Testing the theory that human's long developmental period is due to difficulty in learning complex foraging skills

Testing the theory that human’s long developmental period is due to difficulty in learning complex foraging skills
Foraging returns. (A) Predicted change in foraging returns with age, averaging over variation between studies, individuals, sex, and resource type. The x axis shows age, while the y axis is a unit-free measure of the proportion of increase compared to the maximum value (predicted returns at age 20). Solid line is the posterior median prediction; shaded intervals depict the 30th, 60th, and 90th percentile credible intervals. Dashed lines highlight arbitrary age differentials across childhood. (B) Predicted change in foraging returns by resource type, with thick lines denoting the average posterior median and thin lines denoting the median for each unique study outcome for that resource type. All curves are scaled by their maximum value (predicted returns at age 20). The shape of the curves illustrates how productivity increases with age. (C) Percentage increase in foraging returns across childhood, covering the intervals denoted by the dashed lines in (A) and (B). Points indicate posterior median, and bars indicate 90% HPDI (Highest Posterior Density Interval). Credit: Science Advances (2022). DOI: 10.1126/sciadv.abn9889

Ilaria Pretelli and Sheina Lew-Levy from the Max Planck Institute for Evolutionary Anthropology and Erik Ringen from Emory University report evidence to support a theory that the reason human beings have such a long developmental period is that it takes a long time to learn complex foraging skills. The study is published in the journal Science Advances.

Scientists have long puzzled over the reason for the long human developmental period—it can take nearly two decades for humans to fully mature. Some researchers have suggested it is merely a byproduct of a long lifespan, while others have suggested it is more likely due to the steep learning curve involved in becoming proficient at foraging. In this new effort, the researchers suspected it was the latter and sought supporting evidence in past studies that focused on modern groups of people that still rely on foraging.

The groups studied by the researchers included Inuit, Cree, the Hadza and Martu. As part of their study, they first categorized the degree of difficulty in foraging based on the type of foraging done by the groups under study. It takes little time to learn how to identify and pick berries, for example, while many years are needed to learn how to hunt with a bow and arrow. They also noted that the types of have different physical requirements. Digging for tubers, for example, requires a lot more effort than pulling fruit from a tree, though the latter may also require more height.

The differences between the groups showed that were quickly able to learn to do easier tasks, while other more sometimes took many years to master. The researchers suggest that long childhoods evolved to meet these variable challenges, particularly those that took a long time to master.

More information: Ilaria Pretelli et al, Foraging complexity and the evolution of childhood, Science Advances (2022). DOI: 10.1126/sciadv.abn9889

Journal information: Science Advances

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Citation: Testing the theory that human's long developmental period is due to difficulty in learning complex foraging skills (2022, October 13) retrieved 29 March 2024 from https://phys.org/news/2022-10-theory-human-developmental-period-due.html
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