Ever wondered why certain habits, business models, or social dynamics persist despite seemingly better alternatives? The Evolutionary Stable Strategy (ESS), a powerful mental model borrowed from evolutionary biology, can shed some light on this phenomenon. It helps us understand why some strategies, once established, become incredibly difficult to displace, even if they aren’t perfect.

1. What is Evolutionary Stable Strategy? #

An Evolutionary Stable Strategy is a strategy that, if adopted by a population, cannot be invaded by any alternative strategy. Think of it as a strategy so successful within a specific environment that any mutant strategy trying to gain a foothold would ultimately fail. It’s a form of Nash equilibrium in evolutionary biology, meaning that everyone is doing the best they can, given what everyone else is doing.

This model originated in evolutionary biology, primarily thanks to the work of John Maynard Smith and George R. Price in the 1970s. They were looking to explain the prevalence of certain behaviors in animal populations, particularly those related to competition and cooperation. While developed for biology, the ESS concept has proven remarkably adaptable and relevant across various domains.

2. How It Works #

Imagine a game of Rock, Paper, Scissors played over generations. If everyone played only “Rock,” a mutant “Paper” strategy could invade and dominate. Similarly, if everyone played “Paper,” “Scissors” would take over. An Evolutionary Stable Strategy isn’t necessarily the best strategy in isolation, but it’s resistant to invasion by other strategies when it’s already widespread.

Here’s a breakdown of the key components:

• Population: A group of interacting individuals (e.g., businesses in a market, people in a social group, animals in an ecosystem).
• Strategies: The different ways individuals can behave or operate (e.g., pricing strategies for businesses, social norms in a community, mating rituals in animals).
• Payoff: The benefit or cost associated with each strategy (e.g., profit for a business, social acceptance for an individual, reproductive success for an animal).
• Invasion: The introduction of a new strategy into the population.

Think of a seesaw. On one side, you have the current dominant strategy. On the other side, a new, potentially disruptive strategy. The ESS is like a heavy weight placed on the seesaw, making it extremely difficult for the new strategy to tip the balance and take over, even if the new strategy might offer a slight advantage in isolation. The existing strategy benefits from its established position, network effects, and accumulated advantages.

3. Examples of the Model in Action #

• Business: QWERTY Keyboard Layout. The QWERTY keyboard layout, designed to slow down typing speed to prevent early typewriters from jamming, is far from the most efficient layout. However, its dominance is an Evolutionary Stable Strategy. Millions have learned to type on it, software is built around it, and switching to a more efficient layout like Dvorak would require a massive, coordinated effort, leading to significant short-term disruption with uncertain long-term benefits.

• Personal Life: Social Norms. In many cultures, standing in line is the accepted way to wait your turn. While someone might occasionally try to cut in line, this behavior is usually met with disapproval or even active resistance from the rest of the population. The social norm of queuing is an Evolutionary Stable Strategy because it maintains order and fairness, and any attempt to deviate from it is likely to be punished by the group.

• Science: The Prisoner’s Dilemma. The Prisoner’s Dilemma, a classic game theory scenario, often demonstrates the power of a “tit-for-tat” strategy. Players initially cooperate, but then reciprocate their opponent’s previous move. This strategy can become an Evolutionary Stable Strategy in repeated interactions because it rewards cooperation while punishing defection, discouraging players from continuously trying to exploit each other.

4. Common Misunderstandings or Pitfalls #

• Equating ESS with “Best” or “Optimal”: An ESS isn’t necessarily the most efficient or desirable outcome. It’s simply the strategy that is most resistant to change within the existing environment. The QWERTY keyboard is a prime example.
• Ignoring Environmental Changes: An ESS is only stable as long as the environment remains relatively constant. Changes in technology, consumer preferences, or social norms can disrupt the established equilibrium, allowing new strategies to invade.
• Thinking it’s Static: While ESS describes a relatively stable state, it doesn’t mean things are frozen. There can be minor fluctuations and adaptations within the framework of the ESS.

5. How to Apply It in Daily Life #

Understanding the Evolutionary Stable Strategy can help you:

• Identify entrenched patterns: Recognize the underlying forces that maintain existing behaviors, systems, and structures in your life and the world around you.
• Assess the difficulty of change: Evaluate the challenges of introducing new ideas or approaches, considering the inertia and resistance from existing strategies.
• Strategize for disruption: If you want to disrupt an ESS, understand what factors are keeping it in place and develop strategies to address those factors effectively. This may involve creating incentives, leveraging network effects, or adapting to the existing environment.
• Question assumptions: Don’t blindly accept existing strategies. Consider whether they are truly the best option or simply remnants of historical circumstances.

Ask yourself:

• “What are the dominant strategies in this situation?”
• “Why are these strategies so persistent?”
• “What would it take to shift the balance and introduce a new strategy?”

6. Related Mental Models #

• Network Effects: A phenomenon where a product or service becomes more valuable as more people use it. This can reinforce an existing ESS, making it even harder for new strategies to gain traction.
• Path Dependence: Decisions made in the past can significantly influence future choices, even if those initial decisions were not optimal. This can lock in an ESS, making it difficult to deviate from the established path.
• Game Theory: A framework for analyzing strategic interactions between individuals or groups. Concepts like the Prisoner’s Dilemma and Nash equilibrium are closely related to the Evolutionary Stable Strategy.

By understanding the Evolutionary Stable Strategy, you can gain a deeper appreciation for the dynamics of change and persistence in the world around you and make more informed decisions about how to navigate and shape that world.