Sean Carroll’s Mindscape Podcast

Episode 337 | Kevin Zollman on Game Theory, Signals, and Meaning

Guest: Kevin Zollman (Philosopher, Carnegie Mellon University)
Release date: December 1, 2025

Overview

In this engaging and far-reaching episode of Mindscape, Sean Carroll sits down with philosopher Kevin Zollman to discuss the power and scope of game theory: the mathematical study of strategic interaction. They cover its foundations, its applications across biology and human society, its intersection with meaning and language, and even take a playful detour into parenting—and faculty meetings. Zollman makes the case for game theory as a fundamental tool for understanding not only competition and cooperation but also the emergence of meaning and social conventions.

Key Discussion Points and Insights

1. Defining Game Theory and Its Scope

• What is Game Theory?
  • Kevin Zollman describes it as "the science of strategic thinking. So it's a broad set of mathematical tools that are used for a bunch of different purposes to understand what we call strategic situations." [05:30]
  • Any situation where agents (humans, animals, countries, corporations) interact and their outcomes depend on each other can, in principle, be modeled through game theory.
• Universality & Limitations
  • Game theory is almost always applicable, but it depends on agents’ awareness of options and payoffs. In cases of unawareness (e.g., very simple organisms), classic game theory is less applicable, but evolutionary game theory can pick up the slack. [06:14]

2. History and Foundations of Game Theory

• Von Neumann, Morgenstern, and Poker
  • Story: Game theory’s formal beginnings tie back to John von Neumann, who was keen on beating his friends at poker, and to his collaboration with economist Oscar Morgenstern. [07:20]
• On Utility
  • Utilities formalize preferences. For instance: "I like tea more than coffee. So we would say that my utility for tea is higher than my utility for coffee because I prefer it." [08:26]
  • Measuring and comparing utilities often involves mapping choices and preferences—even under uncertainty.

3. Human Preferences & Behavioral Nuances

• Economics and Psychology Intertwine
  • Observing choices doesn’t always capture true preference: context matters. Example of eating wasabi by mistake vs. on purpose. [11:10]
  • Notable quote:
    "She argues that this idea that economics can completely divorce itself from the way people think about problems is just the wrong way to think about it." [11:53]

4. Classic Games and Insights

• Ultimatum Game
  • Models fairness in splitting resources. Predicts rational acceptance of any offer—but human behavior often deviates for fairness or retaliation. [13:57–16:20]
• Chicken / Hawk-Dove Game
  • Used in both sociology (1950s greaser standoffs) and biology (animal conflict strategies). [20:40]
• Randomization Strategies
  • Some games, like Chicken or Rock-Paper-Scissors, mathematically require unpredictability.
    "Randomization is the best thing. You mentioned in poker. Also true in poker, proven by... von Neumann and Nash." [24:15]

5. Equilibria and Strategy

• Nash Equilibrium & Minimax
  • Simple two-choice games have multiple equilibria, including mixed (probabilistic) strategies. [22:28–24:15]
• Dominant vs. Exploitative Strategies
  • Not every game has a dominant strategy. Most require adapting to opponents’ likely actions.

6. Repeated Games

• From One-Shot to Iterated Interactions
  • Repetition fundamentally changes outcomes. Example: Tit for Tat in the repeated Prisoner's Dilemma encourages cooperation. [31:15]
• Quote:
  "Tit for Tat did really, really well... It's immensely simple, but it seems to do so very well." [35:01]

7. Morality and the Framing of Game Theory

• Game Theory ≠ Advocacy for Selfishness
  • Predictions depend on the utility functions; if agents care about others, cooperation emerges.
    "A lot of things that people describe as prisoner's dilemmas, a game theorist would actually say, no, that's not a prisoner's dilemma…" [36:29]
• Fictional Framing Affects Perceptions
  • The criminal context of Prisoner's Dilemma isn’t always illustrative of the game’s core dynamics. [38:04]

8. Evolutionary Game Theory and Biology

• Standard and Controversial Tool
  • Accepted, but ongoing debates about its explanatory completeness in biology. [39:40]
• Signaling and Sexual Selection
  • Competing theories:
    • Sexy Sons Hypothesis (attraction for its own sake)
    • Signaling Hypothesis (traits signal real qualities)
• Unscrupulous Signaling
  • The "handicap principle": only organisms with genuine traits can afford costly signals. Recent research questions its universality; new models (hybrid equilibria) are being developed, with examples like hummingbirds. [45:00–48:25]

