in flagrante delicto — caught in the act
Here’s a quick lesson on the importance of watching people while they use your products in the context where the products are used.
Some time ago, I was leaving the movie theater in the mall when I passed by some people using the touch screen information kiosk. There were three or four of them huddled around the screen — talking, pointing, touching — trying to find something.
Two of them in particular were the primary drivers of the touch screen. Frequently, they would both touch the screen at the same time in different places, leading to random results; the next page that displayed was different than what either person had touched.
Unfortunately, this screen was built to operate on a single touch. If two people touch it at the same time in different places, it records a touch at the midpoint of those touches. The two people at the screen that day didn’t know it but their information retrieval goal was subverted by the screen’s designers.
More recently, I was using a Coke touch screen vending machine when my nephew came over and started playing with it at the same time. The same thing happened; the screen didn’t handle multiple touches, and the result was neither my nephew or I got what we expected.
Two lessons here. First, single-touch screens are obsolete. If you’re building a touch-screen device, multi-touch is the only way to go.
Second, always watch people use your products in real situations. Unless you sat and watched that kiosk all day, you would never know that single-touch was causing so many problems.
No usability test or lab setting can reproduce the infinite variety of reality.