More wrong assumptions revealed themselves during these courses. For example, the “+” and “-” markers on the map are not intuitive either nor is the concept of zooming in and out. How are you supposed to understand that pressing these buttons still shows the same map but at a different scale and not an entirely different picture instead? Again, when I took a moment to think about this, I realized again how completely confusing that could be. And again I kicked myself. But contrast this to an entirely different setting, San Francisco, where some friends recently told me how their five year old went up to a framed picture in their living room and started pinching at it with his fingers, the exact same gestures one would use on an iPhone to zoom in and out of a picture. “Broken, broken” is all the five year old said after that disappointing experience.

(Source: poptech)