An artificial intelligence program developed by IBM this month showed off a speedy ability to understand and answer questions about mystery writer Agatha Christie, the ancient city of Jericho.and film singer Maurice Chevalier. The advanced analysis software, called Watson, beat two former Jeopardy! champions in a practice round that set the stage for nationally televised man vs. machine rematches Feb. 14-16.

The events, which are partly promotional stunts and partly a charity fund-raiser, also show computer science breakthroughs with serious applications. The language and analytical capabilities may support medical diagnosis, finance, legal research customer service and other areas. "What Watson does and has demonstrated is the ability to advance the field of artificial intelligence by miles," says IBM research director John Kelly.

Watson isn't linked to the Internet, but has a massive database covering a broad range of topics. The machine, named after legendary International Business Machines president Thomas Watson, uses refrigerator-size computers too large for the broadcast set. The biggest challenge was getting Watson to differentiate between literal and metaphorical expressions and to understand humor, puns and slang -- areas where the human mind still has an edge.

IBM executive says: "We have created a computer system which has the ability to understand natural human language, which is a very difficult thing for a computer to do." -- John Kelly, director of IBM Research

Game show champ says: "I'm very impressed. . . [But] Watson is fallible." -- Ken Jennings, past winner of 74 straight Jeopardy! games

Author says: "It is going to be more difficult to seriously argue that there are human tasks that computers will never achieve." -- Ray Kurzweil, PC Magazine blogger and author of The Age of Intelligent Machines