Human Computation

A long time ago, I came across an interesting talk by Luis von Ahn, a young assistent professor in computer science at Carnegie Mellon University, on what he calls Human Computation. This concept basically revolves around a computational process which performs its function by outsourcing certain steps of its process to humans.

How does this work? Von Ahn uses the example of Captchas. A captcha is one of those “prove you’re human” tests which you have to take in order to register for various on-line services. They typically look like this:


Since various robots crawling the web can’t read the distorted text, they can’t register again and again for various on-line sites, while humans can. Basically, by using a test, which people can solve but which programs can’t, you can limit spam and various other nasty by-products of the Internet.

Luis von Ahn has been expanding on the concept of Captchas to explore how this idea of human computation can be used. He has started a project called re-captcha, which directs the human computation used in solving captchas (for instance to post comments on websites such as this) to read words in scanned books which the OCR programs scanning the text weren’t sure of. Thus, not only does the project prevent spam, it also directs the human computation towards a task which computers wouldn’t be able to solve on their own.

Von Ahn’s talk is fascinating, as it builds on the notion that all of the time and energy people spend on various trivial tasks such as recognizing words in captchas or playing solitaire actually can also produce relevant results as well. His main example is how he has developed small games around adding tags to images, getting people involved to play the games. In this way, the structure of these small games become a sort of algorithm for human computation.

I find this perspective on computer games absolutely intriguing. How can you utilize all of the energy which people pour into computer games not only to give them a fun, learning experience but also make the Internet a safer, better place? That seems like a worthy challenge for game developers.

One comment

  1. Pyramid Solitaire

    Wow now that would be something! Playing a game for a few seconds to show that you are real is a great concept, but have you seen the ones where you have to rotate and image upright as a captcha? That’s pretty cool too, sorry I don’t have a link handy, just came across it the other day and great article!

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