Baumard et al. discuss two alternative accounts of the emergence of fairness norms, which they label the “partner-control” and the “partner-choice” model, respectively. The partner-choice model, which they favour, is a market setting where each individual can shop around for the best partner, and her payoff (the return of her labour) is determined by her relative contribution to total output. The partner-control model instead represents a situation where each individual is stuck in a long-term dyadic relation and can only protect herself from exploitation by withdrawing her contribution in case her partner is cheating. Baumard et al. find two faults with partner-control models: (1) They are notoriously underdetermined – there are too many equilibria of long-term cooperation; and (2) in some equilibria the distribution of resources is unfair (payoffs ratios may not reflect contribution ratios).
Notice, however, that, strictly speaking, bargaining theory offers a unifying account of partner-choice and partner-control models under the general principle that negotiated distributions of resources reflect relative bargaining power. Power, in turn, is measured by the difference between individuals' negotiated payoffs and the payoff they would obtain if bargaining broke down (their outside options). The general theory helps one appreciate that effort and talent are only two factors among those that determine an individual's bargaining power. The availability of alternative partners is another factor, but so are physical strength (the capacity to offend or coerce), accumulated wealth, membership in a coalition, and so forth. Baumard et al.'s market for partners effectively abstracts away from such factors and focuses on effort and talent only. This may be a good approximation to the ancestral environment where fairness norms initially evolved, but need not be true of many other ecological and social niches created by homo sapiens since then.
The ethnography of small societies emphasises hunter-gatherers' relative freedom to change partners and their highly egalitarian, anti-hierarchical ethos. This literature strikes a chord in our post-enlightenment democratic culture, but at the same time invites over-generalization from an unrepresentative sample. If we plot the influence of egalitarian mutualism on human social organization throughout history, we obtain a peculiar U-shaped curve (Boehm Reference Boehm1999). Starting approximately from 10,000 BC, egalitarian nomadic societies were progressively displaced by sedentary agriculturalists. Agriculture co-evolved with a new social organization based on caste systems, centralized power, and monopoly of violence – in short, the birth of the state (Dubreuil Reference Dubreuil2010a). This step is not inconsistent with Baumard et al.'s explanatory framework: The new states capitalized on intensive production and food storage. Interestingly, they emerged in highly fertile areas surrounded by arid land, which reduced mobility and the range of outside options. The necessity to defend fertile land and stored food encouraged the creation of a warrior class, which in turn facilitated the maintenance of social order. Demographic growth and low mobility, moreover, created massive coordination problems that were best solved by centralized monarchies.
Could mutualism survive in this new social environment? In hierarchical societies egalitarian mutualism can regulate, at best, horizontal relations among the members of the same caste. Vertical relations, however, must be governed by entirely different norms. Moral theories and political ideologies must justify a stratified system of privileges, rights, and duties that stem from a central authority endowed with absolute power of life and death over its people. Myths and religions typically provide a touch of supernatural legitimacy to these massive asymmetries of bargaining power.
The upshot of all this is not that pursuing an evolutionary explanation of fairness norms is futile. It is, rather, that an exclusive focus on mutualism may lead to an overly narrow account of the evolution of human morality. Clearly humans have evolved the capacity to create and follow fairness norms. But we have little evidence that this capacity is a distinctive module in the sense of evolutionary psychology – a set of mechanisms that calls for a separate, dedicated evolutionary explanation. Humans may have evolved a much more general capacity to normativize behaviour – that is, to create and follow social norms. The content of such norms probably varies across epochs and cultures, and partly co-varies with the underlying socio-economic structure. From a mutualistic perspective, the social and moral systems that different groups of homo sapiens have endorsed at different points in time range from the very fair to the extremely unfair. (Baumard et al. conveniently limit their survey to small groups of hunter-gatherers and to large contemporary societies imbued with democratic ethos. Elevating mutualism to the evolved ethos of homo sapiens, however, ignores ten millennia of very non-mutualistic, un-fair morality and politics.)
Notice that seen in this light the alleged weakness of partner-control models – their underdetermination – may turn out to be a strength: Repeated interactions can give rise to very different social institutions, depending on the underlying asymmetries of bargaining power (Binmore Reference Binmore2005). Such a perspective may be disturbing for those who believe in a core of evolved, stable, universal moral dispositions. On the other hand, it works as a recipe against complacency, and as an invitation to vigilance, for all those who endorse mutualistic fairness while recognizing its historical contingency, cultural relativity, and inherent fragility.
