Strogatz and Toupo modified the rock-paper-scissors equations to allow some “mutant” offspring to play different strategies than their parents. Previous researchers had also studied mutations, but they had assumed that the changes were symmetric—that is, that each strategy mutated to the others at the hand game Rock-paper-scissors is a classic way to settle playground disputes. It turns out nature plays its own version of the game.
Strogatz co-authored a paper on the topic with graduate student Danielle Toupo, published in Physical Review E and featured in the news section of the journal Science. It's on a mathematical model that explains that when players change their strategies on the fly, a stable pattern emerges.
This model could shed light on how living creatures maintain competing strategies in the struggle for existence. Lizards, for example, use three competing strategies – aggression, cooperation and deception – to win mates, with each tactic beating one and losing to another, just like in Rock-paper-scissors.