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)
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)
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)
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.
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)
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 (1996) 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)
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)
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)
Approach and avoidance motivation may represent important explanatory constructs in understanding how individuals differ. Such constructs have primarily been assessed in self-reported terms, but there are limitations to self-reports of motivation. Accordingly, the present review concentrates on the potential utility of implicit cognitive-behavioral probes of approach and avoidance motivation in modeling and understanding individual differences. The review summarizes multiple lines of research that have documented the utility of such probes to the personality-processing interface. Although multiple gaps in our knowledge exist, (...) and are acknowledged, the value of such implicit cognitive-behavioral assessments is emphasized both in modeling multiple subcomponents of approach and avoidance motivation and in showing that such tendencies matter in ways that transcend momentary experiences or manipulations. (shrink)
Recent debates about memetics have revealed some widespread misunderstandings about Darwinian approaches to cultural evolution. Drawing from these debates, this paper disputes five common claims: (1) mental representations are rarely discrete, and therefore models that assume discrete, gene-like particles (i.e., replicators) are useless; (2) replicators are necessary for cumulative, adaptive evolution; (3) content-dependent psychological biases are the only important processes that affect the spread of cultural representations; (4) the “cultural fitness” of a mental representation can be inferred from its successful (...) transmission; and (5) selective forces only matter if the sources of variation are random. We close by sketching the outlines of a unified evolutionary science of culture. (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)
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)
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)
We would like to thank the commentators for their generous comments, valuable insights and helpful suggestions. We begin this response by discussing the selfishness axiom and the importance of the preferences, beliefs, and constraints framework as a way of modeling some of the proximate influences on human behavior. Next, we broaden the discussion to ultimate-level (that is evolutionary) explanations, where we review and clarify gene-culture coevolutionary theory, and then tackle the possibility that evolutionary approaches that exclude culture might be sufficient (...) to explain the data. Finally, we consider various methodological and epistemological concerns expressed by our commentators. (shrink)
Researchers from across the social sciences have found consistent deviations from the predictions of the canonical model of self-interest in hundreds of experiments from around the world. This research, however, cannot determine whether the uniformity results from universal patterns of human behavior or from the limited cultural variation available among the university students used in virtually all prior experimental work. To address this, we undertook a cross-cultural study of behavior in ultimatum, public goods, and dictator games in a range of (...) small-scale societies exhibiting a wide variety of economic and cultural conditions. We found, first, that the canonical model – based on self-interest – fails in all of the societies studied. Second, our data reveal substantially more behavioral variability across social groups than has been found in previous research. Third, group-level differences in economic organization and the structure of social interactions explain a substantial portion of the behavioral variation across societies: the higher the degree of market integration and the higher the payoffs to cooperation in everyday life, the greater the level of prosociality expressed in experimental games. Fourth, the available individual-level economic and demographic variables do not consistently explain game behavior, either within or across groups. Fifth, in many cases experimental play appears to reflect the common interactional patterns of everyday life. Key Words: altruism; cooperation; cross-cultural research; experimental economics; game theory; ultimatum game; public goods game; self-interest. (shrink)
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)
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)
Human societies are extraordinarily cooperative compared to those of most other animals. In the vast majority of species, individuals live solitary lives, meeting to only to mate and, sometimes, raise their young. In social species, cooperation is limited to relatives and (maybe) small groups of reciprocators. After a brief period of maternal support, individuals acquire virtually all of the food that they eat. There is little division of labor, no trade, and no large scale conflict. Communication is limited to a (...) small repertoire of self-verifying signals. No one cares for the sick, or feeds the hungry or disabled. The strong take from the weak without fear of sanctions by third parties. Amend Hobbes to account for nepotism, and his picture of the state of nature is not so far off for most other animals. In contrast, people in even the simplest human societies regularly cooperate with many unrelated individuals. Human language allows low-cost honest communication of virtually unlimited complexity. The sick are cared for, and sharing leads to substantial flows of food from the middle aged to the young and old. Division of labor and trade are prominent features of every historically known human society, and archaeology indicates that they have a long history. Violent conflict among sizable groups is common. In every human society, social life is regulated by commonly held moral systems that specify the rights and duties of individuals enforced, albeit imperfectly, by third party sanctions. (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)
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 alternative variants and on the initial sizes of societies that provide and receive immigrants. (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)
It is often argued that culture is adaptive because it allows people to acquire useful information without costly learning. In a recent paper Rogers (1989) 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)
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..
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.