Designed for Use, 2nd Edition

Accidental Input

Some time ago, I switched from a simple pen-and-paper list to an application on my cell phone for grocery checklists. Pretty quickly, I noticed that I forgot to buy two or three items every time I went shopping. Further investigation showed that I didn’t really forget these items as much as accidentally remove them from my grocery checklist. While holding my phone with one hand and putting an item into my shopping cart with the other, I would often inadvertently touch the phone’s screen, accidentally marking an item as “done.”

Similarly, when friends and I played a Kinect^[76] game for the first time, the game would constantly pause for no apparent reason. We finally figured out that a person behind the players was leaning against ...