The Dawn of Everything: A New History of Humanity

by David Graeber

Optimal foraging theory is a style of predictive modelling that originates in the study of non-human species such as starlings, honeybees or fish. Applied to humans, it typically frames behaviour in terms of economic rationality, i.e.: ‘foragers will design their hunting and collecting strategies with the intention of obtaining a maximum return in calories, for a minimum outlay of labour.’ This is what behavioural ecologists call a ‘cost-benefit’ calculation. First you figure out how foragers ought to act, if they are trying to be as efficient as possible. Then you examine how they do in fact act. If it doesn’t correspond to the optimum foraging strategy, something else must be going on. From this perspective, the behaviour of indigenous Californians was far from optimal. As we’ve noted, they relied primarily on gathering acorns and pine nuts as staples. In a region as bounteous as California, there’s no obvious reason to do this. Acorns and pine nuts offer tiny individual food packages and require a great deal of labour to process. To render them edible, most varieties require the back-breaking work of leaching and grinding to be carried out, to remove toxins and release nutrients. Nut yields can vary dramatically from one season to the next, a risky pattern of boom and bust. At the same time, fish are found in abundance from the Pacific Coast inland at least as far as the confluence of the Sacramento and San Joaquin Rivers. Fish are both more nutritious and more reliable...