Identifying the determinants of reproductive success in small-scale societies is critical for understanding how natural selection has shaped human evolution and behavior. The available evidence suggests that status-accruing behaviors such as hunting and prosociality are pathways to reproductive success, but social egalitarianism may diminish this pathway. Here we introduce a mixed longitudinal/cross-sectional dataset based on 45 years of research with the Batek, a population of egalitarian rain forest hunter-gatherers in Peninsular Malaysia, and use it to test the effects (...) of four predictors of lifetime reproductive success: foraging return rate, sharing proclivity, cooperative foraging tendency, and kin presence. We found that none of these factors can explain variation in lifetime reproduction among males or females. We suggest that social egalitarianism, combined with strikingly low infant and juvenile mortality rates, can mediate the pathway between foraging, status-accruing behavior, and reproductive success. Our approach advocates for greater theoretical and empirical attention to quantitative social network measures, female foraging, and fitness outcomes. (shrink)

The literature on human mate preferences is vast but most data come from studies on college students in complex societies, who represent a thin slice of cultural variation in an evolutionarily novel environment. Here, I present data on the mate preferences of men and women in a society of hunter-gatherers, the Hadza of Tanzania. Hadza men value fertility in a mate more than women do, and women value intelligence more than men do. Women place great importance on men’s (...) foraging, and both sexes rate character as important. Unlike college students, Hadza men place considerable importance on women being hard-working, and Hadza women cite looks about as often as men do. (shrink)

Hunting and gathering is, evolutionarily, the defining subsistence strategy of our species. Studying how children learn foraging skills can, therefore, provide us with key data to test theories about the evolution of human life history, cognition, and social behavior. Modern foragers, with their vast cultural and environmental diversity, have mostly been studied individually. However, cross-cultural studies allow us to extrapolate forager-wide trends in how, when, and from whom hunter-gatherer children learn their subsistence skills. We perform a meta-ethnography, which (...) allows us to systematically extract, summarize, and compare both quantitative and qualitative literature. We found 58 publications focusing on learning subsistence skills. Learning begins early in infancy, when parents take children on foraging expeditions and give them toy versions of tools. In early and middle childhood, children transition into the multi-age playgroup, where they learn skills through play, observation, and participation. By the end of middle childhood, most children are proficient food collectors. However, it is not until adolescence that adults (not necessarily parents) begin directly teaching children complex skills such as hunting and complex tool manufacture. Adolescents seek to learn innovations from adults, but they themselves do not innovate. These findings support predictive models that find social learning should occur before individual learning. Furthermore, these results show that teaching does indeed exist in hunter-gatherer societies. And, finally, though children are competent foragers by late childhood, learning to extract more complex resources, such as hunting large game, takes a lifetime. (shrink)

Hunter-gatherer punishment involves costs and benefits to individuals and groups, but the costs do not necessarily fit with the assumptions made in models that consider punishment to be altruistic – which brings in the free-rider problem and the problem of second-order free-riders. In this commentary, I present foragers' capital punishment patterns ethnographically, in the interest of establishing whether such punishment is likely to be costly; and I suggest that in many cases abstentions from punishment that might be taken (...) as defections by free-riders are actually caused by social-structural considerations rather than being an effect of free-rider genes. This presentation of data supplements the ethnographic analysis provided by Guala. (shrink)

Sex differences in physical and indirect aggression have been found in many societies but, to our knowledge, have not been studied in a population of hunter-gatherers. Among Aka foragers of the Central African Republic we tested whether males physically aggressed more than females, and whether females indirectly aggressed more than males, as has been seen in other societies. We also tested predictions of an evolutionary theory of physical strength, anger, and physical aggression. We found a large male (...) bias in physical aggression. Controlling for anger, we found an adult female bias in indirect aggression. Physical strength predicted anger, which predicted hitting, although results were sensitive to the inclusion or exclusion of traditional healers, who were physically and emotionally distinct from other Aka. With some important caveats, our results generally support the predicted sex differences in physical aggression and indirect aggression, and the predicted relationships among anger, strength, and aggression. (shrink)

Dispersal of individuals from their natal communities at sexual maturity is an important determinant of kin association. In this paper we compare postmarital residence patterns among Pumé foragers of Venezuela to investigate the prevalence of sex-biased vs. bilateral residence. This study complements cross-cultural overviews by examining postmarital kin association in relation to individual, longitudinal data on residence within a forager society. Based on cultural norms, the Pumé have been characterized as matrilocal. Analysis of Pumé marriages over a 25-year period (...) finds a predominant pattern of natalocal residence. We emphasize that natalocality, bilocality, and multilocality accomplish similar ends in maximizing bilateral kin affiliations in contrast to sex-biased residential patterns. Bilateral kin association may be especially important in foraging economies where subsistence activities change throughout the year and large kin networks permit greater potential flexibility in residential mobility. (shrink)

