Group beneficial norms are common in human societies. The persistence of such norms is consistent with evolutionary game theory, but existing models do not provide a plausible explanation for why they are common. We show that when a model of imitation used to derive replicator dynamics in isolated populations is generalized to allow for population structure, group beneficial norms can spread rapidly under plausible conditions. We also show that this mechanism allows recombination of different group beneficial norms arising in..
It is often argued that culture is adaptive because it allows people to acquire useful information without costly learning. In a recent paper Rogers analyzed a simple mathematical model that showed that this argument is wrong. Here we show that Rogers ' result is robust. As long as the only benefit of social learning is that imitators avoid learning costs, social learning does not increase average fitness. However, we also show that social learning can be adaptive if it makes individual (...) learning more accurate or less costly. (shrink)
The complexity of human societies of the past few thousand years rivals that of social insect societies. We hypothesize that two sets of social “instincts” underpin and constrain the evolution of complex societies. One set is ancient and shared with other social primate species, and one is derived and unique to our lineage. The latter evolved by the late Pleistocene, and led to the evolution of institutions of intermediate complexity in acephalous societies. The institutions of complex societies often conflict with (...) our social instincts. The complex societies of the past few thousand years can function only because cultural evolution has created effective “work-arounds” to manage such instincts. We describe a series of work-arounds and use the data on the relative effectiveness of WWII armies to test the work-around hypothesis. (shrink)
The complexity of human societies of the past few thousand years rivals that of social insect societies. We hypothesize that two sets of social “instincts” underpin and constrain the evolution of complex societies. One set is ancient and shared with other social primate species, and one is derived and unique to our lineage. The latter evolved by the late Pleistocene, and led to the evolution of institutions of intermediate complexity in acephalous societies. The institutions of complex societies often conflict with (...) our social instincts. The complex societies of the last few thousand years can function only because cultural evolution has created effective “work-arounds” to manage such instincts. We describe a series of work-arounds and use the data on the relative effectiveness of WWII armies to test the work-around hypothesis. (shrink)
Most human populations are subdivided into ethnic groups which have self-ascribed membership and are marked by seemingly arbitrary traits such as distinctive styles of dress or speech. Existing explanations of ethnicity do not adequately explain the origin and maintenance of group marking. Here we develop a mathematical model which shows that groups distinguished by both differences in social norms and in arbitrary markers can emerge and remain stable despite significant mixing between them, if (1) people preferentially interact in mutually beneficial (...) social interaction with people who have the same marker as they do, and (2) they acquire their markers and social behaviors by imitating successful individuals. We also show that the propensity to interact with people with markers like oneself may be favored by natural selection under plausible conditions. (shrink)
Demography plays a large role in cultural evolution through its effects on the effective rate of innovation. If we assume that useful inventions are rare, then small isolated societies will have low rates of invention. In small populations, complex technology will tend to be lost as a result of random loss or incomplete transmission (the Tasmanian effect). Large populations have more inventors and are more resistant to loss by chance. If human populations can grow freely, then a population-technology-population positive feedback (...) should occur such that human societies reach a stable growth path on which the rate of growth of technology is limited by the rate of invention. This scenario fits the Holocene to a first approximation, but the late Pleistocene is a great puzzle. Large-brained hominins existed in Africa and west Eurasia for perhaps 50,000 years with, at best, slow rates of technical innovation. The most sophisticated societies of the last glacial period appear after 50,000 years ago and were apparently restricted to west and north-central Eurasia and North Africa. These patterns have no simple, commonly accepted explanation. We argue that increased high-frequency climate change around 70,000–50,000 years ago may have tipped the balance between humans and their competitor-predators, such as lions and wolves, in favor of humans. At the same time, technically sophisticated hunters would tend to overharvest their prey. Perhaps the ephemeral appearance of complex tools and symbolic artifacts in Africa after 00,000 years ago resulted from hunting inventions that allowed human populations to expand temporarily before prey overexploitation led to human population and technology collapse. Sustained human populations of moderate size using distinctively advanced Upper Paleolithic artifacts may have existed in west Eurasia because cold, continental northeastern Eurasia–Beringia acted as a protected reserve for prey populations. (shrink)
