Input controls and social conventions

I have a pair of Samsung Level Over headphones that I use at work to listen to music. I got them as a holiday gift when I worked at Samsung Research. They’re fine; the sounds quality is decent, and it’s useful not to have to worry about wires (and the Bluetooth connection is quite solid). You can control playback by gesturing on side of the headphones; the ones I use the most are swiping to change tracks and double-tapping to play or pause.

I didn’t think much about the double tap gesture at first; it seemed to make sense, since it could in theory be easily to accidentally single tap the headphones, when, for example, adjusting them. A double-tap would make accidental activation a bit less likely.

But after using the headphones for months now, there’s an unfortunate conflict with a common social convention. If someone comes up and wants your attention but you’re in the middle of listening to something and can’t stop, you communicate that fact by looking at the person and double-tapping on your headphones. So the common convention for “I’m listening to something and can’t be interrupted” is that same as the controls for pausing playback so you can talk to the person. Oops.

The moral of the story? When designing gestural input (and input in general), you need to think about the usage context more generally, not just what the system can recognize reliably and what physical mapping makes sense in isolation.