Costly teaching contributes to the acquisition of spear hunting skill among BaYaka forager adolescents

Abstract

Teaching likely evolved in humans to facilitate the faithful transmission of complex tasks. As the oldest evidenced hunting technology, spear hunting requires acquiring several complex physical and cognitive competencies. In this study, we used observational and interview data collected among BaYaka foragers (Republic of the Congo) to test the predictions that costlier teaching types would be observed at a greater frequency than less costly teaching in the domain of spear hunting and that teachers would calibrate their teaching to pupil skill level. To observe naturalistic teaching during spear hunting, we invited teacher–pupil groupings to spear hunt while wearing GoPro cameras. We analysed 68 h of footage totalling 519 teaching episodes. Most observed teaching events were costly. Direct instruction was the most frequently observed teaching type. Older pupils received less teaching and more opportunities to lead the spear hunt than their younger counterparts. Teachers did not appear to adjust their teaching to pupil experience, potentially because age was a more easily accessible heuristic for pupil skill than experience. Our study shows that costly teaching is frequently used to transmit complex tasks and that instruction may play a privileged role in the transmission of spear hunting knowledge.

The cultural evolution of teaching

“…BaYaka caregivers use pointing, eye contact and child-directed speech to direct a child or infant's attention and to familiarise them with tools through negative feedback, demonstrations and opportunity scaffolding (providing the infant with an object to explore) (Hewlett & Roulette, 2016 ; Boyette & Hewlett, 2017 ). When hunter–gatherers and mixed subsistence societies use costly forms of teaching such as abstract verbal communication, this is usually done to communicate opaque knowledge such as social norms (Salali et al, 2019 ) and complex skills such as spear hunting (Lew-Levy et al, 2022 ). However, in many cases explanations of plant and animal knowledge still occur alongside hands-on practice and opportunity scaffolding (MacDonald, 2007 ; Lew-Levy et al, 2022 ).…”

“…When hunter–gatherers and mixed subsistence societies use costly forms of teaching such as abstract verbal communication, this is usually done to communicate opaque knowledge such as social norms (Salali et al, 2019 ) and complex skills such as spear hunting (Lew-Levy et al, 2022 ). However, in many cases explanations of plant and animal knowledge still occur alongside hands-on practice and opportunity scaffolding (MacDonald, 2007 ; Lew-Levy et al, 2022 ).…”

Atlatl use equalizes female and male projectile weapon velocity

“…One proposed hypothesis for the adoption of the atlatl and dart over the thrown javelin is that the former acted as an “equalizer”, thereby facilitating the participation of more people in a hunt, and reducing social disparity 27 , 30 , 31 . Researchers have proposed that the effective use of javelins would have required strength, a potentially larger body size, and high investment in training 23 , 32 . If the atlatl and dart render body size, strength, or training time less important to hunting success, then more, or different, people could partake in the hunt which would allow a greater number of tactical options, increase the chances of hitting the animal target, and reduce the onus of hunting success on a small number of individuals possessing a particular set of physical attributes.…”

Despite COVID: showcasing new research in evolutionary biology from academic care-givers in the middle of a pandemic

“…Traditionally the focus of male-male interactions has been on competition, but Saldaña-Sánchez et al [27] show that male spider monkeys' behaviour is influenced by some socio-ecological factors, such as food availability and proximity to the home range boundary, but not others, such as the presence of receptive females, suggesting ways that males in this male-philopatric, fission-fusion society can flexibly adjust their relationships to allow for both cooperation and competition. Lew-Levy et al [28] found that information transmission about spear hunting in BaYaka foragers occurred through costly teaching, typically direct instruction, which differs from other domains in which learning occurs through lower-cost mechanisms. McCullagh et al [29] studied the development of the auditory brainstem in naked mole rats, which diverge from other rodents in many physiological aspects owing to their highly specialized underground lifestyle; they show that despite this divergence, they have similar hearing onset as other rodents, although they show developmental differences in other respects.…”

“…Lew-Levy et al . [28] found that information transmission about spear hunting in BaYaka foragers occurred through costly teaching, typically direct instruction, which differs from other domains in which learning occurs through lower-cost mechanisms. McCullagh et al .…”