Research in nonindustrial small-scale societies challenges the common perception that human childhood is universally characterized by a long period of intensive adult investment and dedicated instruction. Using return rate and time allocation data for the Savanna Pumé, a group of South American hunter-gatherers, age patterns in how children learn to become productive foragers and from whom they learn are observed across the transition from childhood to adolescence. Results show that Savanna Pumé children care for their siblings, are (...) important economic contributors, learn by doing rather than by instruction, and spend their time principally in the company of other children. This developmental experience contrasts with that of children in postindustrial societies, who are dependent on adults, often well past maturity; learn in formal settings; and spend much of their time in the company of adults. These differences raise questions about whether normative behaviors observed in postindustrial societies are representative of human children. This comparison also identifies the potential mismatch between hunter-gatherer and postindustrial societies in the extent to which children may be well adapted to learn from and teach each other. In particular, spending time in autonomous work and play groups develops the cooperation and coordination skills that are foundational to human subsistence and growing up to be socially and productively adept adults and parents. (shrink)

This chapter compares the social behaviour of human hunter-gatherers with that of the better-studied chimpanzee species, Pan troglodytes, in an attempt to pinpoint the unique features of human social evolution. Although hunter-gatherers and chimpanzees living in central Africa have similar body weights, humans live at much lower population densities due to their greater dependence on predation. Human foraging parties have longer duration than those of chimpanzees, lasting hours rather than minutes, and a higher level of mutual (...) dependence, through the division of labour between men and women ; which is in turn related to pair-bonding, and meat sharing to reduce the risk of individual hunters' failure on any particular day. The band appears to be a uniquely human social unit that resolves the tension between greater dispersion and greater interdependence. (shrink)

In the developing world, the dramatic male bias in tobacco use is usually ascribed to pronounced gender disparities in social, political, or economic power. This bias might also reflect under-reporting by woman and/or over-reporting by men. To test the role of gender inequality on gender differences in tobacco use we investigated tobacco use among the Aka, a Congo Basin foraging population noted for its exceptionally high degree of gender equality. We also tested a sexual selection hypothesis—that Aka men’s tobacco use (...) is related to risk taking. Tobacco use, income, tobacco purchases, tobacco sharing, reasons for using tobacco, risk taking, and other variables were measured using structured surveys and peer reports. Tobacco use was verified by testing for salivary cotinine, a nicotine metabolite. Contrary to expectations, we found a very large male bias in tobacco use. Low levels of use among females appeared to be explained by aversions to tobacco, concerns over its negative effects on fetal health, and a desire to attract husbands, who prefer nonsmoking wives. High male use appeared to be related to a desire to enhance hunting abilities and attract and/or retain wives, who prefer husbands that smoke. We conclude that low levels of smoking by Aka women are better explained by the hypothesis that women evolved to avoid plant toxins to protect their fetuses and nursing infants. High male use might be better explained by sexual selection. We also highlight the important role that recreational drugs appear to play in hunter-gatherer sharing relationships. (shrink)

Many have interpreted symbolic material culture in the deep past as evidencing the origins sophisticated, modern cognition. Scholars from across the behavioural and cognitive sciences, including linguists, psychologists, philosophers, neuroscientists, primatologists, archaeologists and paleoanthropologists have used such artefacts to assess the capacities of extinct human species, and to set benchmarks, milestones or otherwise chart the course of human cognitive evolution. To better calibrate our expectations, the present paper instead explores the material culture of three contemporary African forager groups. Results show (...) that, while these groups are unequivocally behaviourally modern, they would leave scant long-lasting evidence of symbolic behaviour. Artefact-sets are typically small, perhaps as consequence of residential mobility. When excluding traded materials, few artefacts have components with moderate-strong taphonomic signatures. Present analyses show that artefact function influences preservation probability, such that utilitarian tools for the processing of materials and the preparation of food are disproportionately likely to contain archaeologically traceable components. There are substantial differences in material-use between populations, which create important population-level variation preservation probability independent of cognitive differences. I discuss the factors — cultural, ecological and practical — that influence material choice. In so doing, I highlight the difficulties of using past material culture as an evolutionary or cognitive yardstick. (shrink)

Even though female food acquisition is an area of considerable interest in hunter-gatherer research, the ecological determinants of women’s economic decisions in these populations are still poorly understood. The literature on female foraging behavior indicates that there is considerable variation within and across foraging societies in the amount of time that women spend foraging and in the amount and types of food that they acquire. It is possible that this heterogeneity reflects variation in the trade-offs between time spent in (...) food acquisition and child care activities that women face in different groups of hunter-gatherers. In this paper we discuss the fitness trade-offs between food acquisition and child care that Hiwi and Ache women foragers might face. Multiple regression analyses show that in both populations the daily food acquisition of a woman’s spouse is negatively related to female foraging effort. In addition, nursing mothers spend less time foraging and acquire less food than do nonnursing women. As the number of dependents that a woman has increases, however, women also increase foraging time and the amount of food they acquire. Some interesting exceptions to these general trends are as follows: (a) differences in foraging effort between nursing and nonnursing women are less pronounced when fruits and roots are in season than in other seasons of the year; (b) foraging return rates decrease for Ache women as their numbers of dependents increase; and (c) among Ache women, the positive effect of number of dependents on foraging behavior is less pronounced when fruits are in season than at other times of the year. Lastly, in the Hiwi sample we found that postreproductive women work considerably harder than women of reproductive age in the root season but not in other seasons of the year. We discuss how ecological variation in constraints, the number of health insults to children that Hiwi and Ache mothers can avoid, and the fitness benefits they can gain from spending time in food acquisition and child care might account for differences and similarities in the foraging behaviors of subgroups of Hiwi and Ache mothers across different seasons of the year. Valid tests of the explanations we propose will require considerable effort to measure the relationship between maternal food acquisition, child care, and adverse health outcomes in offspring. (shrink)

