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)

In this chapter, I argue that the field of cultural evolution can usefully inform attempts to understand and influence the long-term future. First, I provide an overview of cultural evolution, covering what it means for culture to evolve, the mechanisms by which it happens, the crucial importance of cumulative cultural evolution for hunan history, and how cultural evolution (and in particular intergroup competition) has driven the rise of large-scale cooperation. Second, I draw out some possible lessons from cultural evolution for (...) thinking about the long-term future. In particular, I suggest we should be careful not to prematurely ”lock in” certain values or other cultural features, and instead aim for a society open to variation and competition. I also consider whether the future will bring greater selection pressure for particular kinds of values, such as patience. (shrink)

This article argues that understanding human uniqueness requires recognizing that we are a cultural species whose evolution has been driven by the interaction among genes and culture for over a million years. Here, I review the basic argument, incorporate recent findings, and highlight ongoing efforts to apply this approach to more deeply understand both the universal aspects of our cognition as well as the variation across societies. This article will cover (1) the origins and evolution of our capacities for culture, (...) (2) examples of specialized mental abilities such as those related to mechanical causality, prestige, and cooperation, and (3) recent efforts to apprehend our capacities for abstraction. I close by discussing common canards that generate confusion in mapping what makes us human. (shrink)

When people get ill, they naturally want to restore health through medical interventions. Here I model a situation in which individuals can psychologically entertain multiple potential treatments at once: when illness occurs, individuals would attempt one treatment first, and if it fails to produce an observable effect within a particular time period, a second treatment is attempted, and the eventual recovery is attributed to the treatment that is temporally closer. This creates population dynamics wherein the therapeutic power of the superior/effective (...) medical treatments is misattributed to inferior/ineffective treatments. Through both analytic formulation and agent-based simulation, I show that the equilibrium frequencies of different treatment variants depend on their natural variability in the effect timing, the level of individual patience, and the number of cultural models sampled by the naive individual. Both ineffective and effective medical treatments may stably coexist in the population under a range of parameter settings. (shrink)

This research provides evidence regarding the causal effect of group conformity on task performance in stable and variable environments. Drawing on studies in cultural evolution, social learning, and social psychology, we experimentally tested the hypotheses that conformity improves group performance in a stable environment (H1) and decreases performance (by hindering adaptability) in a temporally variable environment (H2). We compare the performance of individuals, low conformity groups, and high conformity groups in a four-arm randomized lab experiment (N = 240). High conformity (...) was manipulated by rewarding agreement with the group’s majority and imposing a cost on disagreement. The monetary implications of conformity impaired performance in a variable environment but did not have a significant effect on performance in the stable environment. Intragroup individual-level analyses provide insights into the mechanisms that account for the group-level results by showing that lower conformity in groups facilitates efficient adaptability in the use of social information. (shrink)

Prior work has demonstrated that young children in the US and the Ecuadorian Amazon preferentially remember information about the dangerousness of an animal over both its name and its diet. Here we explore if this bias is present among older children and adults in Fiji through the use of an experimental learning task. We find that a content bias favoring the preferential retention of danger and toxicity information continues to operate in older children, but that the magnitude of the bias (...) diminishes with age and is absent in adults. We also find evidence that fitness costs likely impact the types of mistakes that participants make in their attributions of dangerousness and poisonousness. These results suggest that natural selection has shaped the way in which we learn and make inferences about unfamiliar animal species over ontogeny, and that future research is needed on how content biases may vary across the life course. (shrink)

Most research on transmission biases in cultural evolution has treated different biases as distinct strategies. Here I present a model that combines both frequency dependent bias (including conformist bias) and payoff bias in a single decision-making calculus and show that such an integrated learning strategy may be superior to relying on either bias alone. Natural selection may operate on humans’ relative dependence on frequency and payoff information, but both are likely to contribute to the spread of variants with high payoffs. (...) Importantly, the magnitude of conformist bias affects the evolutionary dynamics, and I show that an intermediate level of conformity may be most adaptive and may spontaneously evolve as it resists the invasion of low-payoff variants yet enables the fixation of high-payoff variants in the population. (shrink)