Experiments may contribute to understanding the basic processes of cultural evolution. We drew features from previous laboratory research with small groups in which traditions arose during several generations. Groups of four participants chose by consensus between solving anagrams printed on red cards and on blue cards. Payoffs for the choices differed. After 12 min, the participant who had been in the experiment the longest was removed and replaced with a naı¨ve person. These replacements, each of which marked the end of (...) a generation, continued for 10 – 15 generations, at which time the day’s session ended. Time-out duration, which determined whether the group earned more by choosing red or blue, and which was fixed for a day’s session, was varied across three conditions to equal 1, 2, or 3 min. The groups developed choice traditions that tended toward maximizing earnings. The stronger the dependence between choice and earnings, the stronger was the tradition. Once a choice tradition evolved, groups passed it on by instructing newcomers, using some combination of accurate information, mythology, and coercion. Among verbal traditions, frequency of mythology varied directly with strength of the choice tradition. These methods may be applied to a variety of research questions. D 2004 Elsevier Inc. All rights reserved. (shrink)
Over the past several decades, we have argued that cultural evolution can facilitate the evolution of largescale cooperation because it often leads to more rapid adaptation than genetic evolution, and, when multiple stable equilibria exist, rapid adaptation leads to variation among groups. Recently, Lehmann, Feldman, and colleagues have published several papers questioning this argument. They analyze models showing that cultural evolution can actually reduce the range of conditions under which cooperation can evolve and interpret these models as indicating that we (...) were wrong to conclude that culture facilitated the evolution of human cooperation. In the main, their models assume that rates of cultural adaption are not.. (shrink)
What are the causes of the evolution of complex cognition? Discussions of the evolution of cognition sometimes seem to assume that more complex cognition is a fundamental advance over less complex cognition, as evidenced by a broad trend toward larger brains in evolutionary history. Evolutionary biologists are suspicious of such explanations since they picture natural selection as a process leading to adaptation to local environments, not to progressive trends. Cognitive adaptations will have costs, and more complex cognition will evolve only (...) when its local utility outweighs them. (shrink)
Social institutions are the laws, informal rules, and conventions that give durable structure to social interactions within a population. Such institutions are typically not designed consciously, are heritable at the population level, are frequently but not always group benefi cial, and are often symbolically marked. Conceptualizing social institutions as one of multiple possible stable cultural equilibrium allows a straightforward explanation of their properties. The evolution of institutions is partly driven by both the deliberate and intuitive decisions of individuals and collectivities. (...) The innate components of human psychology coevolved in response to a culturally evolved, institutional environment and refl ect a prosocial tendency of choices we make about institutional forms. (shrink)
The application of phylogenetic methods to cultural variation raises questions about how cultural adaption works and how it is coupled to cultural transmission. Cultural group selection is of particular interest in this context because it depends on the same kinds of mechanisms that lead to tree-like patterns of cultural variation. Here, we review ideas about cultural group selection relevant to cultural phylogenetics. We discuss why group selection among multiple equilibria is not subject to the usual criticisms directed at group selection, (...) why multiple equilibria are a common phenomena, and why selection among multiple equilibria is not likely to be an important force in genetic evolution. We also discuss three forms of group competition and the processes that cause populations to shift from one equilibrium to another and create a mutation-like process at the group level. (shrink)
