels as if the phone wants to flip over my fingers and tumble to the ground.

And what if, as the rumors suggest, the home button gets smaller and slides further down to accommodate a taller screen size? Well, in short, a things get worse:

• First, as the home button moves down, hitting it comfortably will mean holding the iPhone even higher in my hand. More weight will hang out into the air, making the device less stable.
• Second, a smaller home button would be a harder target to hit. My thumb would take longer to find the button. This would leave the phone unanchored (and vulnerable to drops) for longer stretches of time.
• Third, shifting the home button downward would mean that my thumb presses down slightly closer to the device’s bottom edge. As with a lever or see-saw, moving the contact point away from the fulcrum results in more movement. It’s tough to maintain a firm grip on a moving object.[1]
• Finally, with the home button relocated near the phone’s bottom, there’s a greater chance that my thumb will unexpectedly slip off the edge. Suddenly, I’ve lost that anchor point completely. My reflexes might not fire quickly enough to tighten my grip—and prevent the phone from flipping backwards, out of my hand.