This paper presents quantitative data on altruistic cooperation during food acquisition by Ache foragers. Cooperative activities are defined as those that entail a cost of time and energy to the donor but primarily lead to an increase in the foraging success of the recipient. Data show that Ache men and women spend about 10% of all foraging time engaged in altruistic cooperation on average, and that on some days they may spend more than 50% of their foraging time in (...) such activities. The most time-consuming cooperative activity for both sexes is helping during the pursuit of game animals, a pattern that is probably linked to the widespread sharing of game by Ache foragers. Cooperative food acquisition and subsequent food redistribution in hunter-gatherer societies are critical behaviors that probably helped shape universal, evolved, cooperative tendencies that are well illustrated in modern experimental economics. (shrink)

This paper presents a stylized bioeconomic model of hunter-gatherer foraging effort designed to study the process of intensification on open-access resources. A critical insight derived from the model is that the very success of an adaptation at the level of an individual forager group can create system-level vulnerabilities that subsequently feed back to cause emergent social change. The model illustrates how the intensification of harvest time by individuals within a habitat creates a forager-resource system that becomes vulnerable to perturbations. (...) When the system is vulnerable, it is characterized by two resource harvest equilibria: a sustainable, low-effort equilibrium and a degraded, high-effort equilibrium. In this situation, the forager-resource system can be shocked back and forth between these different equilibria by perturbations, generating considerable risk for foragers. We use the model to isolate the ecological conditions under which the instability of the system generates the risk that foragers will experience a shortfall of resources, and we suggest a mechanism that might lead foragers to adopt social institutions that regulate who can access a habitat as an adaptive response. As an illustration of the potential utility of the insights drawn from the model, comparisons are made with a substantial ethnographic data set. (shrink)

We are economists with a long-standing interest in evolutionary psychology, who recently came to appreciate the rich collections of relevant data cultural anthropologists have spent decades collecting on the social environments of a wide range of human societies. While we found some systematic collections of these observations, we could not find a systematic summary of the social environment of the subsample of societies that most resemble the social environment where most human psychology seems to have evolved: small bands of nomadic (...) foragers. This short paper therefore represents our attempt to create such a summary. Using an existing dataset aggregated from diverse ethnographies, we collect statistics on the social environment of the studied cultures which most closely resemble our hunter-gatherer ancestors. Compared with relatively modern societies, nomadic foragers had similar levels of food and disease, and less murder and suicide. They did not fight over land or resources, and they enforced justice directly and personally. They avoided class divisions like rich vs. poor, shared food more, and their leaders had no formal powers. Polygamy, premarital sex, and extramarital sex were all widespread, divorce was easy, and men and women were generally considered equal. Kids were taught to be more generous, trusting, and honest, and were never punished physically. (shrink)

This paper presents quantitative data on altruistic cooperation during food acquisition by Ache foragers. Cooperative activities are defined as those that entail a cost of time and energy to the donor but primarily lead to an increase in the foraging success of the recipient. Data show that Ache men and women spend about 10% of all foraging time engaged in altruistic cooperation on average, and that on some days they may spend more than 50% of their foraging time in (...) such activities. The most time-consuming cooperative activity for both sexes is helping during the pursuit of game animals, a pattern that is probably linked to the widespread sharing of game by Ache foragers. Cooperative food acquisition and subsequent food redistribution in hunter-gatherer societies are critical behaviors that probably helped shape universal, evolved, cooperative tendencies that are well illustrated in modern experimental economics. (shrink)

Imaginary worlds recur across hunter-gatherer narrative, suggesting that they are an ancient part of human life: to understand their popularity, we must examine their origins. Hunter-gatherer fictional narratives use various devices to encode factual information. Thus, participation in these invented worlds, born of our evolved ability to engage in pretense, may provide adaptations with information inputs that scaffold their development.

