Five Rules for the Evolution of Cooperation

Cooperation is required for new levels of organization like genomes, cells, multicellular organisms, social insects, and human society to emerge. But if cooperation means that individual entities pay some cost c to provide benefit b (both measured in terms of fitness) to some other entity, why should it ever occur in the competitive regime of evolution by natural selection?

Nowak (2006) describes five mechanisms by which natural selection can foster cooperation.

  1. Kin selection. Natural selection can favor cooperation between related individuals, where relatedness r is defined as the probability of sharing a gene. For siblings, r = 1/2; for cousins, r = 1/8, etc. Hamilton’s rule says that cooperation emerges only if r > c/b.
  2. Direct reciprocity. Tit for tat, or I help you if you help me. This requires repeated interactions. More specifically, direct reciprocity can only lead to cooperation if the probability w of another meeting between the same two individuals is greater than the cost-benefit ratio: w > c/b.
  3. Indirect reciprocity. I help you. Somebody helps me.” Indirect reciprocity works via reputation, as your decision to cooperate or defect is observed by others who may gossip about it so that others can use it to decide whether to cooperate with you. It can only support cooperation if the probability q of knowing someone’s reputation is greater than the cost-benefit ratio: q > c/b.
  4. Network reciprocity. Suppose cooperators pay a cost c to benefit each of their neighbors by b. Cooperators can then win out by forming clusters in which they cooperate. The benefit-cost ratio must be greater than the average number of neighbors: b/c > k.
  5. Group selection. Suppose a population is divided into groups, and that cooperators help others in their own group. Individuals reproduce in proportion to their payoff, and offspring are added to the same group. If a group becomes sufficiently large, it can split into two. When this happens, another group goes extinct, so that the total population size is constrained. In the case of weak selection and rare group splitting, we get the following. If n is the maximum group size and m is the number of groups, cooperation can emerge if b/c > 1 + n/m.

These are not all potential mechanisms for the evolution of cooperation. For example, in green beard” models recognize one another via arbitrary markers. Cooperation can also emerge if the game is voluntary: if players can choose cooperate, defect, or walk away, cooperation typically wins out. Punishment can promote cooperation in certain situations, but is not itself a mechanism for the evolution of cooperation. All models of punishment rely on other underlying mechanisms (e.g. indirect reciprocity, group selection, or network reciprocity), but it can increase the rate of cooperation in such models.

May 4, 2023

A Culture of Growth

Related: Economics, cultural evolution, Historical persistence, [Industrial Revolution], [Scientific Revolution]

A 2016 book by Joel Mokyr arguing that a cultural shift in Europe during the early modern period was in part responsible for the Industrial Revolution. In particular, the belief that it was both possible and desirable to manipulate the natural world took hold and made its mark on the world.

He argues that so-called cultural entrepreneurs” played an important role in facilitating this shift. Successful cultural entrepreneurs manage to overthrow existing authorities in a specific area of culture and create a competing variant. While cultural entrepreneurship involves innovation, it is in significant part also about coordination. Cultural entrepreneurs must become sufficiently influential to persuade others to adopt the cultural variant that they are proposing, and attract enough converts so as to have an actual impact on institutions and behaviour. Typically, cultural entrepreneurs will latch on to existing ideas and trends, nudging them in some particular direction. Those who promote ideas that are utterly alien to the audience are unlikely to be successful.

Mokyr argues that both Francis Bacon and Isaac Newton were important cultural entrepreneurs in facilitating this shift. Bacon’s main achievement was to synthesize the work of earlier thinkers into a coherent intellectual framework. In particular, he reinforced the already existing trend of merging the domain of natural science and the domain of the artisan and craftsman. Bacon turned out to be immensely influential. When the Royal Society was founded in 1660, its stated purpose was to increase useful knowledge, and to bridge the gap between formal science and practical applications of the useful arts. Those who followed Bacon believed in the institutionalization of science,  the gathering and dissemination of knowledge through planned and cooperative research. Crucially, they also believed in the possibility of technological solutions to social problems. That is, Bacon’s influence lead to the cultural acceptance of the growth of useful knowledge as a critical ingredient in economic growth.

During Bacon’s time, Europe had been changing dramatically. Voyages to the New World and to Asia had created a world that was more mobile, monetized, and market-oriented. With the discovery of new lands, commitment to the old and resistance to novelties were weakened. Within Europe, urbanization, growing trade, the commercialization of agriculture, as well as the invention of the printing press all helped create a radically new environment in short order. But these events did not make the cultural innovations of early modern Europe inevitable. Other societies responded to such shocks by taking a conservative turn, as was the case in Qing China and Tokugawa Japan. So why was it that Europe, which for centuries had lagged behind both scientifically and technologically, came up with new instruments, built better ships, and invented calculus?

