Knowing the answers to the questions is only half the battle. What is really important is pushing the button at the right time, which brings me to my question. Does Watson activate the button mechanically, like his human counterparts?
Yes. As they explained it last night... Watson pursues multiple lines of “reasoning” when working on a question. This generates multiple possibly answers that get refined and possibly re-enforced by further analysis. When Watson’s confidence in a particular answer exceeds a threshold value, it buzzes in. It uses a solenoid to activate a pushbutton switch tied to the regular Jeopardy gear.
My understanding is that Watson mechanically operates a plunger-type of control, just like a human. The difference is that Watson receives a text file at the instant that the other contestants start to hear the question. Watson's comprehension of the question is undoubtedly much faster, so Watson is apt to "buzz in" first.
I knew the answer to all but three of the questions tonight. I suspect that Ken Jennings and the other fellow knew just about every question too. But Watson reacts faster than they can, so Watson controls the board.