Technological complexity and the nature of adaptive problem-solving in small-scale societies

<p>Technological complexity is a defining eature of human adaptation, yet the processes determining how much technology societies require remain poorly understood. Existing explanations emphasize environmental risk, resource productivity, or demographic factors, but provide limited insight into why technological systems respond differently across subsistence economies. Here, we propose that technological complexity reflects the computational burden imposed by environmental uncertainty. In seasonal environments, survival requires solving a sequential decision problem in which risks accumulate multiplicatively across the year, increasing demand for technological buffering. Technologies reduce this uncertainty but are costly to produce and maintain, generating an optimization problem balancing risk reduction against technological costs. We further argue that niche construction fundamentally alters this relationship by smoothing environmental variability and transforming exogenous uncertainty into managed, endogenous processes. From this framework we derive the prediction that technological complexity should increase with environmental seasonality among hunter-gatherers but become increasingly independent of climate as niche construction intensifies. We test these predictions using data on toolkit richness and component-part diversity from 127 small-scale societies. We find the richness of hunter-gatherer technologies increases exponentially with environmental seasonality, whereas farming technologies remain largely invariant across climatic regimes. These findings suggest that technological complexity responds to the informational and computational demands environmental conditions impose. More broadly, these results imply that agriculture represents not simply a new mode of energy acquisition, but a transition in the computational architecture of human adaptation, in which farming reduces the effective depth of adaptive problems by restructuring the environments that generate uncertainty.</p>