One important factor is that unlike other parts of the world, which were typically dominated by a large empire, Europe was highly fragmented, consisting of several different states that were constantly competing with one another. (cf. Escape from Rome). This meant that European rulers were competing with one another for the most skilled citizens, be they painters, artisans, musicians, or engineers. Such competition between states also made it more difficult for those defending conservatism to coordinate their attempts to suppress intellectual innovators. Those who were persecuted in one state could often set up shop in another one instead. Indeed, it was quite common for members of the creative classes”––craftsmen, engineers, physicians, architects, etc.––to move across the continent. However, what made Europe truly unique was the combination of political fragmentation with intellectual and cultural unity––an integrated market for ideas. This unity came from Europe’s classical heritage, the use of Latin as the lingua franca of intellectuals, and the Christian Church. This intellectual and cultural unity made possible The Republic of Letters, a transnational community of scholars who disseminated ideas and corresponded with one another. This community gave intellectual innovators a much larger audience than they could otherwise have had. It also provided a set of institutional incentives encouraging academic superstars, and also allowing heterodox scholars to spread their original ideas, in the hope of acquiring the respect of their peers.

Cooperative behaviour was encouraged, and defectors could be recognized and punished. This equilibrium is more likely to emerge if the game” is played over and over again, if the participants share an ethos” of cooperation and know that others do, and if the numbers remained small enough that opportunistic behavior can be detected and punished. These conditions obtained in the Republic of Letters far more than anywhere else. The norms it set implied that one was expected to reply to letters, to disclose findings and data truthfully, and to acknowledge intellectual debts. While not always living up to its egalitarian ethos, hierarchy in the Republic of Letters was strikingly different from that of the rest of society in that neither ancestry nor wealth were supposed to count for much. Instead merit, originality, achievement and erudition determined one’s place in the hierarchy.

Over time, science became progressively less secretive, turning useful knowledge into an open-source system,” thereby reducing access costs. This growth in open science did not happen by conscious design, but was rather the byproduct of scholars trying to build reputation among peers in order to gain various advantages, such as financial security, freedom, and time to do undisturbed research through patronage positions. While superstars like Bacon, Spinoza and Newton were of course important, we should not underestimate the impact of less prominent intellectuals, who transmitted and tweaked the products of the great minds, spreading this knowledge and making it easier and faster to access.

What mattered in the long run was the willingness and ability to harness nature to human material needs. The findings of natural philosophy confirmed the beliefs of a mechanistic, understandable universe and a controllable environment that could and should be manipulated for the material benefit of humankind.

Significance, Persistence, Contingency As with the previous case studies I’ve discussed, both the significance and the persistence of this culture of growth should be obvious, at least when assessed with the benefit of hindsight. While the events discussed here are relatively recent compared to the other case studies, we have every reason to expect that they will continue to influence the future, barring some major civilizational collapse.

When it comes to contingency, Mokyr himself provides some clues. He argues that if Europe had had political fragmentation without cultural unity, no cultural entrepreneur would have been able to cover the fixed cost catering to an audience of a few thousand local people. Nor would there have been networks of people from whom scientists could learn. Even a well-integrated and large market for ideas in which there is little competition and limited entry will eventually not be able to generate enough innovation and change, because incumbents would find ways to suppress challenges to their cultural positions. Moreover, he thinks the logic of cultural evolution suggests that contingency and chance played an important role in bringing about this outcome precisely because there was a highly competitive marketplace for ideas and because much of the innovation led to knowledge that was rather untight.  In 1600 it would have been hard to foresee what this competitive market for ideas would lead to.

Mokyr notes that if certain historical events had turned out differently, there may have been no Enlightenment, or perhaps a dramatically different one. For example, this could have happened if Spain had won over the Dutch and the English, or if the Jesuits and other Catholic conservatives had been able to monopolize education and intellectual discourse. And if the intellectual status quo had succeeded in rejecting the novel ideas of the Enlightenment, the Industrial Revolution would probably have fizzled out.

Mokyr acknowledges that very few of the discoveries of the 17th century Scientific Revolution had any direct and major impact on the essential technological advances of the 18th century Industrial Revolution. However, he claims that the important thing about the culture of useful knowledge was not that it gave way to immediate economic benefits, but that most practitioners believed that in the very long run it would. Furthermore, he contends that if technological progress had been entirely carried out by skilled and imaginative artisans, without any input from Baconian-minded intellectuals and scientists, there might have been local technical advances in textiles and metals in the 18th century, but it would not have produced a sustainable and self-reinforcing Industrial Revolution. Many societies characterised by technological stasis were full of highly skilled artisans, especially in Southern and Eastern Asia.

All of this suggests that the culture of growth was fairly contingent. At the same time, if we take the lessons from the previous case study on the Western Church’s family policies to heart, it may well be that the background conditions were unusually well-suited for something like a culture of growth to emerge.

## What does all of this mean for us?

  • How does Mokyr’s notion of cultural entrepreneur relate to the notion of a moral entrepreneur?

December 22, 2021

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December 22, 2021