The existence of social learning has been conﬁrmed in diverse taxa, from apes to guppies. In order to advance our understanding of the consequences of social transmission and evolution of behavior, however, we require statistical tools that can distinguish among diverse social learning strategies. In this paper, we advance two main ideas. First, social learning is diverse, in the sense that individuals can take advantage of diﬀerent kinds of information and combine them in diﬀerent ways. Examining learning strategies for diﬀerent (...) information conditions illuminates the more detailed design of social learning. We construct and analyze an evolutionary model of diverse social learning heuristics, in order to generate predictions and illustrate the impact of design diﬀerences on an organism’s ﬁtness. Second, in order to eventually escape the laboratory and apply social learning models to natural behavior, we require statistical methods that do not depend upon tight experimental control. Therefore we examine strategic social learning in an experimental setting.. (shrink)
MOST MODERN PEOPLE think it is obvious why people become modern. For them, a more interesting and important puzzle is why some people fail to embrace modern ideas. Why do people in traditional societies often seem unable or unwilling to aspire to a better life for themselves and their children? Why do they fail to see the beneﬁ ts of education, equal rights, democracy, and a rational approach to decisionmaking? What is the glue that makes them adhere to superstition, religion, (...) and obligations to family and tribe even if it means accepting a life of insecurity and poverty? The “kin inﬂ uence hypothesis” (Newson et al. 2005) suggests an explanation both for why people become modern and for why modern ideas are often slow to be accepted by a population. The hypothesis is based on the understanding gained by social-psychological research of how cultural norms change. It takes a Darwinian approach to explaining human behavior and recognizes that much of the cultural change associated with modernization is a progressive abandonment of values and norms that encourage people to pursue what evolutionary theorists refer to as “reproductive success.”1 The kin inﬂ uence hypothesis proposes that the cascade of cultural changes associated with modernization is the result of the momentous change in the human social environment that occurs early in economic development. For most of human evolutionary history, the norms of all cultures must have prescribed behavior that, on balance, enhanced the genetic ﬁ tness of their members. If this were not the case, then, as Lumsden and Wilson (1981) and Alexander (1979) rightly pointed out, evolutionary biologists would be unable to explain how humans evolved the uniquely human capacity for learning and imitation that makes culture possible. Nor could we explain how an African ape came to be the world’s dominant organism. With economic development, however, people begin to abandon the beliefs and values that encourage ﬁ tness-enhancing behavior.. (shrink)
Ongoing advances in paleoclimatology and paleoecology are producing an ever more detailed picture of the environments in which our species evolved. This picture is important to understanding the processes by which our large brain evolved. Our large brain and its productions—toolmaking, complex social institutions, language, art, religion—are our most striking differences from our closest living relatives. Indeed, humans are unique in the animal world for our brain size relative to body mass and in the elaboration of our cultures. We are (...) also the world’s dominant organism (Vitousek et al. 1997). We achieved our present anatomy and behavioral repertoire very recently. Fossil material attributable to our species goes back perhaps 200,000 years and artifacts that strike us as representing fully modern behavioral capacities are only about 50,000 years old (Klein 1999; McBrearty and Brooks 2000), about which time anatomically modern humans spread from Africa to Eurasia (Lahr and Foley 1994). Our ecological dominance began with the evolution of agriculture starting about 10,000 years ago. Explaining the late coming of human brains is a major evolutionary puzzle. Most important animal adaptations are old. Eyes, internal skeletons, adaptations for terrestrial life and for flight all date back hundreds of millions of years. Given that big brains and culture were such an overwhelming success for us why didn’t they evolve long ago? (shrink)
What promised to be a refreshing addition to cumulative cultural evolution, by moving the focus from cultural transmission to technological innovation, falls flat through a lack of thoroughness, explanatory power, and data. A comprehensive theory of cumulative cultural change must carefully integrate all existing evidence in a cohesive multi-level account. We argue that the manuscript fails to do so convincingly.
