Rock, Paper, Scissors, and Evolutionary Game Theory in Nature
I’ve always been fascinated with the extent that the game rock, paper, scissors (RPS) has been studied. It’s such a simple game, yet people have discovered countless things about the game, from how to actually gain an advantage psychologically, to using it as a model for real life scenarios.
Specifically, today I stumbled upon an application of RPS in nature, with the side-blotched lizard. There are 3 different types of lizards, each essentially playing a game of RPS in order to earn the right to mate with other lizards. The first type is an aggressive lizard, which attempts to control a large area and mate with any females in this area. The second type is a sneaky lizard, which “beats” the aggressive lizard by mimicking the behavior of females in order to mate undetected in an aggressive lizard’s area. The third type is a lizard that guards one female specifically for mating, which prevents the sneaky lizard from mating. However, this third type isn’t strong enough to overcome the aggressive type.
What might possibly be even more interesting than this RPS scenario playing itself out in nature, is that researchers are able to mathematically model this using evolutionary game theory. Researchers are able to predict, with pretty high accuracy, fluctuations in the population of each type of lizard. Each type of lizard spends some amount of time dominating the population, until the strategy that beats it begins getting reintroduced. For instance, from an intuitive standpoint, we can see that each type of lizard is evolutionarily stable with respect to one other lizard, but not evolutionarily stable with another lizard; thus, none of the lizards have a stable grasp on their whole environment and cannot continue to dominate. Seeing these situations play out in nature shows just how powerful a knowledge of game theory really can be.
http://news.sciencemag.org/biology/2015/05/rock-paper-scissors-may-explain-evolutionary-games-nature