There is a popular idea that archaic humans commonly used wooden clubs as their weapons. This is not based on archaeological finds, which are minimal from the Pleistocene, but rather on a few ethnographic analogies and the association of these weapons with simple technology. This article presents the first quantitative cross-cultural analysis of the use of wooden clubs and throwing sticks for hunting and violence among foragers. Using a sample of 57 recent hunting-gathering societies from the Standard Cross-Cultural Sample, (...) it is shown that the majority used clubs for violence (86%) and/or hunting (74%). Whereas in hunting and fishing the club usually served only as a secondary tool, 33% of societies used the club as one of their main fighting weapons. The use of throwing sticks was less frequent among the societies surveyed (12% for violence, 14% for hunting). Based on these results and other evidence, it is argued that the use of clubs by early humans was highly probable, at least in the simplest form of a crude stick. The great variation in the forms and use of clubs and throwing sticks among recent hunter-gatherers, however, indicates that they are not standardized weapons and that similar variation may have existed in the past. Many such prehistoric weapons may therefore have been quite sophisticated, multifunctional, and carried strong symbolic meaning. (shrink)

A fact of life for farmers, hunter-gatherers, and fishermen in the rural parts of the world are that crops fail, wild resources become scarce, and winds discourage fishing. In this article we approach subsistence risk from the perspective of "coexistence thinking," the simultaneous application of natural and supernatural causal models to explain subsistence success and failure. In southwestern Madagascar, the ecological world is characterized by extreme variability and unpredictability, and the cosmological world is characterized by anxiety about supernatural (...) dangers. Ecological and cosmological causes seem to point to different risk minimizing strategies: to avoid losses from drought, flood, or heavy winds, one should diversify activities and be flexible; but to avoid losses caused by disrespected spirits one should narrow one's range of behaviors to follow the code of taboos and offerings. We address this paradox by investigating whether southwestern Malagasy understand natural and supernatural causes as occupying separate, contradictory explanatory systems (target dependence), whether they make no categorical distinction between natural and supernatural forces and combine them within a single explanatory system (synthetic thinking), or whether they have separate natural and supernatural categories of causes that are integrated into one explanatory system so that supernatural forces drive natural forces (integrative thinking). Results from three field studies suggest that (a) informants explain why crops, prey, and market activities succeed or fail with reference to natural causal forces like rainfall and pests, (b) they explain why individual persons experience success or failure primarily with supernatural factors like God and ancestors, and (c) they understand supernatural forces as driving natural forces, so that ecology and cosmology represent distinct sets of causes within a single explanatory framework. We expect that future cross-cultural analyses may find that this form of "integrative thinking" is common in unpredictable environments and is a cognitive strategy that accompanies economic diversification. (shrink)

We use data collected among Hadza hunter-gatherers between 2005 and 2009 to examine hypotheses about the causes and consequences of men’s foraging and food sharing. We find that Hadza men foraged for a range of food types, including fruit, honey, small animals, and large game. Large game were shared not like common goods, but in ways that significantly advantaged producers’ households. Food sharing and consumption data show that men channeled the foods they produced to their wives, children, and (...) their consanguineal and affinal kin living in other households. On average, single men brought food to camp on 28% of days, married men without children at home on 31% of days, and married men with children at home on 42% of days. Married men brought fruit, the least widely shared resource, to camp significantly more often than single men. A model of the relationship between hunting success and household food consumption indicates that the best hunters provided 3–4 times the amount of food to their families than median or poor hunters. These new data fill important gaps in our knowledge of the subsistence economy of the Hadza and uphold predictions derived from the household and kin provisioning hypotheses. Key evidence and assumptions backing prior claims that Hadza hunting is largely a form of status competition were not replicated in our study. In light of this, family provisioning is a more viable explanation for why good hunters are preferred as husbands and have higher fertility than others. (shrink)

Humans have a much longer juvenile period (weaning to first reproduction, 14 or more years) than their closest relatives (chimpanzees, 8 years). Three explanations are prominent in the literature. (a) Humans need the extra time to learn their complex subsistence techniques. (b) Among mammals, since length of the juvenile period bears a constant relationship to adult lifespan, the human juvenile period is just as expected. We therefore only need to explain the elongated adult lifespan, which can be explained by the (...) opportunity for older individuals to increase their fitness by providing for grandchildren. (c) The recent model by Kaplan and colleagues suggests that longevity and investment in "embodied capital" will coevolve, and that the need to learn subsistence technology contributed to selection for our extended lifespan.We report experiments designed to test the first explanation: human subsistence technology takes many years to learn, and spending more time learning it gives reproductive benefits that outweight lost time. Taking away some of this time should lead to deficits in efficiency. We paid Hadza foragers to participate in tests of important subsistence skills. We compared efficiency of males and females at digging tubers. They differ greatly in time spent practicing digging but show no difference in efficiency. Children who lost "bush experience" by spending years in boarding school performed no worse at digging tubers or target archery than those who had spent their entire lives in the bush. Climbing baobab trees, an important and dangerous skill, showed no change with age among those who attempted it. We could show no effects of practice time.These findings do not support what we label "the practice theory," but we discuss ways in which the theory could be defended; for example, some as-yet-untested skill may be greatly impaired by loss of a few years of the juvenile period. Our data also show that it is not safe to assume that increases in skill with age are entirely due to learning or practice; they may instead be due to increases in size and strength. (shrink)

