In the last 60,000 years humans have expanded across the globe and now occupy a wider range than any other terrestrial species. Our ability to successfully adapt to such a diverse range of habitats is often explained in terms of our cognitive ability. Humans have relatively bigger brains and more computing power than other animals and this allows us to figure out how to live in a wide range of environments. Here we argue that humans may be smarter than other (...) creatures, but none of us is nearly smart enough to acquire all of the information necessary to survive in any single habitat. In even the simplest foraging societies, people depend on a vast array of tools, detailed bodies of local knowledge, and complex social arrangements, and often do not understand why these tools, beliefs, and behaviors are adaptive. We owe our success to our uniquely-developed ability to learn from others. This capacity enables humans to gradually accumulate information across generations, and develop well-adapted tools, beliefs, and practices that are too complex for any single individual to invent during their lifetime. (shrink)

The human species is more reliant on cultural adaptation than any other species, but it is unclear how observational learning can give rise to the faithful transmission of cultural adaptations. One possibility is that teaching facilitates accurate social transmission by narrowing the range of inferences that learners make. However, there is wide disagreement about how to define teaching, and how to interpret the empirical evidence for teaching across cultures and species. In this article I argue that disputes about the nature (...) and prevalence of teaching across human societies and nonhuman animals are based on a number of deep-rooted theoretical differences between fields, as well as on important differences in how teaching is defined. To reconcile these disparate bodies of research, I review the three major approaches to the study of teaching – mentalistic, culture-based, and functionalist – and outline the research questions about teaching that each addresses. I then argue for a new, integrated framework that differentiates between teaching types according to the specific adaptive problems that each type solves, and apply this framework to restructure current empirical evidence on teaching in humans and nonhuman animals. This integrative framework generates novel insights, with broad implications for the study of the evolution of teaching, including the roles of cognitive constraints and cooperative dilemmas in how and when teaching evolves. Finally, I propose an explanation for why some types of teaching are uniquely human, and discuss new directions for research motivated by this framework. (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)

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)

Much existing literature in anthropology suggests that teaching is rare in non-Western societies, and that cultural transmission is mostly vertical (parent-to-offspring). However, applications of evolutionary theory to humans predict both teaching and non-vertical transmission of culturally learned skills, behaviors, and knowledge should be common cross-culturally. Here, we review this body of theory to derive predictions about when teaching and non-vertical transmission should be adaptive, and thus more likely to be observed empirically. Using three interviews conducted with rural Fijian populations, we (...) find that parents are more likely to teach than are other kin types, high-skill and highly valued domains are more likely to be taught, and oblique transmission is associated with high-skill domains, which are learned later in life. Finally, we conclude that the apparent conflict between theory and empirical evidence is due to a mismatch of theoretical hypotheses and empirical claims across disciplines, and we reconcile theory with the existing literature in light of our results. (shrink)

Although evidence of teaching behaviour has been identified in some nonhuman species, human teaching appears to be unique in terms of both the breadth of contexts within which it is observed, and in its responsiveness to needs of the learner. Similarly, cultural evolution is observable in other species, but human cultural evolution appears strikingly distinct. This has led to speculation that the evolutionary origins of these capacities may be causally linked. Here we provide an overview of contrasting perspectives on the (...) relationship between teaching and cultural evolution in humans, and briefly review previous research which suggests that cumulative culture can occur without teaching. We then report the results of a novel experimental study in which we investigated how the benefits of teaching may depend on the complexity of the skill to be acquired. Participants were asked to tie knots of varying complexity. In our Teaching condition, opportunities to interact with an experienced partner aided transmission of the most complex knots, but not simpler equivalents, relative to exposure to completed products alone, and also relative to information about the process of completion. We conclude by considering the plausibility of various accounts of the evolutionary relationship between teaching and cultural evolution in humans. (shrink)

The significance of teaching to the evolution of human culture is under debate. We contribute to the discussion by using a quantitative, cross-cultural comparative approach to investigate the role of teaching in the lives of children in two small-scale societies: Aka foragers and Ngandu farmers of the Central African Republic. Focal follows with behavior coding were used to record social learning experiences of children aged 4 to 16 during daily life. “Teaching” was coded based on a functional definition from evolutionary (...) biology. Frequencies, contexts, and subtypes of teaching as well as the identity of teachers were analyzed. Teaching was rare compared to observational learning, although both forms of social learning were negatively correlated with age. Children received teaching from a variety of individuals, and they also engaged in teaching. Several teaching types were observed, including instruction, negative feedback, and commands. Statistical differences in the distribution of teaching types and the identity of teachers corresponded with contrasting forager vs. farmer foundational cultural schema. For example, Aka children received less instruction, which empirically limits autonomous learning, and were as likely to receive instruction and negative feedback from other children as they were from adults. Commands, however, exhibited a different pattern suggesting a more complex role for this teaching type. Although consistent with claims that teaching is relatively rare in small-scale societies, this evidence supports the conclusion that teaching is a universal, early emerging cognitive ability in humans. However, culture structures the nature of teaching. (shrink)

Recent theoretical models suggest that the difference between human and nonhuman primate life-history patterns may be due to a reliance on complex foraging strategies requiring extensive learning. These models predict that children should reach adult levels of efficiency faster when foraging is cognitively simple. We test this prediction with data on Meriam fishing, spearfishing, and shellfishing efficiency. For fishing and spearfishing, which are cognitively difficult, we can find no significant amount of variability in return rates because of experiential factors correlated (...) with age. However, for shellfish collecting, which is relatively easy to learn, there are strong age-related effects on efficiency. Children reach adult efficiency more quickly in fishing as compared to shellfish collecting, probably owing to the size and strength constraints of the latter. (shrink)