9. Meaning, Intentionality, and Language

• Game Theory and Meaning
  • Signals (like a peacock’s tail) can “mean” something without intentional planning.
  • Quote:
    "If the peacock's tail can mean that peacock is a good mate, then you don't really need to have an intention... a lot of these terms we use in human language... maybe don't have anything to do with intentionality." [56:03]
• Naturalizing Language
  • Philosophers have developed tools to explain meaning, reference, and convention as emergent from game-theoretic coordination (building on David Lewis, Ruth Millikan, Brian Skyrms, Kalin O’Connor, and others). [59:05]
• Implication and Humor
  • Phenomena like implicature ("Can you pass the salt?") can be explained via strategic reasoning. [63:17]

10. Game Theory in Science and Society

• Science as a Game
  • Scientists are strategic actors, too; game theory can help us model incentives, flocking towards new ideas, trust, and dysfunction within scientific communities. [67:49–69:32]
• Misinformation and Tribal Signaling
  • Spread of misinformation can also be analyzed as a form of signaling group membership—even when there's no material benefit.
    "We're constantly signaling group membership to one another. From the way we cut our hair, to the clothes we wear, to the language that we choose to use." [71:55]

11. Game Theory and Parenting

• The Game Theorist’s Guide to Parenting
  • Book co-authored by Zollman offers practical, game-theoretic solutions for common parenting challenges—like dividing cake ("I cut, you pick") and negotiating TV time.
    "Game theory can help you to think about what is the strategic situation that, say, a brother and a sister are having if they're fighting over who gets control of the tv..." [73:35]
• Broader Applications
  • These solutions generalize beyond parenting—think faculty meetings! [76:40]

Notable Quotes and Memorable Moments

• On Game Theory’s Universality
  “I think almost anything could be. […] Game theory is sort of least applicable in [settings where there’s no awareness], but with the exception of cases where people really just don’t even understand that they’re in such a setting, game theory can be applicable.” [06:26]

• On Fairness and Psychology in Games
  “One of the interesting things about the ultimatum game is it provides a nice test bed in order to study how people feel about fairness.” [13:57]

• On Adapting Strategies Over Time
  “Repeated games are incredibly complicated, but also incredibly rich. [...] Tit for Tat is this strategy that says, I'm going to start out by staying silent, and then I'm going to do whatever you did to me on the last round.” [31:15]

• On Language and Meaning
  “Meaning for words is... in its fundamental coordinating aspect. [...] If we can think about meaning as that kind of arbitrary function, then we can start to define meaning in terms of that.” [57:03]

• On Misinformation as Group Signaling
  “Signaling who's our in group and who's our out group is something that humans do quite often—animals do all the time too.” [71:55]

Key Timestamps

| Timestamp | Segment/Topic | |-----------|-------------------------------------------------------| | 00:00 | Opening: The scope of “games” from humans to genes | | 05:05 | What is game theory? | | 07:20 | Game theory’s origins: poker, von Neumann, utilities | | 13:57 | The ultimatum game and fairness | | 20:40 | Chicken/Hawk-Dove: sports, biology | | 22:28 | Nash equilibria, randomness in strategies | | 31:15 | Iterated games, prisoner’s dilemma, Tit for Tat | | 39:40 | Evolutionary game theory in biology | | 44:39 | Signaling: sexual selection & ‘cheater’ problem | | 53:23 | Philosophical discussion: meaning, intentionality | | 59:05 | Origin of conventions and language | | 63:17 | Implicature (“Can you pass the salt?”) | | 67:49 | Science as a game: incentives & flocking | | 71:55 | Misinformation and tribal/group signaling | | 73:35 | Game theoretic parenting | | 76:40 | Faculty meetings, wrap-up |

Listener Takeaways

• Game theory is not just about winner-take-all games or cold calculation. It is a powerful, flexible framework for understanding all kinds of social and biological interactions—including cooperation, fairness, language, and even misinformation.
• Whether you're strategizing at a poker table, raising kids, studying animals, or choosing sides in a faculty meeting, game theory offers surprising and practical insights.
• Much of the beauty and challenge of both human and non-human life can be modeled as strategic play under uncertainty, guided by payoffs, preferences, and evolving rules.

Final words:
"There’s a game theory explanation for everything. At least I think so." — Kevin Zollman [69:47]

[End of summary]