Attention has been given to cross-cultural differences in adolescent growth, but far less is known about developmental variability during juvenility (ages 3–10). Previous research among the Pumé, a group of South American foragers, found that girls achieve a greater proportion of their adult stature during juvenility compared with normative growth expectations. To explain rapid juvenile growth, in this paper we consider girls’ activity levels and energy expended in subsistence effort. Results show that Pumé girls spend far less time in (...) subsistence tasks in proportion to their body size compared with adults, and they have lower physical activity levels compared with many juveniles cross-culturally. Low activity levels help to explain where the extra energy comes from to support rapid growth in a challenging environment. We suggest that activity levels are important to account for the variation of resource and labor transfers in mediating energy availability. (shrink)

This article seeks to identify at what point in hominid evolution language would have become adaptive. It starts by recalling the distinction between kin-selected altruism and reciprocal altruism, noting that the former is characteristic of social insects while the latter is found among some species of social mammal. Reciprocal altruism depends on the exchange of information assuring partners of the other’s continued friendly intent, as in the iterated prisoner’s dilemma. The article focuses on species that practice “fission–fusion”: social behaviour, where (...) the alternation between larger and smaller parties creates greater uncertainty as to individuals’ continued commitment to reciprocity. The greatest uncertainty arises in “atomistic” fission–fusion, where individuals leave and join foraging groups independently. Chimpanzees, bonobos, and human hunter–gatherers practice this type of social behaviour. There is less uncertainty where the smaller social unit is an extended family, as among vampire bats, chacma baboons, and savanna elephants. A comparison of the repertoire of calls and gestures among these species indicates that chimpanzees and bonobos have the largest repertoires. I then point out that, thanks to the higher proportion of meat in the diet, hunter–gatherers must live in far more dispersed communities than chimpanzees or bonobos, yet they practice more complex patterns of cooperation and reciprocity. This, I argue, created a social environment in which language became particularly adaptive. Homo heidelbergensis is identified as the key species in which language could have originated, during the transition between the Lower and Middle Paleolithic. (shrink)

Dyadic play fighting occurs in many species, but only humans are known to engage in coalitional play fighting. Dyadic play fighting is hypothesized to build motor skills involved in actual dyadic fighting; thus, coalitional play fighting may build skills involved in actual coalitional fighting, operationalized as forager lethal raiding. If human psychology includes a motivational component that encourages engagement in this type of play, evidence of this play in forager societies is necessary to determine that it is not an artifact (...) of agricultural or industrial conditions. We examine whether coalitional play fighting appears in the hunter-gatherer record and includes motor skills used in lethal raiding. Using the ethnographic record, we generated a list of motor patterns regularly used in forager warfare. Then, using Murdock’s Ethnographic Atlas, we identified 100 culture clusters containing forager societies and searched the ethnographic records of these societies for descriptions of coalitional play fighting, operationalized as contact games played in teams. Resulting games were coded for the presence of eight motor patterns regularly used in forager lethal raiding. Although play does not tend to be systematically documented in the hunter-gatherer literature, sufficiently detailed descriptions of coalitional play were found for 46 of the 100 culture clusters: all 46 exhibited coalitional play using at least one of the predicted motor patterns; 39 exhibited coalitional play using four or more of the eight predicted motor patterns. These results provide evidence that coalitional play fighting occurs across a diverse range of hunter-gatherer cultures and habitats, regularly recruits motor patterns used in lethal raiding, and is not an artifact of agricultural or industrial life. This is a first step in a new line of research on whether human male psychology includes motivations to engage in play that develops the deployment of coordinated coalitional action involving key motor patterns used in lethal raiding. (shrink)

