Luis von Ahn

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Luis von Ahn
Wikimania 2015 - Day 2 (18).jpg
Von Ahn at Wikimania 2015
Born (1978-08-19) August 19, 1978 (age 38)
Guatemala City, Guatemala
Residence United States
Institutions Carnegie Mellon University
Alma mater Carnegie Mellon University
Duke University
Doctoral advisor Manuel Blum
Known for CAPTCHA, reCAPTCHA, Duolingo, crowdsourcing pioneer
Notable awards MacArthur Fellowship (2006), TR35 (2007)[1]

Luis von Ahn (born 19 August 1978) is a Guatemalan entrepreneur and an associate professor in the Computer Science Department at Carnegie Mellon University.[2] He is known as one of the pioneers of crowdsourcing. He is the founder of the company reCAPTCHA, which was sold to Google in 2009,[3] and the co-founder and CEO of Duolingo, a popular language-learning platform.


Von Ahn was born in and grew up in Guatemala City, where both his parents worked as physicians and his family owned a candy factory.[4] He graduated from the American School of Guatemala in 1996. He received a B.S. in mathematics (summa cum laude) from Duke University in 2000,[5] and obtained a Ph.D. from Carnegie Mellon University in 2005 under the supervision of professor Manuel Blum. In 2006 he joined the faculty at the Carnegie Mellon School of Computer Science.


As a professor, his research includes CAPTCHAs and human computation,[6] which has earned him international recognition and numerous honors. He was awarded a MacArthur Fellowship in 2006,[7][8] the David and Lucile Packard Foundation Fellowship in 2009, a Sloan Fellowship in 2009, and a Microsoft New Faculty Fellowship in 2007, and the Presidential Early Career Award for Scientists and Engineers in 2012.[9] He has also been named one of the 50 Best Brains in Science by Discover, and has made it to many recognition lists that include Popular Science's Brilliant 10,'s 50 Most Influential People in Technology, MIT Technology Review's TR35: Young Innovators Under 35, and Fast Company's 100 Most Innovative People in Business.

Siglo Veintiuno, one of the biggest newspapers in Guatemala, chose him as the person of the year in 2009. In 2011, Foreign Policy Magazine in Spanish named him the most influential intellectual of Latin America and Spain.[10]

Von Ahn's early research[11] was in the field of cryptography. With Nicholas J. Hopper and John Langford, he was the first to provide rigorous definitions of steganography and to prove that private-key steganography is possible.

In 2000, he did early pioneering work with Manuel Blum on CAPTCHAs,[12] computer-generated tests that humans are routinely able to pass but that computers have not yet mastered.[13] These devices are used by web sites to prevent automated programs, or bots, from perpetrating large-scale abuse, such as automatically registering for large numbers of accounts or purchasing huge numbers of tickets for resale by scalpers. CAPTCHAs brought von Ahn his first widespread fame among the general public due to their coverage in the New York Times and USA Today and on the Discovery Channel, NOVA scienceNOW, and other mainstream outlets.

Von Ahn's Ph.D. thesis, completed in 2005, was the first publication to use the term "human computation" that he had coined, referring to methods that combine human brainpower with computers to solve problems that neither could solve alone. Von Ahn's Ph.D. thesis is also the first work on Games With A Purpose, or GWAPs, which are games played by humans that produce useful computation as a side effect. The most famous example is the ESP Game,[14] an online game[15] in which two randomly paired people are simultaneously shown the same picture, with no way to communicate. Each then lists a number of words or phrases that describe the picture within a time limit, and are rewarded with points for a match. This match turns out to be an accurate description of the picture, and can be successfully used in a database for more accurate image search technology. The ESP Game was licensed by Google in the form of the Google Image Labeler, and is used to improve the accuracy of the Google Image Search. Von Ahn's games brought him further coverage in the mainstream media. His thesis won the Best Doctoral Dissertation Award from Carnegie Mellon University's School of Computer Science. In July 2006, von Ahn gave a tech talk at Google on "Human Computation" (i.e., crowdsourcing) which was watched by over one million viewers.[16]

In 2007, von Ahn invented reCAPTCHA, a new form of CAPTCHA that also helps digitize books. In reCAPTCHA, the images of words displayed to the user come directly from old books that are being digitized; they are words that optical character recognition could not identify and are sent to people throughout the web to be identified. ReCAPTCHA is currently in use by over 100,000 web sites and is transcribing over 40 million words per day.[17]

In 2011, he was awarded the A. Nico Habermann development chair in computer science,[18] which is awarded every three years to a junior faculty member of unusual promise in the School of Computer Science.

