Biological signals as handicaps
Abstract
An ESS model of Zahavi's handicap principle is constructed. This allows a formal exposition of how the handicap principle works, and shows that its essential elements are strategic. The handicap model is about signalling, and it is proved under fairly general conditions that if the handicap principle's conditions are met, then an evolutionarily stable signalling equilibrium exists in a biological signalling system, and that any signalling equilibrium satisfies the conditions of the handicap principle. Zahavi's major claims for the handicap principle are thus vindicated. The place of cheating is discussed in view of the honesty that follows from the handicap principle. Parallel signalling models in economics are discussed. Interpretations of the handicap principle are compared. The models are not fully explicit about how females use information about male quality, and, less seriously, have no genetics. A companion paper remedies both defects in a model of the handicap principle at work in sexual selection.
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The equilibrium of a signaling game of incomplete information with rational agents is the same as the mindless evolutionary stable equilibrium resulting from random mutation with replication according to fitness.
“One is the equilibrium of a signaling game of incomplete information with rational agents. The other is the mindless evolutionary stable equilibrium that results from random mutation, with a replication process that increases representation in the population according to fi tness. Grafen (1990) showed that both equilibria are the same.”
From Talking the talk, not walking the walk: The coevolution of overconfidence and loss aversion (2026) · cites this paper as Grafen (1990)
Costly signaling theory proposes that humans engage in costly behaviors to broadcast surplus genetic fitness and abundance of resources.
“Costly signaling theory (Grafen, 1990;Zahavi, 1977) proposes from an evolutionary psychology perspective that humans engage in costly behaviors, that is, behaviors that are not immediately necessary for the survival of the individual, to broadcast to others that they have surplus genetic fitness and abundance of resources.”
From Sustainable clothing: Why conspicuous consumption and greenwashing matter (2023) · cites this paper as Grafen, 1990
The Sir Philip Sidney game was developed by Maynard Smith as a way to model signalling within animal behaviour, and the aim of the model was to illustrate the mechanisms of honest signalling initially proposed by Zahavi and subsequently developed by others.
“The Sir Philip Sidney game was developed by Maynard Smith as a way to model signalling within animal behaviour [12] -in particular, the aim of the model was to illustrate the mechanisms of honest signalling initially proposed by Zahavi [3,9] and subsequently developed by others [10,47].”
From Maynard Smith revisited: A multi-agent reinforcement learning approach to the coevolution of signalling behaviour (2025) · cites this paper as [10]
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- Authors
- Grafen, A.
- Affiliations
- University of Oxford (GB)
- Corresponding author
- Grafen, Alan
- ORCID
- Grafen, Alan
- Venue
- Journal of Theoretical Biology
- Publisher
- Elsevier BV
- Published
- 1990-06
- Volume
- 144
- Issue
- 4
- Pages
- 517-546
- ISSN
- 0022-5193 (ISSN-L)
- OpenAlex
- W2039010464
- Cited by
- 2,462
- References
- 1
- Citations by year
- 2026: 30 · 2025: 54 · 2024: 56 · 2023: 56 · 2022: 75 · 2021: 96 · 2020: 75 · 2019: 74 · 2018: 78 · 2017: 78 · 2016: 91 · 2015: 86 · 2014: 103 · 2013: 97 · 2012: 97
- FWCI
- 142.66
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Journal of Theoretical Biology (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Social Sciences › Sociology and Political Science › Evolutionary Game Theory and Cooperation
- Social Sciences › Psychology › Experimental and Cognitive Psychology › Evolutionary Psychology and Human Behavior
- Life Sciences › Agricultural and Biological Sciences › Ecology, Evolution, Behavior and Systematics › Animal Behavior and Reproduction
- Keywords
- costly signaling, Zahavi, evolutionarily stable strategy, sexual selection
- MeSH terms
- Animals, Animal Communication, Economics, Female, Game Theory, Male, Models, Genetic, Sexual Behavior, Animal
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