FORTUNE -- The scientific test to gauge if a computer can "think" is surprisingly simple: Can it engage in small talk? The so-called Turing test says a computer capable of carrying on a natural conversation without giving itself away can be considered intelligent. So far, no machine has made the cut.
Eric Brown, a research scientist with IBM (ibm), is charged with changing that. The 45-year-old is the brains behind Watson, the supercomputer that pummeled human opponents on Jeopardy! in 2011. The biggest difficulty for Brown, as tutor to a machine, hasn't been making Watson know more but making it understand subtlety, especially slang. "As humans, we don't realize just how ambiguous our communication is," he says.
Case in point: Two years ago, Brown attempted to teach Watson the Urban Dictionary. The popular website contains definitions for terms ranging from Internet abbreviations like OMG, short for "Oh, my God," to slang such as "hot mess."
But Watson couldn't distinguish between polite language and profanity -- which the Urban Dictionary is full of. Watson picked up some bad habits from reading Wikipedia as well. In tests it even used the word "bullshit" in an answer to a researcher's query.
Ultimately, Brown's 35-person team developed a filter to keep Watson from swearing and scraped the Urban Dictionary from its memory. But the trial proves just how thorny it will be to get artificial intelligence to communicate naturally. Brown is now training Watson as a diagnostic tool for hospitals. No knowledge of OMG required.
This story is from the January 14, 2013 issue of Fortune.
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