The life history of human foraging: Cross-cultural and individual variation

Science Advances • Vol/Iss. 6(26) • American Association for the Advancement of Science • • Published In • Pages: 1-7 •
By Koster, Jeremy M., McElreath, Richard L., Hill, Kim, Yu, Douglas, Shepard, Glenn, van Vliet, Nathalie, Gurven, Michael, Trumble, Benjamin, Bird, Rebecca Bliege, Bird, Douglas, Codding, Brian, Coad, Lauren, Pacheco-Cobos, Luis, Winterhalder, Bruce, Lupo, Karen, Schmitt, Dave, Sillitoe, Paul, Franzen, Margaret, Alvard, Michael, Venkataraman, Vivek, Kraft, Thomas, Endicott, Kirk, Beckerman, Stephen, Marks, Stuart A., Headland, Thomas, Pangau-Adam, Margaretha, Siren, Anders, Kramer, Karen L., Greaves, Russell D., Reyes-García, Victoria, Guèze, Maximilien, Duda, Romain, Fernández-Llamazares, Álvaro, Gallois, Sandrine, Napitupulu, Lucentezza, Ellen, Roy, Ziker, John, Nielsen, Martin R., Ready, Elspeth, Healey, Christopher, Ross, Cody T.

Abstract

In this article researchers created a model to answer the question "What is a typical human life history of foraging skill?" While the immediate goal of this study was to create a model focused on age and relative skill, the larger purpose was to draw more clarity around the trajectory of human foraging skill over time. Researchers used data on hunting returns from 40 different study sites from around the world (Table 1) in order to assess the success of an expedition. While the model created here does not draw conclusions as to the absolute levels of production within or between societies, it can inform cross-cultural comparisons of relative skill at different stages of life. In conclusion, researchers found that the average hunter peaks at 33 years old, and by age 18, has 89% maximum skill (with the range of maximum skill being from ages 24-25). This skill was also found to decline slowly, such that it falls below 89% maximum after age 56. In terms of cross-cultural findings, the model found that cross-cultural variation is evident in the rate at which hunters develop peak skill, (meaning that within sites, the rate at which hunters develop skill is relatively homogeneous compared to the variation that distinguishes young hunters in different study sites), and individual hunters develop physical and cognitive abilities in concert, resulting in high hunting success by their late 20s and early 30s. In order to run the model, this study used the Hamiltonian Monte Carlo algorithm (in the Rstan package) for the sampling, and a Cobb-Douglas production function to express the observable foraging returns.

Note

Due to the nature of the Bayesian framework, the statistical findings are not reported below. Instead, we recommend looking directly at the article and the corresponding supplements for in-depth model descriptions and coding.

Samples

Sample Used Coded Data Comment
23,747 observations of 1,821 individual foragers across 40 study sites Researcher's Own
Documents and Hypotheses Filed By: matthew.g.roth  abbe.mccarter