Play Smarter with Game Theory
Level 5: The Hawk and the Dove - How Nature Plays Games Without Thinking
So far, we’ve looked at game theory in scenarios where players make conscious choices. In classical game theory, rational human players decide whether to cooperate, betray, or mix up their strategies based on the payoff. But in nature, animals don’t sit around drawing payoff matrices. Their “strategies” take the form of instincts, habits, or genes. The ones that provide an advantage in survival and reproduction are the ones that spread over generations.
Imagine a population of animals competing for food. Some play aggressively and we’ll call them hawks. Others avoid conflict and back down, we’ll call them doves. If two hawks meet, they fight. One wins and gets all the food, the other is injured. If a hawk meets a dove, the hawk always wins without a fight. If two doves meet, they share without fighting.
The classic Hawk–Dove game is modeled with a resource value (V) and a cost of injury (C).
When two hawks meet, one wins the resource and the other loses. Each has a 50% chance of winning or losing, so the expected payoff is (V−C)/2.
When a hawk meets a dove, the hawk takes the entire resource, while the dove gets nothing.
When two doves meet, they avoid conflict and share peacefully, each receiving V/2.
Here’s the payoff matrix:
In classical game theory, we look for Nash equilibria. In evolutionary game theory, we look for an evolutionarily stable strategy (ESS). Once this strategy becomes common in a population, it can’t easily be invaded by another. A population of only hawks isn’t stable as too much fighting means too many injuries. A population of only doves isn’t stable either since hawks could invade and exploit them. What tends to be stable is a mix of hawks and doves, balanced so neither strategy takes over completely. This balance emerges naturally, without conscious choice, because strategies that “work” spread, while those that don’t fade away.
Evolutionary game theory helps explain behaviors that at first seem irrational. Take squirrels, for example. Sometimes one will make a loud alarm call when a predator approaches. At first glance, that seems like a bad strategy since the caller draws attention to itself. But the call also helps nearby relatives hide and survive. Since relatives share genes, the strategy can spread through generations. What looks like “altruism” is, at the population level, a stable survival strategy. We can see the same principles in humans. Norms like punishing cheaters or rewarding cooperation may come with short-term costs for the individual; yet, over time, they help groups that follow them outcompete groups that don’t. In this sense, cooperation is strategic.
Evolutionary game theory shows that not all strategies are the result of rational decision-making. In nature, successful behaviors survive and unsuccessful ones disappear. Hawks and doves aren’t choosing consciously; rather, evolution is playing the game for them.
Next time we’ll look back on ourselves and explore the hidden games you play every day without realizing it.