This article introduces a new model of the relationship between growth and learning and tests a set of hypotheses related to the development of adult competency using time allocation, anthropometric, and experimental task performance data collected between 1992 and 1997 in a multiethnic community in the Okavango Delta, Botswana. Building on seminal work in life history theory by Hawkes, Blurton Jones and associates, and Kaplan and associates, the punctuated development model presented here incorporates the effects of both growth and learning (...) constraints on age-specific task performance. In addition, the payoff to investment in two forms of embodied capital, growth-based and learning-based, are examined in relation to features of the socioecology, including subsistence economy and family composition.The three main findings are:The development of adult competency in specific tasks entails a steplike relationship between growth- and experience-based forms of embodied capital in the ontogeny of ability acquisition.There is a trade-off between the acquisition of experience-based embodied capital in the form of skills and knowledge and immediate productivity among children. Time allocation to these alternatives is primarily determined by the short- and long-term costs and benefits to parents of investment in children’s embodied capital.The availability of laborers and the overall labor requirements of the household are major determinants of investment in alternate forms of embodied capital and resulting variation in children’s time allocation. The value of children’s labor to their parents is dependent upon the opportunity costs to engaging in other activities not only for the child in question but also for potential substitute laborers.These results have important implications for our understanding of the role of growth and learning in the evolution of the human juvenile period, as well as for our understanding of cross-cultural variation in child growth and development and patterns of work and play. (shrink)

Work-themed play may allow children to learn complex skills, and ethno-typical and gender-typical behaviors. Thus, play may have made important contributions to the evolution of childhood through the development of embodied capital. Using data from Aka foragers and Ngandu farmer children from the Central African Republic, we ask whether children perform ethno- and gender-typical play and work activities, and whether play prepares children for complex work. Focal follows of 50 Aka and 48 Ngandu children were conducted with the aim of (...) recording children’s participation in 12 categories of work and work-themed play. Using these data, we test a set of hypotheses regarding how age, gender, ethnicity, and task complexity influence children’s activities. As hypothesized, we find performance of work-themed play is negatively correlated with age. Contrary to our hypothesis, children do not play more than they work at complex tasks, but they work more than they play at simple ones. Gender and ethnicity are associated with play and work at culturally salient activities, despite availability of other-gender and other-ethnicity social partners. Our findings show that ethnic and gender biases are apparent in the play and work behavior of Aka and Ngandu children. Moreover, our results show that play helps both forager and farmer children learn complex skills, consistent with play having an adaptive learning function. (shrink)

Meriam children are active reef-flat collectors. We demonstrate that while foraging on the reef, children are significantly less selective than adults. This difference and the precise nature of children’s selectivity while reef-flat collecting are consistent with a hypothesis that both children and adults attempt to maximize their rate of return while foraging, but in so doing they face different constraints relative to differences in walking speeds while searching. Implications of these results for general arguments about factors that shape differences between (...) child and adult behavior and human life-histories are explored. (shrink)

Birth order has been examined over a wide variety of dimensions in the context of modern populations. A consistent message has been that it is better to be born first. The analysis of birth order in this paper is different in several ways from other investigations into birth order effects. First, we examine the effect of birth order in an egalitarian, small-scale, kin-based society, which has not been done before. Second, we use a different outcome measure, fertility, rather than outcome (...) measures of social, psychological, or economic success. We find, third, that being born late in an egalitarian, technologically simple society rather than being born early has a positive outcome on fertility, and fourth, that number of older siblings and sibling set size are even stronger predictors of fertility, especially for males. (shrink)

The Hadza foragers of Tanzania are currently experiencing a nutritional shift that includes the intensification of domesticated cultigens in the diet. Despite these changes, no study, to date, has examined the possible effects of this transition on the food collection behavior of young foragers. Here we present a cross-sectional study on foraging behavior taken from two time points, 2005 and 2017. We compare the number of days foraged and the type and amount of food collected for young foragers, aged 5–14 (...) years, in age- and season-matched samples. Compared with 2005, in 2017 fewer subadults left camp to forage, and overall, they targeted a smaller variety of wild foods, with the noticeable absence of wild honey, figs, and tubers. In addition, participants in 2017 were significantly more likely to have attended school. Despite the increased presence of domesticated plant foods in the diet and increased attendance at school, some young foragers continue to be highly productive in collecting wild, undomesticated foods. Despite the preliminary nature of our results, our findings suggest that the range of wild foods targeted by subadults is decreasing as the amount of domesticated cultigens in the diet increases. These data underscore the importance of studying diet composition and foraging decisions across temporal, nutritional, and ecological landscapes. (shrink)

This paper examines how innovative skills and knowledge are transmitted and acquired among adolescents in two hunter-gatherer communities, the Aka of southern Central African Republic and the Chabu of southwestern Ethiopia. Modes of transmission and processes of social learning are addressed. Innovation as well as social learning have been hypothesized to be key features of human cumulative culture, enhancing the fitness and survival of individuals in diverse environments. The innovation literature indicates adult males are more innovative than children and female (...) adults and therefore predicts that adolescents will seek out adult males. Further, the mode of transmission should be oblique. Thus, learning of innovations should be oblique or horizontal rather than vertical, with adolescents paying particular attention to “successful” innovative individuals. The social learning literature indicates that complex skills or knowledge is likely to be learned through teaching, and therefore that teaching will be an important process in the transmission of innovations. In-depth and semi-structured interviews, informal observations, and systematic free-listing were used to evaluate these hypotheses. The study found that cultural context patterned whether or not adolescents sought out adult male or female innovators; oblique modes of transmission were mentioned with greater frequency than horizontal or vertical modes; knowledge and skill bias was notable and explicitly linked by the adolescents to reproductive effort; and teaching was biased toward same-sex individuals and was an important but not an exclusive means of transmitting complex skills and social knowledge. (shrink)