AI surpasses humans at six-player poker

Superhuman performance by artificial intelligence (AI) has been demonstrated in two-player, deterministic, zero-sum, perfect-information games (1) such as chess, checkers (2), Hex, and Go (3). Research using AI has broadened to include games with challenging attributes such as randomness, multiple players, or imperfect information. Randomness is a feature of dice games, and card games include the additional complexity that each player sees some cards that are hidden from others. These aspects more closely resemble real-world situations, and this research may thus lead to algorithms with wider applicability. On page 885 of this issue, Brown and Sandholm (4) show that a new computer player called Pluribus exceeds human performance for six-player Texas hold'em poker.