As of 2014, von Ahn is working on Duolingo, a company that aims to coordinate millions of people to translate the Web into every major language.[19]


Von Ahn has used a number of unusual techniques in his teaching, which have won him multiple teaching awards at Carnegie Mellon University.[20] In the fall of 2008, he began teaching a new course at Carnegie Mellon entitled "Science of the Web". A combination of graph theory and social science, the course covers topics from network and game theory to auction theory.[21]


  1. ^ "Innovators Under 35: 2007". MIT Technology Review. Retrieved 13 August 2015. 
  2. ^ "Luis von Ahn". Carnegie Mellon University. Retrieved 13 August 2015. 
  3. ^ "Teaching computers to read: Google acquires reCAPTCHA". Google Official Blog. 16 September 2009. Retrieved 13 August 2015. 
  4. ^ "Profile: Luis von Ahn",
  5. ^ "Duke Ugrad Alum Profile: Luis von Ahn". Duke University. Retrieved 13 August 2015. 
  6. ^ Robert J. Simmons (2010). "Profile Luis von Ahn: ReCaptcha, games with a purpose". XRDS: Crossroads, The ACM Magazine for Students. 17 (2). doi:10.1145/1869086.1869102. 
  7. ^ "MacArthur Fellows 2006". MacArthur Foundation. Archived from the original on 9 June 2011. Retrieved 13 August 2015. 
  8. ^ "Congratulations, Luis von Ahn". Google Official Blog. 19 September 2006. Retrieved 13 August 2015. 
  9. ^ Office of the Press Secretary (23 July 2012). "President Obama Honors Outstanding Early-Career Scientists". The White House. Retrieved 13 August 2015. 
  10. ^ "Los 10 nuevos rostros del pensiamento iberoamericano". FP (in Spanish). Archived from the original on 29 May 2011. Retrieved 14 August 2015. 
  11. ^ "Luis von Ahn". Google Scholar. Retrieved 14 August 2015. 
  12. ^ Von Ahn, Luis; Blum, Manuel; Hopper, Nicholas J.; Langford, John (May 2003). "CAPTCHA: Using Hard AI Problems for Security". Proceedings of the International Conference on the Theory and Applications of Cryptographic Techniques (EUROCRYPT 2003).
  13. ^ Von Ahn, L.; Blum, M.; Langford, J. (2004). "Telling humans and computers apart automatically". Communications of the ACM. 47 (2): 56–60. doi:10.1145/966389.966390. 
  14. ^ Von Ahn, L.; Dabbish, L. (2004). "Labeling images with a computer game". Proceedings of the 2004 conference on Human factors in computing systems - CHI '04. pp. 319–326. doi:10.1145/985692.985733. ISBN 1581137028. 
  15. ^ Von Ahn, L. (2006). "Games with a Purpose". Computer. 39 (6): 92–94. doi:10.1109/MC.2006.196. 
  16. ^ Google Tech Talk on human computation by Luis von Ahn. (2006-07-26). Retrieved on 2015-06-12.
  17. ^ reCAPTCHA (a.k.a. Those Infernal Squiggly Words) Almost Done Digitizing the New York Times Archive. (2009-11-13). Retrieved on 2012-05-13.
  18. ^ Habermmann Chair announcement. (2011-03-14). Retrieved on 2012-05-13.
  19. ^ Meet Duolingo, Google's Next Acquisition Target; Learn A Language, Help The Web. (2011-04-12). Retrieved on 2012-05-13.
  20. ^ CMU Faculty Awards. Retrieved on 2012-05-13.
  21. ^ 15396 Science of the Web. Retrieved on 2013-11-04.

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