Detecting Betrayal in Diplomacy Games
Interesting research detecting betrayal in the game of Diplomacy by analyzing interplayer messages.
One harbinger was a shift in politeness. Players who were excessively polite in general were more likely to betray, and people who were suddenly more polite were more likely to become victims of betrayal, study coauthor and Cornell graduate student Vlad Niculae reported July 29 at the Annual Meeting of the Association for Computational Linguistics in Beijing. Consider this exchange from one round:
Germany: Can I suggest you move your armies east and then I will support you? Then next year you move [there] and dismantle Turkey. I will deal with England and France, you take out Italy.
Austria: Sounds like a perfect plan! Happy to follow through. And—thank you Bruder!
Austria’s next move was invading German territory. Bam! Betrayal.
An increase planning-related language by the soon-to-be victim also indicated impending betrayal, a signal that emerges a few rounds before the treachery ensues. And correspondence of soon-to-be betrayers had an uptick in positive sentiment in the lead-up to their breach.
Working from these linguistic cues, a computer program could peg future betrayal 57 percent of the time. That might not sound like much, but it was better than the accuracy of the human players, who never saw it coming. And remember that by definition, a betrayer conceals the intention to betray; the breach is unexpected (that whole trust thing). Given that inherent deceit, 57 percent isn’t so bad.
Back when I was in high school, I briefly published a postal Diplomacy zine.