Fairness emerges when partner choice links each interaction to outside opportunities.

Evidence

Using numerical simulations in which individuals can choose with whom they wish to interact, Chiang (2008) has observed the emergence of fairness in an interaction in which partner control alone would have led to the opposite. André and Baumard (2011a) develop a formal understanding of this principle in the simple case of a pairwise interaction. Their demonstration is based on the idea that negotiation over the distribution of benefits in each and every interaction is constrained by the whole range of outside opportunities, determined by the market of potential partners. When social life is made up of a diversity of opportunities in which one can invest time, resources, and energy, one should never consent to enter an interaction in which the marginal benefit of one’s investment is lower than the average benefit one could receive elsewhere. In particular, if all the individuals involved in an interaction are “equal” – not in the sense that they have the same negotiation power within the interaction, but in the more important sense that they have the same opportunities outside the interaction – they should all receive the same marginal benefit from each resource unit that they invest in a joint cooperative venture, irrespective of their local negotiating power. — Nicolas Baumard, A mutualistic approach to morality, 45

Categorization

• QUESTION: The bargaining-power-independent equality via outside opportunity is subtle — worth chasing the André & Baumard formal model to see the precise mechanism.
• XREF: Connects to the reader’s Big God / partner-choice framework on religious solidarity in high-stakes settings — the fumi-e destroys partner choice by removing outside opportunities. — connects to: Fairness evolves from partner choice, not partner control — Nicolas Baumard, A mutualistic approach to morality: The…, 610; Fair prices reflect long-term relationship value rather than local bargaining leverage. — Nicolas Baumard, A mutualistic approach to morality: The…, 630; Partner choice predicts fair cooperation while group selection predicts utilitarian cooperation. — Nicolas Baumard, A mutualistic approach to morality: The…, 637 (+7 more)
• SEED: The claim that marginal benefit always returns to the average outside opportunity is a powerful lens for why coercive institutions (like the fumi-e ritual) matter: they suppress the market that generates fairness.

Related

• Fairness evolved as a psychological device because outside market options constrain benefit distribution. (similarity 0.91)
• Fairness evolves from partner choice, not partner control (similarity 0.90)
• Fairness in cooperation requires outside options, not contribution. (similarity 0.89)
• Fairness equilibria require group-selection processes beyond partner choice alone. (similarity 0.89)
• Fairness evolved to distribute payoffs by input, not equally. (similarity 0.88)
• Fairness is not reducible to mutualistic partner choice. (similarity 0.87)
• Partner choice predicts fair cooperation while group selection predicts utilitarian cooperation. (similarity 0.87)
• Meritocratic fairness norms evolved as adaptations to partner-choice markets (similarity 0.87)
• A disposition to fairness can evolve even when unshared, unlike a disposition to cooperate. (similarity 0.86)
• Partner choice selects among folk-theorem equilibria just as group selection does. (similarity 0.85)
• Morality evolved because fair partners were preferred in cooperative interactions (similarity 0.85)
• A preference for fairness can directly favor equalitarianism in cooperation. (similarity 0.85)
• Fairness distributions reflect bargaining power, not just effort. (similarity 0.84)
• Deriving fairness from bargaining power threatens to reduce moral norms to mere bargaining. (similarity 0.84)
• Morality evolves from individual partner-choice competition, not group selection. (similarity 0.84)

Broader Connections

• Fairness evolved as a psychological device because outside market options constrain benefit distribution. #corroborates (0.95) — Nicolas Baumard, A mutualistic approach to morality, 201
• Meritocratic fairness norms evolved as adaptations to partner-choice markets #corroborates (0.92) — Nicolas Baumard, A mutualistic approach to morality, 324
• Fairness equilibria require group-selection processes beyond partner choice alone. #contradicts (0.88) — Nicolas Baumard, A mutualistic approach to morality, 253
• Cooperation outcomes depend on partner choice frequency, not rule fairness. #qualifies (0.78) — Nicolas Baumard, A mutualistic approach to morality, 257