This post discusses the expansion of cooperation in the Neolithic, the current geological epoch that began 11,700 years ago in the Near-East. We will explore three hypotheses: that food surpluses, that institutions, and that common threats such as warfare are major drivers of cooperation.
In our analysis of cooperation in the Paleolithic (the Paleolithic is the era that precedes the Neolithic, which began around 11,700 years ago in the Near East and at later times in other parts of the world), we saw how groups of human societies in the Paleolithic cooperated on a large scale. We saw that the nature and extent of large-scale cooperation is debated. Two recent papers in particular—Boyd and Richerson (2022) and Singh and Glowacki (2022)—suggest that cooperation between distinct groups of hunter-gatherers was common, challenging the conventional view that such cooperation was rare and not a significant part of the human evolutionary milieu. In particular, the latter paper proposes the “diverse histories” model, which holds that both large-scale cooperation and group separation, as well as nomadism and semi-sedentarism were both common. It follows that no particular lifeway is “natural”, and humans are prepared for either one.
However, we also saw that the evidence behind these two papers is mixed. While the conventional view does deserve to be challenged, it would be a mistake to conclude the opposite and find too much similarity between Paleolithic societies and the settled farming societies of the Neolithic.
Cooperation and Food Surplus
A leading hypothesis about the expansion of cooperation is that it is tied to food surplus. Vásárhelyi and Scheuring (2018) build a model of how division of labor, a more narrow form of cooperation, may have developed. In their model, individuals have both a personal proficiency and a genetic fitness for a task, both of which improve with performance. In a subsistence society, individuals need to remain generalists, as the ecology punishes gaps in skillsets more than it rewards expertise in a particular area. With a food surplus, the situation reverses and specialization is rewarded more than generalization. The authors suggest that their model may explain the “Sapient Paradox”, as described by Renfrew (2008)—if humans had achieved anatomical and cognitive modernity by about 60,000 years ago, then why did it take until 10,000 years ago for technology to begin advancing rapidly? The explanation of Vásárhelyi and Scheuring (2018) is that the missing ingredient, fulfilled around 10,000 years ago by favorable ecological conditions, was food surplus.
Shavit and Sharon (2023) approach the question of cooperation and the Neolithic revolution from a different angle. A central puzzle of early agricultural societies is that, especially during a bad wet season, it appears rational for individual farmers to revert to hunting and gathering, even though it is best for the group as a whole for them to remain farmers. The authors posit that social pressures, such as from a “shaman”, would have prevented reversion. This is evidence, according to Shavit and Sharon (2023), that cooperation preceded agriculture and was thus a cause, rather than an effect as in the model of Vásárhelyi and Scheuring (2018), of agriculture.
Turchin et al. (2022) also find that surplus has been a major driver of large-scale cooperation. Combining cultural evolution theory, as described by Richerson and Christiansen (2013) and data in Seshat: Global History Databank, the authors find that the adoption of military technologies—particularly iron weapons and cavalry in the first millennium BC in Eurasia—, as well as agricultural productivity, are the best predictors of social complexity. “Social complexity” is defined as a composite of three measures: social scale, including metrics related to population and geographic area; the number of levels of hierarchy; and metrics related to government sophistication.
Robinson and Barker (2017) examine cooperation more broadly, particularly among humans and ants. In both cases, they find that resource sharing is a major driver of inter-group cooperation, again showing how a food surplus may be a driver of large scale cooperation.
As discussed elsewhere, Boyd and Richerson (2022) and Singh and Glowacki (2022) both challenge the notion that surplus is a decisive factor in the emergence of large scale cooperation, noting that such cooperation preceded the surplus that would be generated from agriculture. Popular books such as James Scott’s Against the Grain: A Deep History of the Earliest States (Scott 2017) invert the relationship and argue that the emergence of large, social hierarchies led to surplus which early states coercively extracted from farmers, rather than a surplus allowing the emergence of hierarchies. Nevertheless, while surplus is certainly not the only factor to explain cooperation, the bulk of research suggests that it was, at least, a major factor.
The Role of Institutions
For this article, the definition of an “institution” is taken from Hurwicz (1996), which is that an institution is the set of possible game forms in a society. What this actually means is perhaps better illustrated by examples. Property rights, criminal law, the United States Constitution, the patent system, and money are examples of institutions. These are structures that define how the “players” of the game (e.g. individuals and organizations) are to behave.
A more conventional idea of an “institution” would entail organizations, such as a university, a government, a central bank, or a church. These are not institutions under the definition of Hurwicz (1996). They are players in the game, whereas an institution is the game itself.
