Cultural transmission among hunter-gatherers

Abstract

We examine from whom children learn in mobile hunter-gatherers, a way of life that characterized much of human history. Recent studies on the modes of transmission in hunter-gatherers are reviewed before presenting an analysis of five modes of transmission described by Cavalli-Sforza and Feldman [L. L. Cavalli-Sforza, M. W. Feldman, Cultural Transmission and Evolution: A Quantitative Approach (1981)] but not previously evaluated in hunter-gatherer research. We also present two modes of group transmission, conformist transmission, and concerted transmission, seldom mentioned in hunter-gatherer social learning research, and propose a unique mode of group transmission called cumulative transmission. The analysis of the additional modes of transmission indicated that cultural evolutionary signatures of vertical transmission, such as the conservation of cultural traits, have been underestimated because previous studies have seldom considered remote generations or distinguished intrafamilial from extrafamilial horizontal and oblique transmission. However, field data also indicate that hunter-gatherer children interacted with and learned from many nongenetically related individuals; about half of children's and adolescents' horizontal and oblique social learning came from nongenetically related individuals. Intimate living conditions of hunter-gatherers provide opportunities for group transmission, and ethnographic evidence presented demonstrates that at least three types of group transmission exist. All three forms of group transmission theoretically contribute to the conservation of culture, homogeneity of intracultural diversity, and high intercultural diversity. Analysis of additional modes of oblique and horizontal transmission and discussion of previous and unique modes of group transmission demonstrate the various mechanisms by which hunter-gatherer children learn and how cultures are conserved and contribute to cumulative culture.

Keywords: child development; cultural transmission; hunter-gatherers; social learning.

Fig. 1.

Contrasts between older and younger Aka children in relative probability of learning via each mode. This figure shows the difference in the distribution of Bayesian posterior probability density estimates of Aka children of ages in the middle-childhood and adolescent developmental niches, given the relative frequency of encounters with these social partners. Estimated contrasts below zero indicate more learning by younger children via that mode, and estimated contrasts above zero indicate more learning by older children via that mode. The degree to which the probability density estimates exclude zero indicates the relatively greater likelihood that there is a true difference between older and younger children in the probability of learning via that mode (equivalent to a “significant” difference in frequentist statistics). The distance from zero of the probability density estimates reflects the relative effect size of the contrast between younger and older children. The interior lines within the density estimates show the 0.11 and 0.89 quantiles (50).

Fig. 2.

Three modes of group transmission. The two-way arrows in conformist transmission refer to an adaptive strategy where the juvenile looks at all adults (large images) and juveniles (smaller images) in the group and copies the most common trait (individuals in blue). The solid arrows in concerted transmission refer to adults and juveniles teaching cultural skills or knowledge that they feel are important to transmit to the juvenile. Compliance of individuals is expected. The two-way arrows in cumulative transmission refer to the self-motivated juvenile watching, listening, and interacting with many adults with a trait and modifying the trait with more encounters. The solid arrows refer to direct teaching of traits by adults and juveniles. The teaching may be spontaneous or concerted.