nep-evo New Economics Papers
on Evolutionary Economics
Issue of 2025–09–22
four papers chosen by
Matthew Baker, City University of New York


  1. Belief Diversity and Cooperation By Georgy Lukyanov; David Li
  2. Intergroup cooperation and reputation for honesty in an OLG framework By Georgy Lukyanov; David Li
  3. Ancestral origins of attention to environmental issues By C\'esar Barilla; Palaash Bhargava
  4. Intergenerational Population Ethics By Paolo Giovanni Piacquadio

  1. By: Georgy Lukyanov; David Li
    Abstract: This paper studies a two-player game in which the players face uncertainty regarding the nature of their partner. In this variation of the standard Prisoner's Dilemma, players may encounter an 'honest' type who always cooperates. Mistreating such a player imposes a moral cost on the defector. This situation creates a trade-off, resolved in favor of cooperation if the player's trust level, or belief in their partner's honesty, is sufficiently high. We investigate whether an environment where players have explicit beliefs about each other's honesty is more or less conducive to cooperation, compared to a scenario where players are entirely uncertain about their partner's beliefs. We establish that belief diversity hampers cooperation in environments where the level of trust is relatively low and boosts cooperation in environments with a high level of trust.
    Date: 2025–09
    URL: https://d.repec.org/n?u=RePEc:arx:papers:2509.08851
  2. By: Georgy Lukyanov; David Li
    Abstract: This paper studies an infinite-horizon framework in which two large populations of players are randomly matched to play a Prisoner's Dilemma. Each player lives for two consecutive periods: as a young player from one group, and then as an old player in the other group. Each population has a known fraction of honest types - individuals who always cooperate unless paired with a player who has been observed to defect against a cooperating partner in the past. Because such defections (i.e., breakdowns of trust) are publicly observed, any defector risks carrying a stigma into future interactions. We show that when the benefits from defection are sufficiently large, there exists an equilibrium in which an increase in the fraction of honest types can reduce the likelihood of cooperation. Moreover, we demonstrate that introducing imperfect public memory - allowing past misdeeds to be probabilistically "cleared" - does not enhance cooperation.
    Date: 2025–09
    URL: https://d.repec.org/n?u=RePEc:arx:papers:2509.04748
  3. By: C\'esar Barilla; Palaash Bhargava
    Abstract: How does the climatic experience of previous generations affect today's attention to environmental questions? Using self-reported beliefs and environmental themes in folklore, we show empirically that the realized intensity of deviations from typical climate conditions in ancestral generations influences how much descendants care about the environment. The effect exhibits a U-shape where more stable and more unstable ancestral climates lead to higher attention today, with a dip for intermediate realizations. We propose a theoretical framework where the value of costly attention to environmental conditions depends on the perceived stability of the environment, prior beliefs about which are shaped through cultural transmission by the experience of ethnic ancestors. The U-shape is rationalized by a double purpose of learning about the environment: optimal utilization of typical conditions and protection against extreme events.
    Date: 2025–09
    URL: https://d.repec.org/n?u=RePEc:arx:papers:2509.09598
  4. By: Paolo Giovanni Piacquadio
    Abstract: This paper characterizes a novel class of welfare criteria for settings with endogenous population. The core innovation is to treat parents’ fertility preferences as ethically relevant, deferring to them on the quality--quantity trade-off under conditions of equality. The resulting family of criteria generalizes discounted utilitarianism by reconciling respect for parents' fertility preferences with equity across generations. These criteria resolve long-standing normative dilemmas that afflict existing approaches to population ethics, such as total and average utilitarianism. After formal characterization, I illustrate the criterion in stylized examples and a Barro–Becker environment.
    Keywords: intergenerational justice, fertility preferences, exponentially-discounted utilitarianism, social welfare
    JEL: D60 D70
    Date: 2025
    URL: https://d.repec.org/n?u=RePEc:ces:ceswps:_12106

This nep-evo issue is ©2025 by Matthew Baker. It is provided as is without any express or implied warranty. It may be freely redistributed in whole or in part for any purpose. If distributed in part, please include this notice.
General information on the NEP project can be found at https://nep.repec.org. For comments please write to the director of NEP, Marco Novarese at <director@nep.repec.org>. Put “NEP” in the subject, otherwise your mail may be rejected.
NEP’s infrastructure is sponsored by the School of Economics and Finance of Massey University in New Zealand.