Anthropologists believe that human behavior is governed by culturally transmitted norms, and that such norms contain accumulated wisdom that allows people to behave sensibly even though they do not understand why they do what they do. Economists and other rational choice theorists have been skeptical about functionalist claims because anthropologists have not provided any plausible mechanism which could explain why norms have this property. Here, we outline two such mechanisms. We show that occasional learning when coupled with cultural transmission and (...) a tendency to conform can lead to the spread of sensible norms even though very few people understand why they are sensible. We also show that norms that help solve problems of selfcontrol that arise from time-inconsistent preferences can spread if individuals tend to imitate successful people and are occasionally influenced by members of other groups with different norms. (shrink)
Modern humans are probably a product of social and anatomical preadaptations on the part of our Miocene australopithecine ancestors combined with the increasingly high amplitude, high frequency climate variation of the Pleistocene. The genus Homo first appeared in the early Pleistocene as ice age climates began to grip the earth. We hypothesize that this co-occurrence is causal. The human ability to adapt by cultural means is, in theory, an adaptation to highly variable environments because cultural evolution can better track rapidly (...) changing environments than can genes. High resolution ice and sediment cores published in the early 1990s showed the last ice age was characterized by high amplitude millennial and submillenial scale variation, exactly the sort of variation mathematical models suggest should favor a costly capacity for culture. More recent cores suggest that over the last several 100 thousand year glacial cycles the amount of millennial scale variation has increased rather dramatically in parallel with increases in hominin brain size and sophistication of the artifacts they made. (shrink)
Two kinds of factors set the tempo and direction of organic and cultural evolution, those external to biotic evolutionary process, such as changes in the earth’s physical and chemical environments, and those internal to it, such as the time required for chance factors to lead lineages across adaptive valleys to a new niche space (Valentine 1985). The relative importance of these two sorts of processes is widely debated. Valentine (1973) argued that marine invertebrate diversity patterns responded to seafloor spreading as (...) this process generated more or less niche space. He suggested that natural selection is a powerful force and that earth’s biota are in near equilibrium with the niches available on the geological time scale. Walker and Valentine (1984) modeled the evolution of species assuming a logistic speciation rate limited by internal factors and a diversity-independent death rate caused by ongoing environmental change. Fitting this model to the observed evolution of shelled marine invertebrates suggests that the lag between extinctions and the evolution of new species leaves perhaps 30% of ecological niches unfilled. In this model, the biota lag environmental change by perhaps a few million years. However, as Valentine (1985) notes, if adaptive landscapes have whole suites of niches protected by deep maladaptive valleys, the waiting time for some pioneering species to cross the divide may be very long, generating the rare events that set new body plans and generate major adaptive radiations. Eldredge and Gould (1972) and Gould (2002) championed the idea that internal processes such as genetic and developmental constraints, coupled with the complexity of the adaptive landscape, resulted in a highly historically contingent evolutionary process. On Gould’s account, most of the history of life had to do not with a relatively close tracking of a changing environment but with the halting evolutionary exploration a deeply fissured niche space, mostly by rapid bursts of evolution as a fissure was crossed, followed by long periods of stasis.. (shrink)
Biology and the social sciences share an interest in phylogeny. Biologists know that living species are descended from past species, and use the pattern of similarities among living species to reconstruct the history of phylogenetic branching. Social scientists know that the beliefs, values, practices, and artifacts that characterize contemporary societies are descended from past societies, and some social science disciplines, linguistics and cross cultural anthropology for example, have made use of observed similarities to reconstruct cultural histories. Darwin appreciated that his (...) theory of descent with modification had many similarities of pattern and process to the already well developed field of historical linguistics. In many other areas of social science, however, phylogenetic reconstruction has not played a central role. (shrink)
Experiments are not models of cooperation; instead, they demonstrate the presence of the ethical and other-regarding predispositions that often motivate cooperation and the punishment of free-riders. Experimental behavior predicts subjects' cooperation in the field. Ethnographic studies in small-scale societies without formal coercive institutions demonstrate that disciplining defectors is both essential to cooperation and often costly to the punisher.
