Lew-Levy and Amir’s paper presents a compelling argument for recognizing peer cultures as central to cultural evolution. They demonstrate that children do not merely acquire adult knowledge but actively produce, refine, and transmit cultural elements within peer groups. Our recent field data with hunter–gatherers and pastoralists support several of their claims. For example, in 160 hours of observation among transitional hunter–gatherers and pastoralists, we found that child-to-child teaching was common, occurring in 42% of learning events. While our findings align with some of Lew-Levy and Amir’s insights, our commentary focuses on two aspects of peer culture that help explain cultural evolutionary issues raised in the paper: concerted and cumulative group-based modes of transmission that may contribute to the stability of peer culture and culturally constructed niches that shape the diversity and evolution of peer cultures. We draw on field data from Koygu transitional hunter–gatherers, Nyangatom pastoralists in Ethiopia, and Aka hunter–gatherers in the Central African Republic.

The authors note the relatively stable nature of peer cultures but do not elaborate on the mechanisms maintaining this stability. We hypothesize that two modes of group transmission – concerted and cumulative – may contribute to peer culture stability over time (Hewlett et al., Reference Hewlett, Boyette, Lew-Levy, Gallois and Dira2024). Concerted transmission occurs when multiple group members communicate the same skill or knowledge to an individual (Cavalli-Sforza et al., Reference Cavalli-Sforza, Feldman, Chen and Dornbusch1982). This mode, observed in 38% of 494 learning events among the Koygu and Nyangatom, fosters group homogeneity and trait conservation and reduces rates of culture change. Notably, 45.5% of these concerted transmission events occurred in child-only groups, with an average of 3.7 children per event – more than in mixed adult-child groups (3.1).

It may be useful to provide examples of concerted transmission. Among the Aka, an entire group of children will make sounds of disgust if a child takes more than their share of food, does not share food, or hits another child. Spear hunting for mice is a child-only activity among the Aka, and it is common for multiple children to comment on how to throw the spear, where the mouse is, or how to divide it with others.

Another example from the Koygu involves a mixed-age group of boys (6–15) swimming in the Omo River. When the youngest hesitated to swim, an older boy invited him in and offered help. After some teasing from the group, the younger child agreed to try. The older boy reassured him, offering his hand in the water and instructing him to move his hands and legs. Another child demonstrated the motions, guiding the younger boy’s leg, while the rest encouraged his efforts.

Another mode of group transmission we want to consider is cumulative transmission. This mode refers to specific knowledge or skills individuals acquire from repeated multimodal experiences and interactions with several group members with those skills or knowledge (Hewlett et al., Reference Hewlett, Boyette, Lew-Levy, Gallois and Dira2024). It is cumulative because the transmission builds upon the child’s previous lived experiences; i.e., it involves scaffolding of abilities. It tends to contribute to group homogeneity and trait stability over time.

For instance, the Aka are net hunters, and children participate with other children on net hunts. They make nets together, pick up nets sitting around camp, and try to trap chickens together; they joke about children who made mistakes on the hunt (chasing game animals in the wrong direction) and listen to imaginative stories about net hunting from older children.

Similarly, among the Nyangatom, cumulative cultural transmission is evident in herding games. Young children often played herding games together, building miniature kraals and placing small stones inside to represent cattle. They also followed older boys to herding fields and, by 8–10 years old, began herding goats themselves.

While Lew-Levy and Amir describe peer cultures across societies, they do not explore how cultural niche construction influences the diversity and evolution of peer cultures. For example, child teaching occurred in 52.4% of learning events among the Koygu but only 35.3% among the Nyangatom. Similarly, concerted transmission was more frequent among the Koygu (57.9%) than the Nyangatom (32.9%). Koygu child-only concerted transmission events involved an average of 4.5 children, compared to 3.6 among the Nyangatom.

Culturally constructed niches (Laland et al., Reference Laland, Odling-Smee and Feldman2001) can help explain some of the observed variability in peer cultures. Foundational schema (ways of thinking and feeling that pervade several domains of life: Shore, Reference Shore1996), social structures, settlement patterns, and proxemics are part of these niches to which children have to adapt. Among the Nyangatom, generational hierarchy is a dominant schema: respect for elders, especially male elders, governs much of social life (Tornay, Reference Tornay and Bender1981; Bedasso, Reference Bedasso2016). These ways of thinking and structures contribute to hierarchical teaching from adults. In contrast, the egalitarian nature of the Koygu provides individuals autonomy to navigate their environment with others. Constraints do not exist for children teaching children, and adults minimize their interventions in children’s learning.

Settlement patterns also affect adaptations and evolution in peer cultures. The Koygu live in large, densely populated villages (some over 100 households with houses only a few feet apart), partly due to inter-ethnic conflict and the need for security (Turton, Reference Turton, Donham and James1986). This proximity creates ample opportunities for peer interaction and learning. The Nyangatom, while more populous overall, live in smaller, more dispersed villages – some larger villages have 10–15 households, others as small as 1–5. These spatial arrangements limit the size and frequency of peer group interactions.

Koygu egalitarianism and dense social living help explain why both child-only concerted transmission and child teaching are more frequent than among the Nyangatom. The contrast between the egalitarian, densely populated Koygu villages and more hierarchical, dispersed Nyangatom settlements illustrates how these niches create divergent developmental ecologies that shape peer culture and cultural evolution.

Lew-Levy and Amir provide a foundation for understanding the central role of peer cultures in cultural evolution. Our data from the Koygu, Nyangatom, and Aka communities complement and build upon their insights by identifying two forms of transmission that contribute to the stability of peer cultures over time (concerted and cumulative transmission) and describing how culturally constructed niches contribute to the diversity of peer cultures.