Related Experiment Video
Updated: Jul 18, 2026
04:52
Following the Dynamics of Structural Variants in Experimentally Evolved Populations
Published on: February 3, 2023
Evolutionary dynamics of the continuous iterated prisoner's dilemma
1Department of Anthropology, University of California, Haines Hall 341 Box 951553, Los Angeles, CA 90095, USA. Stephen.le@ucla.edu <Stephen.le@ucla.edu>
Journal of Theoretical Biology
|November 28, 2006
Summary
A generous strategy in the continuous iterated prisoner's dilemma (IPD) maximizes payoff but is unstable. Cooperation collapses easily, explaining its rarity in nature.
Area of Science:
- Evolutionary Game Theory
- Behavioral Economics
- Social Sciences
Background:
- The iterated prisoner's dilemma (IPD) models cooperation, with most research on discrete choices (cooperate/defect).
- Continuous IPD allows graded cooperation levels, offering a more nuanced model of social interactions.
Purpose of the Study:
- Analyze a continuous IPD model with a limited strategy set.
- Investigate the stability of cooperative strategies and factors influencing cooperation levels.
Main Methods:
- Mathematical modeling of the continuous iterated prisoner's dilemma.
- Computer simulations using a single-locus infinite alleles Gaussian mutation model.
Main Results:
- A 'generous' strategy maximizes payoff against itself but is vulnerable to invasion by less cooperative strategies.
- Cooperation is prone to rapid decay, with outcomes depending on mutational variance.
- Convex cost functions and high assortment levels hinder cooperation, requiring greater assortment in continuous IPD than discrete IPD.
Conclusions:
- Cooperative equilibria in continuous IPD are inherently unstable, even with significant assortment.
- The model suggests that incremental cooperation can lead to rapid decay, explaining the rarity of cooperation in natural systems.
Related Concept Videos
02:20Dynamic Equilibrium
A reversible chemical reaction represents a chemical process that proceeds in both forward (left to right) and reverse (right to left) directions. When the rates of the forward and reverse reactions are equal, the concentrations of the reactant and product species remain constant over time and the system is at equilibrium. A special double arrow is used to emphasize the reversible nature of the reaction. The relative concentrations of reactants and products in equilibrium systems vary greatly;...
01:24Evolution of New Traits in Microbes
Microorganisms evolve rapidly due to their large population sizes and short generation times, often exhibiting measurable changes within days under laboratory conditions. Natural selection acts on standing genetic variation, enabling the retention and amplification of beneficial traits that confer fitness advantages in changing environments.Adaptive Pigment Regulation in RhodobacterIn Rhodobacter, a genus of purple non-sulfur bacteria, light-harvesting pigments such as bacteriochlorophyll and...
01:07Speciation Rates
Speciation can proceed at markedly different rates, and evolutionary biologists commonly describe these differences through the models of gradualism and punctuated equilibrium. Both patterns explain how new species arise, but they differ in the tempo and continuity of evolutionary change. In both cases, evolutionary change arises from heritable variation within populations, with natural selection often shaping traits that improve survival and reproduction under specific environmental conditions.
01:38Limits to Natural Selection
Organisms that are well-adapted to their environment are more likely to survive and reproduce. However, natural selection does not lead to perfectly adapted organisms. Several factors constrain natural selection.For one, natural selection can only act upon existing genetic variation. Hypothetically, redtusks may enhance elephant survival by deterring ivory-seeking poachers. However, if there are no gene variants—or alleles—for redtusks, natural selection cannot increase the prevalence of...
01:23Criticisms of the Evolutionary Perspective
In a study where individuals posing as strangers offered compliments and proposed casual sex to students, the responses differed significantly based on gender. Not a single woman accepted the proposal, while 70% of the men agreed. This outcome provides a useful scenario to explore through the lens of evolutionary psychology and social learning theory, highlighting the diverse perspectives on human sexual behaviors.
Evolutionary psychology provides one explanation for these findings, suggesting...
Evolutionary psychology provides one explanation for these findings, suggesting...
01:31Alternative Sets of Equilibrium Equations
When analyzing the behavior of structures, engineers often rely on the concept of equilibrium. This refers to the state where all forces and moments acting on a system balance each other, resulting in no net movement or rotation. In many cases, equilibrium can be described by a set of standard equations. However, in some situations, alternative sets of equilibrium equations must be used to describe the system's behavior accurately.
One example of such a situation can be observed in a...
One example of such a situation can be observed in a...