<center><span class="normal"><span class="black"><b>Human Computation </b> </span>
</span></center>
<span class="normal">
<br>
Most of my time is spent inventing novel techniques for utilizing the
computational
abilities (or "cycles") of humans.
</span><span class="small"><br><br> </span><span class="normal">
One family of techniques is <b><a href="http://www.recaptcha.net" class="normal">CAPTCHA</a></b>, automated
tests that humans can pass but that current computer programs cannot.
CAPTCHAs take advantage of the power of human cycles in order to
differentiate people from computers, and have many applications in
practical security. The previous results of my joint work with Manuel Blum, for instance, are
used by Yahoo! to ensure that only humans obtain free email
accounts.
</span><span class="small"><br><br> </span><span class="normal">
Another family is exemplified by my work on
<b><a href="http://www.espgame.org" class="normal">
The ESP Game</a></b>.
ESP is a seductive online game -- many people
play over 40 hours a week! -- and when people play they help determine the
content of images on the Web by providing meaningful labels for them.
If the game is played
as much as other popular online games, all images on the Web can be
labeled in just a few weeks. Attaching proper labels to all images on the
Web would allow for more accurate <a href="http://www.peekaboom.org/cgi-bin/phetch/search-esp" class="normal"><b>image
search</b></a>, would
improve the accessibility of Web sites, and would help Web browsers block
pornography. This approach to labeling images is simple but novel: rather
than using computer vision techniques that don't work well, we
encourage people to do the work for us by taking advantage of their desire
to be entertained. The ESP Game has collected over 10
million labels for images on the Web.
</span><span class="small"><br></span>
