Dealer Omar Abu-Eid adjusts a stack of chips before the first day of the World Series of Poker's main event in Las Vegas last July. Humans still reign in most versions of poker. Whew. John Locher/AP hide caption

itoggle caption John Locher/AP

Ken Jennings, left, and Brad Rutter, right, applauded for Watson earlier in the competition. Carol Kaelson/AP hide caption

itoggle caption Carol Kaelson/AP