Alex Trebek explores the depths of Watson's server racks during the IBM Challenge episode of Jeopardy.

Watson, the IBM computer designed to take on humans in the quiz game Jeopardy, made its television debut Monday night. Positioned between two past Jeopardy champs, Ken Jennings and Brad Rutter, Watson’s swirling-globe avatar was able to hold its own, finishing the first round tied with Rutter at $5,000.

Chris Welty, a member of Watson’s algorithms team, was on hand to provide commentary during Rensselaer Polytechnic Institute’s showing of the Jeopardy episode at the school’s Experimental Media and Performing Arts Center. Ars Technica was there to hear his take.

First, a quick rundown of how Watson plays Jeopardy. The computer is fed the answer in text form at the same time the answer panel appears to the two human players. Watson then queries its database for an appropriate question response, a process that doesn’t involve using the internet at all. Welty noted that game shows are federally regulated and there were two auditors present while the episode was filmed to make sure the computer wasn’t querying the internet for info to frame its question responses.

Watson then must push a physical buzzer to respond, just like its human competitors. While this would seem to be a task at which computers would have an overwhelming advantage, Welty noted that Rutter was so well-known for his lightning-fast buzzing that the producers weren’t even mildly concerned.

When the match began, the computer got off to a strong start: It took control of the board away from Rutter on the second turn, immediately nailed a Daily Double square, bet $1,000, and got the question right. But later, on a “Name That Decade” answer, Jennings responded incorrectly with “what is the 1920s?” Watson, which can’t see or hear and so can’t pick up on the follies of its competitors, followed Jennings’ response with its own: “What is the 1920s?”

“No, Ken said that,” Alex Trebek replied as the avatar’s sphere turned orange with embarrassment.

During a commercial after Watson’s decade gaffe, Welty noted that the team thought the ability to process other players’ wrong responses would be unnecessary. “We just didn’t think it would ever happen,” Welty said, laughing.

Watson also tripped up on an “Olympic Oddities” answer, but so imperceptibly that Alex Trebek didn’t notice at first, raising an important point of clarification. After Jennings responded incorrectly that Olympian gymnast George Eyser was “missing a hand,” Watson responded, “What is a leg?”

Welty said Trebek initially accepted Watson’s response, but the taping had to be stopped and the sequence reshot because Trebek had forgotten that Watson wasn’t aware of the context created by Jenning’s response.

If a person had responded to the Oddities question the way Watson did, he or she could have been presumed to be following the context of Jennings’ response, with the “missing”-ness of the leg implied. But since Watson couldn’t have heard Jennings, its response of “What is a leg?” rather than “What is ‘missing a leg’?” was actually deemed incorrect. In the aired version of the episode, Trebek declares Watson’s response wrong.

Last night’s airing was the first of three, and it covered only the first round of the first game. Watson, Jennings, Rutter and Trebek will continue tonight, beginning with the double and final Jeopardy rounds of the first game, with a second full game to be played on the third night.

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