When did we start being concerned with usability? Some will say that such concern is part of being human: cavemen worked their stone tools to get them just right. Interaction design mattered even then. But the field of usability research really came into being when the tools we used started to run up against our cognitive and physical limitations. And to avoid hitting literal, as well as psychological, walls, it was the aviation engineers who started to think about usability seriously. While cars were becoming ever more sophisticated and trains ever faster, it was the airplanes that were the cause of most usability problems around WWI. Cars were big, but didn’t go very fast or had a lot of roads to travel on at the turn of the century. In the first decade of the 20th century, there were only 8,000 cars total in the U.S. traveling on 10 miles of paved roads. In 1900, there were only 96 deaths caused by the automobile accidents. Planes were more problematic. For one thing, the missing roads weren’t a problem. And a plane falling out of the sky in an urban area caused far more damage than a car ever could. Planes…