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Baumard et al. discuss two alternative accounts of the emergence of fairness norms, which they label the “partner-control” and the “partner-choice” model, respectively. The partner-choice model, which they favour, is a market setting where each individual can shop around for the best partner, and her payoff (the return of her labour) is determined by her relative contribution to total output. The partner-control model instead represents a situation where each individual is stuck in a long-term dyadic relation and can only protect herself from exploitation by withdrawing her contribution in case her partner is cheating. Baumard et al. find two faults with partner-control models: (1) They are notoriously underdetermined – there are too many equilibria of long-term cooperation; and (2) in some equilibria the distribution of resources is unfair (payoffs ratios may not reflect contribution ratios).
Notice, however, that, strictly speaking, bargaining theory offers a unifying account of partner-choice and partner-control models under the general principle that negotiated distributions of resources reflect relative bargaining power. Power, in turn, is measured by the difference between individuals' negotiated payoffs and the payoff they would obtain if bargaining broke down (their outside options). The general theory helps one appreciate that effort and talent are only two factors among those that determine an individual's bargaining power. The availability of alternative partners is another factor, but so are physical strength (the capacity to offend or coerce), accumulated wealth, membership in a coalition, and so forth. Baumard et al.'s market for partners effectively abstracts away from such factors and focuses on effort and talent only. This may be a good approximation to the ancestral environment where fairness norms initially evolved, but need not be true of many other ecological and social niches created by homo sapiens since then.
The ethnography of small societies emphasises hunter-gatherers' relative freedom to change partners and their highly egalitarian, anti-hierarchical ethos. This literature strikes a chord in our post-enlightenment democratic culture, but at the same time invites over-generalization from an unrepresentative sample. If we plot the influence of egalitarian mutualism on human social organization throughout history, we obtain a peculiar U-shaped curve (Boehm Reference Boehm1999). Starting approximately from 10,000 BC, egalitarian nomadic societies were progressively displaced by sedentary agriculturalists. Agriculture co-evolved with a new social organization based on caste systems, centralized power, and monopoly of violence – in short, the birth of the state (Dubreuil Reference Dubreuil2010a). This step is not inconsistent with Baumard et al.'s explanatory framework: The new states capitalized on intensive production and food storage. Interestingly, they emerged in highly fertile areas surrounded by arid land, which reduced mobility and the range of outside options. The necessity to defend fertile land and stored food encouraged the creation of a warrior class, which in turn facilitated the maintenance of social order. Demographic growth and low mobility, moreover, created massive coordination problems that were best solved by centralized monarchies.
Could mutualism survive in this new social environment? In hierarchical societies egalitarian mutualism can regulate, at best, horizontal relations among the members of the same caste. Vertical relations, however, must be governed by entirely different norms. Moral theories and political ideologies must justify a stratified system of privileges, rights, and duties that stem from a central authority endowed with absolute power of life and death over its people. Myths and religions typically provide a touch of supernatural legitimacy to these massive asymmetries of bargaining power.
The upshot of all this is not that pursuing an evolutionary explanation of fairness norms is futile. It is, rather, that an exclusive focus on mutualism may lead to an overly narrow account of the evolution of human morality. Clearly humans have evolved the capacity to create and follow fairness norms. But we have little evidence that this capacity is a distinctive module in the sense of evolutionary psychology – a set of mechanisms that calls for a separate, dedicated evolutionary explanation. Humans may have evolved a much more general capacity to normativize behaviour – that is, to create and follow social norms. The content of such norms probably varies across epochs and cultures, and partly co-varies with the underlying socio-economic structure. From a mutualistic perspective, the social and moral systems that different groups of homo sapiens have endorsed at different points in time range from the very fair to the extremely unfair. (Baumard et al. conveniently limit their survey to small groups of hunter-gatherers and to large contemporary societies imbued with democratic ethos. Elevating mutualism to the evolved ethos of homo sapiens, however, ignores ten millennia of very non-mutualistic, un-fair morality and politics.)
Notice that seen in this light the alleged weakness of partner-control models – their underdetermination – may turn out to be a strength: Repeated interactions can give rise to very different social institutions, depending on the underlying asymmetries of bargaining power (Binmore Reference Binmore2005). Such a perspective may be disturbing for those who believe in a core of evolved, stable, universal moral dispositions. On the other hand, it works as a recipe against complacency, and as an invitation to vigilance, for all those who endorse mutualistic fairness while recognizing its historical contingency, cultural relativity, and inherent fragility.