Games with a Purpose

Website Taps into Human Factor

Most online games promise players only entertainment and distraction. GWAP — a new site launched by scientists in Carnegie Mellon's — offers something more: a chance to make computers smarter.

Featuring what Professor (CS '03, '05) calls "games with a purpose," or GWAPs, each is a multi-player online game that is designed to be fun and accomplish tasks that are easy for humans but beyond the capability of today's computers.

"We have games that can help improve Internet image and audio searches, enhance artificial intelligence and teach computers to see," said von Ahn. "But that shouldn't matter to the players because it turns out these games are super fun."

The site now features four new games and a classic called the ESP Game. The first GWAP developed by von Ahn, the ESP Game displays images to two players who each try to guess words that the other player would use to describe the image. The game improves web image searches by generating descriptions of uncaptioned images. Google Inc. has licensed the game, which the company calls Google Image Labeler.

The new games are:

Matchin, a game in which players judge which of two images is more appealing. It's designed to eventually enable image searches to rank images based on which ones look the best;
Tag a Tune, in which players describe songs. The game gives computers a way to search for music other than by title — such as happy songs or love songs;
Verbosity, a test of common sense knowledge. This one will amass facts for use by artificial intelligence programs; and
Squigl, a game in which players trace the outlines of objects in photographs. The game will help teach computers to more readily recognize objects.
"Putting all of these games on one site, we hope to drive up traffic by enticing players from one game to try the others," explained von Ahn. "And we're going to be adding a lot of games. We have three more that we'll be launching in the coming months."

Having all of them together on the site also makes it possible for players to have a single sign-on and password, Top Player rankings and online chats, added von Ahn.

In addition to von Ahn, GWAP and the games have been developed by software engineers Mike Crawford and Edison Tan in Carnegie Mellon's Computer Science Department and School of Computer Science grad students Severin Hacker, Edith Law and Bryant Lee.

Winner of a 2006 MacArthur Foundation "genius grant," von Ahn is a pioneer in the field of human computation, which uses the Internet to tap human minds to accomplish feats that still befuddle computers.

"Human computation doesn't work unless you have people," concluded von Ahn. "That's why we've made the games on GWAP as fun as possible. We need people."