Human computation and crowdsourcing

I n 1937, Alan Turing formalized the notion of computation by introducing the Turing machine, thus laying the theoretical foundations of modern computer science. Turing also introduced a stronger computational model: a Turing machine with an oracle. In addition to performing computations itself, such a machine is able to ask the oracle questions and immediately receive correct answers, even if these questions are too hard for the machine itself to compute. Depending on the oracle's capabilities, a Turing machine with an oracle therefore could be much stronger than the machine on its own. The oracle itself is an unspecified entity, " apart from saying that it cannot be a machine " (from Turing's 1939 work, Undecidable). The concept of a Turing machine with an oracle is purely mathematical, yet it springs to mind when observing how today's computers use human capabilities in order to solve problems. Computers are now able to complete tasks that involve challenges far beyond what algorithms and artificial intelligence can achieve today— recognizing anomalies in photos, solving a Captcha puzzle, or judging artistic value—by outsourcing these challenges to humans. Millions of people being on the internet is what makes this outsourcing possible on a large scale. It's known as crowdsourcing. Understanding these reversed forms of human-computer symbiosis, in which the computer asks a person to compute something instead of vice versa, is the main object of research in the rising field of human computation. SymbIoSIS While we say that computers are using human capabilities, of course it's really humans who are using computers in order to utilize other humans' capabilities. Indeed, in many applications the role of computers is simply to coordinate between humans as they interact among themselves. This aspect of human computation can be described as a novel form of social organization, in which computers are mediators. The most prominent example is Wikipedia, where computers serve as the platform for aggregation of knowledge and efforts by many people, making it possible to produce a vast, comprehensive, and coherent encyclopedia equivalent to a printed book of around 1,000 volumes, all in a completely distributed manner! The articles in this issue of XRDS provide striking answers to major questions in the field of human computation and crowdsourcing. At the same time, they generate even more questions, highlighting future research directions and opportunities to get involved in the field. IncentIveS Do people partake in human computation tasks …