Risk and toolkit structure in the Pacific Northwest

Identifying the factors that drive the variation in technological complexity among traditional societies is important for understanding human evolution. With respect to hunter-gatherers, the leading hypothesis focuses on environmental risk. It argues that risk affects toolkit complexity in such a way that high-risk environments lead to complex toolkits while low-risk environments result in the opposite. This hypothesis has been supported in analyses involving worldwide and continental samples of hunter-gatherers. However, Collard et al.’s (2011) test of the hypothesis using data from the Pacific Northwest failed to support it. For my thesis research I revisited Collard et al.’s study and sought to determine why their results departed from those of the worldwide and continental studies. My study had two parts. In the first, I replicated Collard et al.’s (2011) analyses with a larger dataset. The results of the analyses were largely consistent with those obtained by Collard et al. (2011): I found that the toolkits of the Coast and Plateau were not significantly different despite clear risk-relevant environmental differences between the sub-regions. However, I also found a significant positive correlation between some toolkit variables and the number of salmon species, which is not consistent with the risk hypothesis. In the second part of the study, I approached the evaluation of the risk hypothesis from a different direction. Specifically, I examined the correlation between the average complexity of the tools used to hunt a given species and estimates of the risk involved in capturing that species. I found that species that are difficult to capture and/or have restricted seasonal availability are associated with more complex tools, which is consistent with the risk hypothesis. I conclude from these two sets of results that commonly-used environmental variables like Net Primary Productivity and Effective Temperature are too coarse to accurately characterize the impact of risk on the toolkits of hunter-gatherers at a regional level. I also conclude that the richness and complexity of the toolkits of hunter-gatherers in the Pacific Northwest are not solely affected by risk. Other variables are important and require further investigation.