Penn State Learning Design Community Hub

There's been a good discussion on the W3C Accessibility list about Captchas and accessibility with some great ideas.

Captchas are those images of distorted numbers and letters that you have to enter into registration forms. These are used to prevent form robot spamming on the theory is that only a human could visually process the information and enter the correct information. The accessibility problem is 1) That are not ALT Tagged because then the robot would know what to enter and 2) the actual images are so distorted that a low vision person still might not know what's in them. This is why the new WCAG 2.0 guidelines include references to making sure Captchas (or their equivalents) are accessible

What are some ideas of making a form human friendly but still fooling robots? Some ideas included

* The classic answer is to have both Audio and Graphic captchas - in both cases rotating items randomly. But this is multimedia intensive.
* Include a simple question humans can answer, but not robots. The best class are simple math problems like "What is 10+3"? Questions and answers should be rotated randomly
* Avoid Captchas altogether, but design your form with key hidden fields which will serve to distinguish robots from humans
http://nedbatchelder.com/text/stopbots.html

The last article points out that although a robot could be programmed to circumvent anything, robot programmers (like car thieves) will more likely focus on the "low hanging fruit".