Human-based computation is when people use their brains to complete tasks that computers can't do very well. An example of this is if a computer program is trying to recognize objects in a photo, it might not be able to do it very well. People, however, can look at the photo and identify most of the items. So, programmers can create a website or app where people can look at the photo and identify the objects. The answers they give will help the computer program to become better at recognizing the same objects in photos in the future.