Darwin believed that his theory of evolution would stand or fall on its ability to account for human behavior. No species could be an exception to his theory without imperiling the whole edifice. The ideas in the Descent of Man were widely discussed by his contemporaries although they were far from being the only evolutionary theories current in the late nineteenth century. Darwin's specific evolutionary ideas and those of his main followers had very little impact on the social sciences as (...) they emerged as separate disciplines in the early Twentieth Century. Not until the late twentieth century were concerted, sophisticated efforts made to apply Darwinian theory to human behavior. Why such a long delay? We argue that Darwin's theory was rather modern in respects that conflicted with Victorian sensibilities and that he and his few close followers failed to influence any of the social sciences. The late Twentieth Century work takes up almost exactly where James Baldwin left off at the turn of the century. (shrink)
Human syntactic language has no close parallels in other systems of animal communication. Yet it seems to be an important part of the cultural adaptation that serves to make humans the earth’s dominant organism. Why is language restricted to humans given that communication seems to be so useful? We argue that language is part of human cooperation. We talk because others can normally trust what we say to be useful to them, not just to us. Models of gene-culture coevolution give (...) one plausible explanation for how language, cooperative institutions, and the genetic basis for both could have evolved. Why did the coevolutionary process come to rest leaving a huge space for the cultural evolution of language? We argue that language diversity functions to limit communication between people who cannot freely trust one another or where even truthful communications from others would result in maladaptive behavior on the part of listeners. (shrink)
We propose a general framework for integrating theory and empiricism in human evolutionary ecology. We specifically emphasize the joint use of stochastic nonlinear dynamics and information theory. To illustrate critical ideas associated with historical contingency and complex dynamics, we review recent research on social preferences and social learning from behavioral economics. We additionally examine recent work on ecological approaches in history, the modeling of chaotic populations, and statistical application of information theory.
Rates of violence in the American South have long been much greater than in the North. Accounts of duels, feuds, bushwhackings, and lynchings occur prominently in visitors’ accounts, newspaper articles, and autobiography from the 18th Century onward. According to crime statistics these differences persist today. In their book, Culture of Honor, Richard Nisbett and Dov Cohen argue that the South is more violent than the North because Southerners have different, culturally acquired beliefs about personal honor than Northerners. The South was (...) disproportionately settled by Protestant Scotch-Irish, people with an animal herding background, whereas Northern settlers were English, German and Dutch peasant farmers. Most herders live in thinly settled, lawless regions. Since livestock are easy to steal, herders seek reputations for willingness to engage in violent behavior as a deterrent to rustling and other predatory behavior. Of course, bad men come to subscribe to the same code, the better to intimidate their victims. As this arms race proceeds, arguments over trivial acts can rapidly escalate if a man—less often a woman—thinks his honor is at stake, and the resulting “culture of honor” leads to high rates of violence. Nisbett and Cohen support their hypothesis with an impressive range of data including, laboratory data, attitude surveys, field experiments, data on violence, and differences in legal codes. (shrink)
Free enterprise economic systems evolved in the modern period as culturally transmitted values related to honesty, hard work, and education achievement emerged. One evolutionary puzzle is why most economies for the past 5,000 years have had a limited role for free enterprise given the spectacular success of modern free economies. Another is why if humans became biologically modern 50,000 years ago did it take until 11,000 years ago for agriculture, the economic foundation of states, to begin. Why didn’t free enterprise (...) evolve long ago and far away? (shrink)
