On the absence of a correlation between population size and ‘toolkit size' in ethnographic hunter–gatherers

• Published in: Philosophical transactions of the Royal Society of London. Series B. Biological sciences Vol. 373; no. 1743; p. 20170061
• Main Author: Aoki, Kenichi
• Format: Journal Article
• Language: English
• Published: England The Royal Society 05.04.2018; The Royal Society Publishing
• Subjects: Anthropology, Cultural; Cultural Evolution; Empirical analysis; Ethnographic Observable; Ethnography; Humans; Interdisciplinary studies; Life Style; Mathematical models; Mode Of Cultural Transmission; Models, Biological; Opinion Piece; Population; Population (statistical); Population Density; Population number; Statistical analysis; Theoretical Variable; Variable Population Size; ethnographic observable; theoretical variable; mode of cultural transmission; variable population size
• ISSN: 0962-8436; 1471-2970
• DOI: 10.1098/rstb.2017.0061

In apparent contradiction to the theoretically predicted effect of population size on the quality/quantity of material culture, statistical analyses on ethnographic hunter–gatherers have shown an absence of correlation between population size and toolkit size. This has sparked a heated, if sometimes tangential, debate as to the usefulness of the theoretical models and as to what modes of cultural transmission humans are capable of and hunter–gatherers rely on. I review the directly relevant theoretical literature and argue that much of the confusion is caused by a mismatch between the theoretical variable and the empirical observable. I then confirm that a model incorporating the appropriate variable does predict a positive association between population size and toolkit size for random oblique, vertical, best-of-K, conformist, anticonformist, success bias and one-to-many cultural transmission, with the caveat that for all populations sampled, the population size has remained constant and toolkit size has reached the equilibrium for this population size. Finally, I suggest three theoretical scenarios, two of them involving variable population size, that would attenuate or eliminate this association and hence help to explain the empirical absence of correlation. This article is part of the theme issue ‘Bridging cultural gaps: interdisciplinary studies in human cultural evolution'.