Pluribus, a poker-playing algorithm, can beat the world's top human players, proving that machines, too, can master our mind games.

In his 14 years on the professional poker circuit, Darren Elias had never faced anyone who played with so little fear.

A typical poker player, when dealt two Jacks — one faceup, the other hidden, a hand neither good nor bad — would proceed with caution. But not Elias' opponent, who seemed to know exactly what to do. Even when Elias decided to bluff, betting as if he held a strong hand, his opponent effectively called him on it: charging