Title: The role of causal knowledge in the evolution of traditional technology
Abstract: Humans occupy a wider range of environments, process more energy, and have greater biomass than any other species because we are able to culturally evolve complex, locally adaptive technologies.1Henrich J. The secret of our success: How culture is driving human evolution, domesticating our species, and making us smarter. Princeton University Press, 2017Google Scholar Competing models make different predictions about the role of causal knowledge in this process. Some argue that innovation and transmission cannot occur without causal understanding,2Tooby J. DeVore I. The Reconstruction of Hominid Evolution Through Strategic Modeling.in: Kinzey E.G. The Evolution of Human Behavior: Primate Models. SUNY Press, 1987: 183-237Google Scholar, 3Pinker S. Colloquium paper: the cognitive niche: coevolution of intelligence, sociality, and language.Proc. Natl. Acad. Sci. USA. 2010; 107: 8993-8999Crossref PubMed Scopus (235) Google Scholar, 4Osiurak F. Reynaud E. The elephant in the room: What matters cognitively in cumulative technological culture.Behav. Brain Sci. 2019; 43: e156Crossref PubMed Scopus (43) Google Scholar, 5Osiurak F. Cretel C. Duhau-Marmon N. Fournier I. Marignier L. De Oliveira E. Navarro J. Reynaud E. The Pedagogue, the Engineer, and the Friend : From Whom Do We Learn?.Hum. Nat. 2021; : 1-21PubMed Google Scholar while others posit that complex technologies can evolve without causal understanding.1Henrich J. The secret of our success: How culture is driving human evolution, domesticating our species, and making us smarter. Princeton University Press, 2017Google Scholar,6Boyd R. Richerson P.J. Henrich J. The cultural niche: why social learning is essential for human adaptation.Proc. Natl. Acad. Sci. USA. 2011; 108: 10918-10925Crossref PubMed Scopus (541) Google Scholar, 7Boyd R. Richerson P.J. Henrich J. The cultural evolution of technology: facts and theories.Cultural evolution: society, technology, language, and religion. 2013; 12: 119-142Crossref Google Scholar, 8Heyes C. New thinking: the evolution of human cognition. The Royal Society, 2012Google Scholar, 9Richerson P.J. Boyd R. Not by genes alone: how culture transformed human evolution. University of Chicago Press, 2005Google Scholar, 10Boyd R. A different kind of animal: How culture transformed our species.Volume 46. Princeton University Press, 2017Crossref Google Scholar Prior research on this topic has been restricted to theoretical work and experimental studies with student participants.11Derex M. Bonnefon J.-F. Boyd R. Mesoudi A. Causal understanding is not necessary for the improvement of culturally evolving technology.Nat. Hum. Behav. 2019; 3: 446-452Crossref PubMed Scopus (37) Google Scholar, 12Morgan T.J.H. Testing the Cognitive and Cultural Niche Theories of Human Evolution.Curr. Anthropol. 2016; 57: 370-377Crossref Scopus (18) Google Scholar, 13Derex M. Boyd R. The foundations of the human cultural niche.Nat. Commun. 2015; 6: 8398Crossref PubMed Scopus (55) Google Scholar The Hadza are foragers who rely on bows for subsistence.14Marlowe F. The Hadza: hunter-gatherers of Tanzania.Volume 3. University of California Press, 2010Crossref Google Scholar, 15Pontzer H. Raichlen D.A. Basdeo T. Harris J.A. Mabulla A.Z.P. Wood B.M. Mechanics of archery among Hadza hunter-gatherers.Journal of Archaeological Science: Reports. 2017; 16: 57-64Crossref Scopus (7) Google Scholar, 16Woodburn J. Hunters and Gatherers: the Material Culture of the Nomadic Hadza. British Museum, 1970Google Scholar We interviewed skilled Hadza bowyers (bow-makers) and compared their beliefs regarding the tradeoffs in bow construction to those revealed by experimental and engineering research. If bowyers understand the tradeoffs, it is plausible that cultural evolution is rooted in causal understanding, while if they do not, the cultural accumulation of knowledge is likely more important in the process. We show that Hadza bowyers understand some mechanical trade-offs but not others, and therefore the evolution of a complex, highly adaptive technology is possible with incomplete causal knowledge regarding key mechanical trade-offs. Instead, some important design choices made by subjects seem to reflect cultural norms. Although previously published reports have suggested that some individuals are recognized by the Hadza as being especially skilled or knowledgeable,14Marlowe F. The Hadza: hunter-gatherers of Tanzania.Volume 3. University of California Press, 2010Crossref Google Scholar,17Blurton Jones N. Demography and evolutionary ecology of Hadza hunter-gatherers.Volume 71. Cambridge University Press, 2016Crossref Scopus (38) Google Scholar our results do not indicate that some individuals are significantly more knowledgeable about bow-making than others, nor is there statistical evidence that causal knowledge increases with age.