Powers, van Schaik, and Lehmann (2016) distinguish economic games and political games. Economic games are played on a regular basis by the individuals and organizations within a system, while political games are played less frequently and govern how the economic games are structured. Elinor Ostrom (see e.g. Ostrom 2009), who won a Nobel Prize in Economics (shared with Oliver Williamson) for her work with institutions and governance of the commons in particular, further considers constitutional games, which determine how political games are played, and meta-constitutional games, which determine how constitutional games are played. The process can only be regressed so far before one reaches immutable laws of human nature.
Powers and Lehmann (2017) discuss several mechanisms that are posited to drive large-scale cooperation, and they argue that each mechanism shows diminishing returns with scale, and thus they are unable to explain cooperation on a very large scale. They conclude that institutions are the one mechanism which can plausibly extend to arbitrarily large scales.
Powers, van Schaik, and Lehmann (2016) explore this hypothesis more thoroughly, regarding institutions as central to the emergence of social complexity. Examples of key institutions were rules for food sharing, rules governing the usage of the irrigation system in an agricultural society; property rights; and later on, rules for sharing reputation among medieval traders. They argue that cooperative breeding—a system by which individuals who are not among the breeding pair help take care of the young—selected for individuals with prosocial orientations and thus helped the capacity of institution formation to appear among Homo sapiens.
Powers, van Schaik, and Lehmann (2016) also assert the importance of language and that nonlinguistic animals are incapable of forming institutions. This position is plausible but not entirely uncontested. Tomasello et al. (2005), for instance, argue that great apes, which are nonlinguistic primates, show behavioral regularities, which in some ways superficially resemble institutions, but are not institutions. Behavioral regularities, such as a flock of birds flying in unison, are widespread in the animal kingdom. According to Tomasello et al. (2005), great apes show awareness of each other’s intentions, but they do not have the shared intentions that are the basis of institutions. Precisely distinguishing between institutions and behavioral regularities is a complex and not settled question.
Casari (2007) provides an account of how institutions can develop, working specifically in the context of property rights and communal governance in the Italian Alps in the late Middle Ages and early modern period. Another valuable paper is Milgrom, North, and Weingast (1990), which discusses by theoretical model the emergence of institutions governing trade in medieval Europe. The challenge for these authors is to explain how norms governing trader behavior may arise when traders are numerous. If one trader cheats another, the two are unlikely to interact again, and so the cheater might not appear to have a strong disincentive to cheat. The model of Milgrom, North, and Weingast (1990) includes the emergence of judges, or law merchants, who spread information about cheating traders. Under the model, a trader pays a fee to a law merchant to gain reputational information about a possible counterparty, and the trader can also pay a fee to file a complaint against a counterparty. The law merchant then levies penalties. The penalty is reputational rather than legal; failure to pay a fine for cheating leaves a trader with a bad reputation and therefore an inability to keep trading. The model is robust against cheating among law merchants. Milgrom, North, and Weingast (1990) present the model as a voluntary system that spontaneously arises among traders and suggests it as a model for how institutions may have developed in the early Neolithic period.
Finally, Powers and Lehmann (2013), who have had quite a lot to say about institutions, discuss how demography and institutions have co-evolved. They build a model in which a patch of resources can support social and asocial populations. Under the model, individuals from social populations can invade asocial populations and create institutions, which thereby enable investment in common goods that raise carrying capacity. Under this model, it would be too simplistic to say that institutions enabled agriculture, or vice versa; the two would have been mutually reinforcing. This adds nuance to the simplistic narrative that institutions caused agriculture in a one-way fashion.
Warfare
There is one more hypothesis to explore here about the emergence of large-scale cooperation in the Holocene: warfare. Stanish and Levine (2011) explore this hypothesis in the context of first millennium BC states around Lake Titicaca in modern-day Peru. The authors find warfare from about 500 BC and a burn site in the first century AD that is most likely the site of major violence. Following the burn, there is evidence of political integration among the states in the region. The authors conclude that warfare is a causal driver of integration.
The aforementioned Robinson and Barker (2017) also discusses common threats as a driver of cooperation. Among many animals, group threats such as predators and harsh environmental conditions are drivers of group formation, and they cite several references on how threats lead to group fusioning, or the merging of several groups into one that can cooperate against the common threat. Warfare would plausibly be such a common threat. Note, however, that group fusioning is different from large-scale cooperation. In the case of cooperation, the groups remain distinct, while under fusioning, the groups become one single group.
