An AI Poker Bot Has Whipped the Pros


Humans have been bested by a computer in yet another game once considered too difficult for artificial intelligence to master.

Over the past three weeks, an AI poker bot called Libratus has played thousands of games of heads-up, no-limit Texas hold’em against a cadre of top professional players at Rivers Casino in Pittsburgh. And it beat them all.

Our own Will Knight recently explained why victory for Libratus, which was built by a pair of researchers at Carnegie Mellon University, would be such a big deal:

Poker requires reasoning and intelligence that has proven difficult for machines to imitate. It is fundamentally different from checkers, chess, or Go, because an opponent’s hand remains hidden from view during play. In games of “imperfect information,” it is enormously complicated to figure out the ideal strategy given every possible approach your opponent may be taking.

In heads-up, no-limit Texas hold’em, then, it’s virtually impossible, for there is no single correct play. Instead, the AI must use game theory to calculate optimal plays given the uncertainties.

In the end, it wasn’t even close: Libratus made off with $1.8 million in chips, while all four of the pros ended up with a deficit. Artificial intelligence has never beaten top players at a game so lacking in information as no-limit Texas hold’em. Like DeepMind’s Go victory before it, then, the win is a seminal moment for the machine learning community.

But what was it like for the humans to play against? “It’s slightly demoralizing,” Jason Les, one of the professionals, told the Guardian. “If you play a human and lose, you can stop, take a break. Here we have to show up to take a beating every day for 11 hours a day. It’s a real different emotional experience when you’re not used to losing that often.”

Daniel McAulay, another professional, explained to Wired that the AI’s ability to hold different plays in its memory made it stand apart from human contenders. “It splits its bets into three, four, five different sizes,” he explained. “No human has the ability to…



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