new poker AI bot in the making…
Hurwitz and Tshilidzi Marwala, also at Witwatersrand, have developed a virtual player that has taught itself to bluff at a card game called lerpa. Their artificial intelligence bot, named Aiden, is based on a neural network algorithm that usually forecasts stock market fluctuations.
Crucially, Aiden was not pre-programmed with the rules of lerpa. Instead, Hurwitz and Marwala allowed Aiden to play against three “dumb” virtual players that made choices entirely at random. Aiden was dealt his cards and told which of these could legally be played for each hand. At first he was almost too smart for the task. For the first 40 hands he wouldn’t play, then he tried one hand and lost. This proved so much of a setback that he refused to play again.
Hurwitz then changed tactics, giving Aiden no choice but to play the first 200 hands. Aiden then began to infer the rules of lerpa by treating his cards, his opponents’ actions and his own win-lose history as parameters to learn from. At this stage, though, he still wouldn’t bluff.
Then the researchers decided to play Aiden against three other similarly trained bots to see what would happen. “They began to develop their own personalities – either aggressive or conservative – depending on their past successes,” Hurwitz says. After a streak of being dealt bad hands and consistently folding, one of the more aggressive players, Randy, suddenly changed tactics and began to play even when he had poor cards – he began to bluff. Aiden, a more cautious player, responded by tending to fold even when he held a relatively strong hand (www.arxiv.org/abs/0705.0693).
“Randy suddenly changed tactics and played poor cards. He began to bluff”
“This demonstrates that computers can learn this peculiarly human behaviour,” says Philippe de Wilde, a computer scientist at Heriot-Watt University in Edinburgh, UK. “They generate the strategy from play, which is a very human way of learning.”