The human population grew at very low average rates for most of its existence. Mortality was reasonably severe and expectation of life at birth was low. The level of fertility necessary to achieve even inifinitesimal population growth under such mortality implies birth intervals sufficiently short to conflict with the ability to care for and carry children in a mobile foraging economy. Techniques for the control of mortality, especially of children before puberty and of women in childbirth, and of child care (...) exchange, probably developed by females, may have been essential in permitting population growth under conditions of mobile foraging. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:The Human Revolution and the Adaptive Function of LiteratureJoseph CarrollIBefore the advent of purely culturalist ways of thinking in the early decades of the twentieth century, the idea of "human nature" was deeply ingrained in the literature and the humanistic social theory of the West.1 In the past three decades, ethology, sociobiology, and evolutionary psychology have succeeded in making the idea of "human nature" once again a commonplace of (...) public discourse, but the actual shape and content of human nature, even among Darwinian social scientists, remains controversial. Human nature is the product of evolution, and for Darwinians, concepts about the structure of human nature are necessarily bound up with concepts about the course of human evolution. My purpose in this essay will be to examine two chief alternatives in the current Darwinian understanding of human evolution and human nature, to advocate one of these alternatives, and to assess its implications for Darwinian literary study. One alternative can be identified with evolutionary psychology, and the other, the one I shall advocate, with evolutionary anthropology and cognitive archaeology. For the sake of economy, I shall refer to the former as the EP model and to the latter as the EACA model.In the late 1980s and early 1990s, the main theoretical controversy in Darwinian social science was that between the sociobiologists and Darwinian anthropologists, on the one side, and the evolutionary psychologists on the other. The point at issue was whether "fitness maximization" or the desire to maximize reproductive success could serve as a direct motive in human behavior. The sociobiologists tended to assume it could; the [End Page 33] evolutionary psychologists instead insisted that fitness maximization was mediated through "proximal mechanisms" such as the male desire for sex and the female desire to acquire resources from male sexual partners. In the arena of received professional opinion, the evolutionary psychologists won this debate, and evolutionary psychology is now the mainstream, establishment creed in Darwinian social science.2 Its hegemony is evidenced by a flood of popular expositions and textbooks. The majority of these expositions give little evidence that the authors are themselves alert to the speculative character of the fundamental concepts of their creed, and the chief tenets of the creed have often been reiterated in a naively uncritical way.The chief tenets of orthodox evolutionary psychology are (a) that the structure of the human mind stabilized during the Pleistocene (beginning about 1.6 million years ago); (b) that the human mind is "modular" in character—consisting of discrete bits of dedicated neural circuitry automatically activated by environmental releasers; (c) that human cognitive aptitudes and motivational structures are firmly adapted to the hunter-gatherer life-style of the Pleistocene—the "environment of evolutionary adaptedness" or EEA; and (d) that the adaptation to Pleistocene conditions carries with it, as a necessary corollary, a "mismatch" between the adapted human mind and all cultural ecologies more complex than that of hunter-gatherers. The core concept, the idea on which all the others depend, is that of the EEA:What we think of as all of human history—from, say, the rise of the Shang, Minoan, Egyptian, Indian, and Sumerian civilizations—and everything we take for granted as normal parts of life—agriculture, pastoralism, governments, police, sanitation, medical care, education, armies, transportation, and so on—are all the novel products of the last few thousand years. In contrast to this, our ancestors spent the last two million years as Pleistocene hunter-gatherers, and, of course, several hundred million years before that as one kind of forager or another. These relative spans are important because they establish which set of environments and conditions defined the adaptive problems the mind was shaped to cope with: Pleistocene conditions, rather than modern conditions.3For evolutionary psychologists, the difference between our Paleolithic ancestors and ourselves is a difference not in anatomical and neurological character but only in external "circumstances." In the EP model, the structure of the human mind at the present time and the structure [End Page 34] of the mind of, say, half a million years ago, would be the same. They would be equally the mind of the Pleistocene.The EP model of... (shrink)

The conditions of hunting and gathering through which one line of primates evolved into humans form the basis of what I term the wild self, a self marked by developmental needs of prolonged human neoteny and by deep attunement to the profusion of communicative signs of instinctive intelligence in which relatively “unmatured” hominids found themselves immersed. The passionate attunement to, and inquiry into, earth-drama, in tracking, hunting, foraging, rhythming, singing, and other arts/sciences, provided the trail to becoming human, and provide (...) external grammatical structures that became the basis of human language and animate mind. I outline my new philosophy of history as a progress in precision, counteracted by a regressive contraction of mind. The progress associated with history since the beginning of agriculturally-based civilizations can be considered as a regressive contraction from animate mind of our hunter-gatherer evolutionary past, to anthropocentric mind, and finally to the ghost in the machine world-view of mechanico-centric mind. Contemporary consumption culture represents an inversion of the original conditions of the human self, and indeed, targets aspects of developmental neoteny to condition conformity to its rational-mechanical system imperatives. (shrink)

Evolutionary theories of human cognition should refer to specific times in the primate or hominid past. Though alternative accounts of tool manufacture from Wynn's are possible (e.g., frontal lobe function), Wynn demonstrates the power of archaeology to guide cognitive theories. Many cognitive abilities evolved not in the “Pleistocene hunter-gatherer” context, but earlier, in the context of other patterns of social organization and foraging.

Extractive foraging tasks, such as digging, are broadly practiced among hunter-gatherer populations in different ecological conditions. Despite tuber-gathering tasks being widely practiced by children and adolescents, little research has focused on the physical traits associated with digging ability. Here, we assess how age and energetic expenditure affect the performance of this extractive task. Using an experimental approach, the energetic cost of digging to extract simulated tubers is evaluated in a sample of 40 urban children and adolescents of both sexes (...) to measure the intensity of the physical effort and the influence of several anatomical variables. Digging is a moderately vigorous activity for inexperienced girls and boys from 8 to 14 years old, and it requires significant physical effort depending on strength and body size. However, extracting subterranean resources is a task that may be performed effectively without previous training. Sex-specific and age-specific differences in the net energy expenditure of digging were detected, even though both sexes exhibited similar proficiency levels when performing the task. Our results highlight that both boys and girls spend considerable energy while digging, with differences largely driven by body size and age. Other factors beyond ability and experience, such as strength and body size, may influence the proficiency of juveniles in performing certain physically intensive foraging tasks, such as gathering tubers. (shrink)

