Speaking to a room filled with Internet developers at the O'Reilly Emerging Technology Conference in San Diego this week, Luis Felipe Cabrera, Amazon's vice president of software development, outlined a project to harness human intelligence for tasks that computers can't handle well, such as recognizing objects in images.

The backbone of the plan is a Web-services platform called Mechanical Turk. It uses an auction-style system to farm out complex tasks -- complex for a computer, that is -- such as recognizing the difference between a human face and a nearby bush, or accurately transcribing an audio recording. Cabrera likes to call the platform "artificial artificial intelligence" -- it's computers asking humans to do tasks, rather than the other way around.

To illustrate the idea, Cabrera cited a test in which A9.com, Amazon's search engine, asked average users to fulfill "human intelligence tasks" (HITs) -- jobs that computers are notoriously bad at doing, such as picking out one building or business within a photograph of a city block in order to highlight that part of the image in association with a business address.

Not only did participants supply the necessary answers, but they did so "outstandingly fast," according to Cabrera, allowing Amazon to use the photographs in its search results. "This is the tip of the iceberg, but you can see how it enables 'massively parallel' human computing," he said.

Of course, there's a keen irony in all this. At a conference-cum-show dedicated to technology-based solutions, Amazon's Mechanical Turk is an allusion to the famous exhibit in the 1760s, by Hungarian showman Wolfgang von Kempelen, in which a chess-playing automaton, known as The Mechanical Turk, was dressed like a Turkish pasha. It wowed royal audiences -- and even won a few notable chess battles. And it was a complete fake. Von Kempelen, a century before P.T. Barnum, had simply hidden an undersized chess master within the machine, along with pulleys, gears, and other faux-mechanical props.

While Amazon's use of the name might suggest a betrayal of the concept of artificial intelligence (AI), it's actually the latest in string of experiments dealing with the complementary nature of machine and human intelligence.

Two of the best-known AI applications are Google's PageRank algorithm, which counts each human-initiated inbound link to a site as a "vote" for that site's content quality, and Amazon's recommendation system, which uses algorithms to seek out patterns in customer purchase data to market books and other products to customers whose purchase decisions fit the same pattern.

A more recent example is exemplified by sites like Flickr and del.icio.us, which use human-supplied keywords, or tags, to summarize complex information, such as the thematic content of a photographic image or the functional purpose of a website.

But, unlike this methodology, which depends on users generating information without any compensation, Amazon's Mechanical Turk will pony up cash to anyone willing to complete the tasks they want to farm out. Most of the tasks ask people to do little more than, say, match the address and owner in a real-estate title listing or indicate that a photograph is a man or woman -- and they earn mere pennies for each one.