AI for rock, paper, scissors

A really simple and clever demonstration of another place AI is surprisingly good at beating people: a rock-paper-scissors game on NYTimes. Don't laugh. The computer analyzes your past play and looks for weaknesses to exploit. I played it 100 times and lost 23 to 35, with 42 ties. (I said don't laugh!)

Nifty application. Nice design. The "see what the computer is thinking" is a great way of explaining how the AI works. Much better than saying it's a 4th-order Markov process with backing off.

The small print on the side of the screen is revealing (emphasis mine):

Note: A truly random game of rock-paper-scissors would result in a statistical tie with each player winning, tying and losing one-third of the time. However, people are not truly random and thus can be studied and analyzed. While this computer won't win all rounds, over time it can exploit a person's tendencies and patterns to gain an advantage over its opponent.

This is nice evidence that people are surprisingly bad at being unpredictable.

PS. I ran the numbers. The odds of me doing so poorly against the computer in an even game (one third wins, one third losses, one third ties) are about one in 60, a p value of 0.015. Not impossible, but extremely unlikely. So the smart money is on the computer.