History can be understood as involving a problematic interplay between the long-term legacy of human evolution, still tempered into the human body today, and the shorter-term heritage of civilization from its beginnings to the present. Each of us lives in a tension between our indigenous bodies and our civilized selves, between the philosophy of the earth and that which I characterize as “the philosophy of escape from the earth.” The standard story of civilization is one of linear upward progress, a (...) story that I contest with an alternative philosophy of history, picturing history instead as a set of concentric circles. I have devised a new philosophy of history with a three-part approach to understanding human development, taking civilization not as a linear advance of progress, but rather as a progress in precision, paradoxically counteracted by a regression in mind: history as a contraction of mind. I describe three stages in the contraction of mind: 1) animate mind as the evolved outlook of foraging life; 2) anthropocentric mind as representing the contracting transformation of consciousness produced by agriculturally-based civilization; 3) mechanico-centric mind as representing a further contraction from human-centered to a machine-centered consciousness, produced by the rise of modern civilization and the mechanical scientific worldview. Hence, this progressive contraction is marked by a turn from original practical and reverential attunement to the living earth in hunting and gathering societies, or animate mind, to a narrower focus of anthropocentric mind beginning with the development of early civilizations, where the human element became central and the wild devalued. And it moves to an even more narrow focus of mechanico-centric mind, expanding out of late medieval Europe and the development of modern science, where the machine became model of the ultimate, the objectivist filter through which the world is to be understood and made to fit. Far from controlling nature, humans have been consuming it in an unsustainable Malthusian-like trajectory whose limits are being reached in our time. (shrink)

This paper lays the groundwork for a theory of time allocation across the life course, based on the idea that strength and skill vary as a function of age, and that return rates for different activities vary as a function of the combination of strength and skills involved in performing those tasks. We apply the model to traditional human subsistence patterns. The model predicts that young children engage most heavily in low-strength/low-skill activities, middle-aged adults in high-strength/high-skill activities, and older adults (...) in low-strength/high-skill activities. Tests among Machiguenga and Piro forager-horticulturalists of southeastern Peru show that males and females focus on low-strength/low-skill tasks early in life (domestic tasks and several forms of fishing), switch to higher-strength/higher-skill activities in their twenties and thirties (hunting, fishing, and gardening for males; fishing and gardening for females), and shift focus to high-skill activities late in life (manufacture/repair, food processing). (shrink)

When we have asked Hadza whether married couples should live with the family of the wife (uxorilocally) or the family of the husband (virilocally), we are often told that young couples should spend the first years of a marriage living with the wife’s family, and then later, after a few children have been born, the couple has more freedom—they can continue to reside with the wife’s kin, or else they could join the husband’s kin, or perhaps live in a camp (...) where there are no close kin. In this paper, we address why shifts in kin coresidence patterns may arise in the later years of a marriage, after the birth of children. To do so, we model the inclusive fitness costs that wives might experience from leaving their own kin and joining their husband’s kin as a function of the number of children in their nuclear family. Our model suggests that such shifts should become less costly to wives as their families grow. This simple model may help explain some of the dynamics of postmarital residence among the Hadza and offer insight into the dynamics of multilocal residence, the most prevalent form of postmarital residence among foragers. (shrink)

We describe food transfer patterns among Ache Indians living on a permanent reservation. The social atmosphere at the reservation is characterized by a larger group size, a more predictable diet, and more privacy than the Ache typically experience in the forest while on temporary foraging treks. Although sharing patterns vary by resource type and package size, much of the food available at the reservation is given to members of just a few other families. We find significant positive correlations between amounts (...) transferred among pairs of families, a measure of the "contingency" component required of reciprocal altruism models. These preferred sharing partners are usually close kin. We explore implications of these results in light of predictions from current sharing models. (shrink)

This paper examines maternal trade-offs between subsistence/economic activities and caregiving, and it explores the effect of allomaternal investment on maternal time allocation and child care. I examine how nonmaternal investment in two multiple caregiving populations may offset possible risk factors associated with reductions in maternal caregiving. Behavioral observations were conducted on 8- to 12-month-old infants and their caregivers among the Aka tropical forest foragers and Ngandu farmers of Central Africa. Analysis demonstrates that mothers face trade-offs between subsistence/economic activities and (...) infant care. Infants receive less investment when their mothers engage in subsistence/economic activities, indicating a potential risk to those infants. However, results indicate that allomothers target their assistance during times when mothers are engaged in work activities, partially offsetting potential risks associated with the maternal trade-off. The effects of intercultural variability on maternal time allocation and allomaternal investment are also explored as a means of examining the potential impact of their behaviors on infant care. (shrink)