Humans hunt and kill many different species of animals, but whales are our biggest prey. In the North Atlantic, a male long-ﬁ nned pilot whale (Globiceph- ala melaena), a large relative of the dolphins, can grow as large as 6.5 meters and weigh as much as 2.5 tons. As whales go, these are not particularly large, but there are more than 750,000 pilot whales in the North Atlantic, traveling in groups, “pods,” that range from just a few individuals to a (...) thousand or more. Each pod is led by an individual known as the “pilot,” who appears to set the course of travel for the rest of the group. This pilot is both an asset and a weakness to the pod. The average pilot whale will yield about a half ton of meat and blubber, and North Atlantic societies including Ireland, Iceland, and the Shetlands used to manipulate the pilot to drive the entire pod ashore. In the Faroe Islands, a group of 18 grassy rocks due north of Scotland, pilot whale hunts have continued for the last 1200 years, at least. The permanent residents of these islands, the Faroese, previously killed an average of 900 whales each year, yielding about 500 tons of meat and fat that was consumed by local residents. Hunts have declined in recent years. From 2001 to 2005, about 3400 whales were killed, yielding about 890 metric tons of blubber and 990 metric tons of meat. The whale kill, or grindadráp in the Faroese language, begins when a ﬁ shing boat spots a pod close enough to a suitable shore, on a suitably clear day. A single boat, or even a small group of ﬁ shermen, is not sufﬁ cient to trap a.. (shrink)
Human migration is nonrandom. In small scale societies of the past, and in the modern world, people tend to move to wealthier, safer, and more just societies from poorer, more violent, less just societies. If immigrants are assimilated, such nonrandom migration can increase the occurrence of culturally transmitted beliefs, values, and institutions that cause societies to be attractive to immigrants. Here we describe and analyze a simple model of this process. This model suggests that long run outcomes depend on the (...) relative strength of migration and local adaptation. When local adaption is strong enough to preserve cultural variation among groups, cultural variants that make societies attractive always predominate, but never drive alternative variants to extinction. When migration predominates, outcomes depend both on the relative attractiveness of alError: Illegal entry in bfrange block in ToUnicode CMapError: Illegal entry in bfrange block in ToUnicode CMapError: Illegal entry in bfrange block in ToUnicode CMapError: Illegal entry in bfrange block in ToUnicode CMapError: Illegal entry in bfrange block in ToUnicode CMapError: Illegal entry in bfrange block in ToUnicode CMapError: Illegal entry in bfrange block in ToUnicode CMapError: Illegal entry in bfrange block in ToUnicode CMapError: Illegal entry in bfrange block in ToUnicode CMapError: Illegal entry in bfrange block in ToUnicode CMapError: Illegal entry in bfrange block in ToUnicode CMapError: Illegal entry in bfrange block in ToUnicode CMapError: Illegal entry in bfrange block in ToUnicode CMapError: Illegal entry in bfrange block in ToUnicode CMapError: Illegal entry in bfrange block in ToUnicode CMapError: Illegal entry in bfrange block in ToUnicode CMapternative variants and on the initial sizes of societies that provide and receive immigrants. (shrink)
In this paper, we analyze a sample of 46 ethnic boundaries drawn from the literature. The principal aim is to test whether there is a universal syndrome of ethnocentrism, the idea that ethnic relations can be characterized along a single dimension of differences, or, whether there are instead multiple types of ethnic relations. The latter hypothesis is based on a cultural evolutionary perspective that suggests that there may be competing forces leading to the evolution of ethnic markers, and hence to (...) the possibility that ethnicity is a multi-dimensional phenomenon. These competing forces may yield a variety of types of ethnic boundaries, not all of which may be conflictual. Thus, we also examine what factors do most closely correlate with violent conflict. (shrink)
As cultural evolutionists interested in how culture changes over the long term, we've thought and written a lot about migration, but only recently tumbled to an obvious idea: migration has a profound effect on how societies evolve culturally because it is selective. People move to societies that provide a more attractive way of life, and all other things being equal, this process spreads ideas and institutions that lead to economic efficiency, social order and equality.
This paper relates firm size and opportunism by showing that, given certain behavioral dispositions of humans, the size of a profit-maximizing firm can be determined by cognitive aspects underlying firminternal cultural transmission processes. We argue that what firms do better than markets – besides economizing on transaction costs – is to establish a cooperative regime among its employees that keeps in check opportunism. A model depicts the outstanding role of the entrepreneur or business leader in firminternal socialization processes and the (...) evolution of corporate cultures. We show that high opportunismrelated costs are a reason for keeping firms’ size small. (shrink)