Watson is an artificial intelligence computer system capable of answering questions posed in natural language, developed in IBM's DeepQA project by a research team led by principal investigator David Ferrucci. Watson was named after IBM's first president, Thomas J. Watson.
In 2011, as a test of its abilities, Watson competed on the quiz show Jeopardy!, in the show's only human-versus-machine match-up to date. In a two-game, combined-point match, broadcast in three Jeopardy! episodes February 14–16, Watson beat Brad Rutter, the biggest all-time money winner on Jeopardy!, andKen Jennings, the record holder for the longest championship streak (74 wins). Watson received the first prize of $1 million, while Ken Jennings and Brad Rutter received $300,000 and $200,000, respectively. Jennings and Rutter pledged to donate half their winnings to charity, while IBM divided Watson's winnings between two charities.
Watson had access to 200 million pages of structured and unstructured content consuming four terabytes of disk storage, including the full text ofWikipedia, but was not connected to the Internet during the game. For each clue, Watson's three most probable responses were displayed on the television screen. Watson consistently outperformed its human opponents on the game's signaling device, but had trouble responding to a few categories, notably those having short clues containing only a few words.
When playing Jeopardy! all players must wait until host Alex Trebek reads each clue in its entirety, after which a light is lit as a "ready" signal; the first to activate their buzzerbutton wins the chance to respond. Watson received the clues as electronic texts at the same moment they were made visible to the human players. It would then parse the clues into different keywords and sentence fragments in order to find statistically related phrases. Watson's main innovation was not in the creation of a new algorithm for this operation but rather its ability to quickly execute thousands of proven language analysis algorithms simultaneously to find the correct answer. The more algorithms that find the same answer independently the more likely Watson is to be correct. Once Watson has a small number of potential solutions it is able to check against its database to ascertain whether the solution makes sense. In a sequence of 20 mock games human participants were able to use the average six to seven seconds that Watson needed to hear the clue and decide whether to signal for responding. During that time Watson also has to evaluate the response and determine whether it is sufficiently confident in the result to signal. Part of the system used to win the Jeopardy! contest was the electronic circuitry that receives the "ready" signal and then examined whether Watson's confidence level was great enough to activate the buzzer. Given the speed of this circuitry compared to the speed of human reaction times, Watson's reaction time was faster than the human contestants except when the human anticipated (instead of reacted to) the ready signal. After signaling, Watson speaks with an electronic voice and gives the responses in Jeopardy!'s question format. Watson's voice was synthesized from recordings that actor Jeff Woodman made for an IBM text-to-speech program in 2004.