We welcome Tomasello’s new book on the natural history of human morality as an important confirmation of the evolutionary approach, which sees adaptive behaviors and their psychological underpinnings as linked to a species’ socioecology (the package of subsistence, social, mating, and rearing systems). This perspective automatically leads to the conclusion that the basic set of moral preferences is a straightforward human adaptation to the derived cooperative foraging niche of nomadic foragers, which involves a high degree of interdependence. We provide (...) more background information in support of this evolutionary approach, call for work on defining the contents of the innate core of moral preferences it implies, and urge philosophers to pursue its implications more seriously. Tomasello also offers a historical reconstruction, but his scenario is not compatible with recent comparative data showing a surprising overlap with aspects of human morality, nor does it fit the currently best-supported evolutionary scenario of hominin foraging. We offer a better-fitting alternative, but also call for more behavioral work in child development and on nonhuman primates to improve this reconstruction. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Philosophy and Literature 25.2 (2001) 233-250 [Access article in PDF] Narrative Theory and Function: Why Evolution Matters Michelle Scalise Sugiyama I It may seem a strange proposition that the study of human evolution is integral to the study of literature, yet that is exactly what this paper proposes. The reasons for this are twofold. Firstly, the practice of storytelling is ancient, pre-dating not only the advent of writing, but (...) of agriculture and permanent settlement as well. Secondly, narrative is ultimately a product of the mind, which in turn is the product of a long history of evolution by natural selection. Thus, an understanding of why and how humans create and consume narrative requires an understanding of (1) features of ancestral environments and (2) features of the mind that made the emergence of this phenomenon possible.There can be little doubt that narrative emerged in human prehistory. Language, an obvious prerequisite for storytelling, is likely to have emerged by at least 50,000 and possibly 250,000 years ago, depending upon whether one places one's trust in archaeological or anatomical evidence. 1 The most reasonable estimate is offered by Geoffrey Miller, who points out that, given its universality, the language faculty must have emerged by the time ancestral Homo sapiens began migrating out of Africa approximately 100,000 years ago. 2 Although the oldest known written narrative (The Epic of Gilgamesh) dates back only 5,000 years, the written literary traditions of many ancient cultures are known to be rooted in longstanding oral traditions. 3 The fact that many modern foraging peoples have rich and complex oral traditions further suggests that the emergence of narrative is not linked to the development of agriculture 10,000 years ago. Moreover, other forms of symbolic expression, such as the cave paintings, Venus figurines, and engraved bone [End Page 233] and antler that have been found at various sites throughout Europe, date back approximately 30,000 years, and rock paintings in Australia may date back even farther. 4 Since humans were physiologically capable of speech long before they began producing these artifacts, storytelling is likely to be at least as ancient as these other representational forms. Indeed, one scholar situates the "dawn of the oral tradition" within this period (Pfeiffer, p. 189). Given, then, that modern humans (Homo sapiens sapiens) have been in existence for approximately 100,000 years 5 and are the only hominid species or subspecies known for certain to exhibit storytelling behavior, we can safely say that oral narrative is a product of our hunting-and-gathering past, likely to have emerged between 30,000 and 100,000 years ago.The universality of narrative is further testimony to its being an ancient cognitive phenomenon. Literate or not, all known cultures, past and present, practice storytelling. 6 Moreover, all normally developing humans acquire the ability to process and generate stories: studies of Western children indicate that the ability to tell stories emerges spontaneously between the ages of two-and-a-half and three, and children as young as thirty months can distinguish between narrative and non-narrative uses of language. 7 In contrast to reading, writing, and arithmetic, no special education is required for narrative competence to develop, nor is there any evidence that oral literacy is acquired through contact with other cultures; although subject matter is often exchanged between groups, the practice of storytelling itself arises independently among even the most isolated peoples. Nor does any type of culture have a monopoly on narrative sophistication: the stories of hunter-horticulturalist societies are no less observant, insightful, or artful than those of agrarian or industrial societies.As with language, narrative takes the same basic form across cultures, which David Bordwell and Kristin Thompson define as "a chain of events in cause-effect relationship occurring in time." Given the preponderance of human agents in narrative, most narrative theorists would probably modify this barebones description to include character (usually understood to have a human psychology), goal-oriented action, and resolution. Frank Kermode, for example, defines the "proprieties" of narrative as "connexity, closure, and character," and John... (shrink)

Boehm's model conceptualizes a common ancestor to humans, chimpanzees, and bonobos at several million years B.P., followed by a model of prehistoric foragers at 25,000-50,000 B.P. based on ethnographic data from twentieth-century hunters and gatherers. By putting processes of complex communication into the picture, we can refine Boehm's model considerably by filling in significant scenarios for humans beginning at perhaps 2 million years ago. These include a suite of features that include constraints on sexual behaviour, a rudimentary division (...) of labour, the gendering of morality, socialized control over junior males, increased group size, increased home range size, the reduction of bullying behaviour, and a reverse dominance hierarchy that promotes egalitarianism among fully adult males. Boehm's model emphasizes the last two of these, but it is consistent with the others as well. Cultural or proto-cultural elaboration of beliefs and associated practices is the symbolic dimension of morality and is an important component of human evolution. Boehm's model is extremely important for outlining socio-political mechanisms and concomitants in the formation of adult male egalitarian groups, and, in the process, identifying a key element in the evolution of human morality. (shrink)