Conclusions
The nature and extent of large-scale cooperation in the Paleolithic is unclear, but it is clear that cooperation expanded greatly after the advent of farming. We examined three hypotheses on why this happened. First, we saw that large-scale cooperation, a latent capability of humans, was enabled by the food surplus that favorable climatic conditions of the early Holocene allowed. Second, we saw cooperation was enabled by the uniquely human ability to build institutions, which was further enabled by those same climatic conditions. Third, we saw more briefly that shared threats such as warfare may have been a driver of cooperation.
The evidence in the papers discussed in this post has limitations. Many of the papers build theoretical models, which are sound in their own right, but it is not clear how well the models describe actual societies. Regarding Stanish and Levine (2011), the authors demonstrated warfare and state formation around Lake Titicaca in the late first millennium BC and early first millennium AD, but the causal connection between the two is not clear. Nevertheless, the story we have told today has emerged as a conventional narrative in anthropology of how civilization as we know it emerged from our hunter-gatherer prehistory, though by no means is it universally accepted.
There are further questions. How and why did language develop? Given the connection of language with institutions, this is necessary to understand the human story. There is also a common narrative that the Holocene brought about the favorable climate needed to allow human civilization to develop; previously civilization was a latent capacity. Is this story really accurate? This is a resolution to the Sapient Paradox, but it is not one that is universally accepted.
References
Boyd, R., Richerson, P.J. “Large‐scale cooperation in small‐scale foraging societies”. Evolutionary Anthropology: Issues, News, and Reviews 31(4), pp. 175-198. July 2022.
Casari, M. “Emergence of endogenous legal institutions: Property rights and community governance in the Italian Alps”. Journal of Economic History 67(1), pp. 191-226. 2007.
Hurwicz, L. “Institutions as families of game forms”. The Japanese Economic Review 47(2), pp. 113-132. June 1996.
Milgrom, P.R., North, D.C., Weingast, B.R. “The Role of Institutions in the Revival of Trade: The Law Merchant, Private Judges, and the Champagne Fairs”. Economics & Politics 2(1), pp. 1-23. March 1990.
Ostrom, E. “A General Framework for Analyzing Sustainability of Social-Ecological Systems”. Science 325(5939), pp. 419-422. July 2009.
Powers, S.T., Lehmann, L. “The co-evolution of social institutions, demography, and large-scale human cooperation”. Ecology Letters 16(11), pp. 1356-1364. September 2013.
Powers, S.T., Lehmann, L. “When is bigger better? The effects of group size on the evolution of helping behaviours”. Biological Reviews 92(2), pp. 902-920. May 2017.
Powers, S.T., van Schaik, C.P., Lehmann, L. “How institutions shaped the last major evolutionary transition to large-scale human societies”. Philosophical Transactions of the Royal Society B: Biological Sciences 371(1687): 20150098. February 2016.
Renfrew, C. “Solving the ‘Sapient Paradox’”. BioScience 58(2), pp. 171-172. February 2008.
Richerson, P., Christiansen, M.H. (eds.) Cultural Evolution: Society, Technology, Language, and Religion. MIT Press. November 2013.
Robinson, E.J.H., Barker, J.L. “Inter-group cooperation in humans and other animals”. Biology Letters 13(3): 20160793. March 2017.
Scott, J.C. Against the Grain: A Deep History of the Earliest States. Yale University Press. 2017.
Shavit, A., Sharon, G. “Can models of evolutionary transition clarify the debates over the Neolithic Revolution?”. Philosophical Transactions of the Royal Society B, Biological Sciences 378(1872): 20210413. March 2023.
Singh, M., Glowacki, L. “Human social organization during the Late Pleistocene: Beyond the nomadic-egalitarian model”. Evolution and Human Behavior 43(5), pp. 418-431. September 2022.
Stanish, C., Levine, A. “War and early state formation in the northern Titicaca Basin, Peru”. Proceedings of the National Academy of Sciences 108(34), pp. 13901-13906. August 2011.
Tomasello, M., Carpenter, M., Call, J., Behne, T., Moll, H. “Understanding and sharing intentions: The origins of cultural cognition”. Behavioral and Brain Sciences 28(5), pp. 675-691. October 2005.
Turchin, P., Whitehouse, H., Gavrilets, S., Hoyer, D., François, P., Bennett, J.S., Feeney, K.C., Peregrine, P., Feinman, G., Korotayev, A., Kradin, N., Levine, J., Reddish, J., Cioni, E., Wacziarg, R., Mendel-Gleason, G., Benam, M. “Disentangling the evolutionary drivers of social complexity: A comprehensive test of hypotheses”. Science Advances 8(25): eabn3517. June 2022.
Vásárhelyi, Z., Scheuring, I. “Behavioral Specialization During the Neolithic—An Evolutionary Model”. Frontiers in Sociology 3(35). November 2018.