ESP game

The ESP game is a human-based computation game developed to address the problem of creating difficult metadata. The idea behind the game is to use the computational power of humans to perform a task that computers cannot (originally, image recognition) by packaging the task as a game. It was originally conceived by Luis von Ahn of Carnegie Mellon University. Google bought a licence to create its own version of the game (Google Image Labeler) in 2006 in order to return better search results for its online images. The licence of the data acquired by Ahn's ESP game, or the Google version, is not clear. Google's version was shut down on September 16, 2011 as part of the Google Labs closure in September 2011.

Image recognition is a task that is difficult for computers to perform independently. Humans are perfectly capable of it, but are not necessarily willing. By making the recognition task a "game", people are more likely to participate. When questioned about how much they enjoyed playing the game, collected data from users was extremely positive.

The applications and uses of having so many labeled images are significant; for example, more accurate image searching and accessibility for visually impaired users, by reading out an image's labels. Partnering two people to label images makes it more likely that entered words will be accurate. Since the only thing the two partners have in common is that they both see the same image, they must enter reasonable labels to have any chance of agreeing on one.

The ESP Game as it is currently implemented encourages players to assign “obvious” labels, which are most likely to lead to an agreement with the partner. But these labels can often be deduced from the labels already present using an appropriate language model and such labels therefore add only little information to the system. A Microsoft research project assigns probabilities to the next label to be added. This model is then used in a program, which plays the ESP game without looking at the image.

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