Computers have learned to make us jump through hoops John Naughton

The other day I had to log in to a service I hadn't used before. Since I was a new user, the website decided that it needed to check that I wasn't a robot and so set me a Captcha (Completely Automated Public Turing test to tell Computers and Humans Apart). This is a challenge-response test to enable a computer to determine whether the user is a person rather than a machine. I was presented with an image of a roadside scene over which was overlaid a grid. My "challenge" was to click on each cell in the grid that contained a traffic sign, or part thereof.