Risk, mobility or population size? Drivers of technological richness among contact-period western North American hunter–gatherers

Collard, Mark; Buchanan, Briggs; O’Brien, Michael J.; Scholnick, Jonathan

doi:10.1098/rstb.2012.0412

Cited by 72 publications

(81 citation statements)

References 28 publications

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“…Other factors have been proposed to impact cultural complexity. The most prominent of these is environmental risk [45][46][47][48][49][50]. This idea is rooted in the work of Torrence [45], who argued that risk of resource failure affects the complexity of subsistence toolkits, because people create more specialized tools when risk of resource failure is high and more specialized tools tend to be more complex.…”

Section: The Mechanics Of the Population Size Hypothesismentioning

confidence: 99%

The empirical case against the ‘demographic turn’ in Palaeolithic archaeology

Collard

Vaesen

Cosgrove

et al. 2016

Phil. Trans. R. Soc. B

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Recently, it has become commonplace to interpret major transitions and other patterns in the Palaeolithic archaeological record in terms of population size. Increases in cultural complexity are claimed to result from increases in population size; decreases in cultural complexity are suggested to be due to decreases in population size; and periods of no change are attributed to low numbers or frequent extirpation. In this paper, we argue that this approach is not defensible. We show that the available empirical evidence does not support the idea that cultural complexity in hunter-gatherers is governed by population size. Instead, ethnographic and archaeological data suggest that hunter-gatherer cultural complexity is most strongly influenced by environmental factors. Because all hominins were hunter-gatherers until the Holocene, this means using population size to interpret patterns in the Palaeolithic archaeological record is problematic. In future, the population size hypothesis should be viewed as one of several competing hypotheses and its predictions formally tested alongside those of its competitors.This article is part of the themed issue 'Major transitions in human evolution'.

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Section: The Mechanics Of the Population Size Hypothesismentioning

confidence: 99%

The empirical case against the ‘demographic turn’ in Palaeolithic archaeology

Collard

Vaesen

Cosgrove

et al. 2016

Phil. Trans. R. Soc. B

Self Cite

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“…This prediction is supported by evidence from both field and laboratory studies (5-10). However, some authors have been reluctant to embrace this idea, pointing out discrepancies between measures of population size and observed cultural complexity (11)(12)(13)(14). It seems likely that factors other than social network size affect the evolution of cultural complexity, and these factors may obscure the effect of the population size under some conditions.…”

mentioning

confidence: 99%

Partial connectivity increases cultural accumulation within groups

Derex

Boyd

2016

Proc. Natl. Acad. Sci. U.S.A.

239

273

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Complex technologies used in most human societies are beyond the inventive capacities of individuals. Instead, they result from a cumulative process in which innovations are gradually added to existing cultural traits across many generations. Recent work suggests that a population's ability to develop complex technologies is positively affected by its size and connectedness. Here, we present a simple computer-based experiment that compares the accumulation of innovations by fully and partially connected groups of the same size in a complex fitness landscape. We find that the propensity to learn from successful individuals drastically reduces cultural diversity within fully connected groups. In comparison, partially connected groups produce more diverse solutions, and this diversity allows them to develop complex solutions that are never produced in fully connected groups. These results suggest that explanations of ancestral patterns of cultural complexity may need to consider levels of population fragmentation and interaction patterns between partially isolated groups. cultural evolution | innovation | population size | social network | technological trajectory P eople everywhere rely on technology for their survival (1). In even the simplest foraging societies, essential tools are beyond the inventive capacities of individuals; they result from a cumulative process by which innovations are gradually added to existing cultural traits across many generations (2). Recent work suggests that a population's ability to develop complex technologies is positively affected by its size and connectedness (3-5). Large interaction networks allow individuals to learn from many others, and theory predicts that increased opportunities to learn socially reduces the rate of cultural loss and increases the rate at which people improve existing cultural traits. This prediction is supported by evidence from both field and laboratory studies (5-10). However, some authors have been reluctant to embrace this idea, pointing out discrepancies between measures of population size and observed cultural complexity (11)(12)(13)(14). It seems likely that factors other than social network size affect the evolution of cultural complexity, and these factors may obscure the effect of the population size under some conditions.One possibility is that social network structure matters as well. Economists have recently investigated how levels of connectedness in networks affect a group's ability to solve problems of varying complexity (15,16). In agreement with previous work in cultural evolution, they found that high levels of connectivity help groups to solve simple tasks. However, they also suggest that wellconnected networks perform poorly at solving complex tasks (15,16). The complexity of a problem can be represented by mapping all possible solutions onto a measure of performance, which results in what has been called a fitness landscape (17). Simple problems are associated with smooth landscapes, each with a unique optimum that will be reached b...

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“…Further, intermediate-scale environmental change or migration to a new environment also could affect the accumulation and loss of traits that are primarily useful in specific environments (29-33). In addition, the relationship between the number of cultural traits in a population and population size has been debated (4,14,29,(34)(35)(36)(37)(38)(39)(40)(41); this relationship also might depend on the social learning strategies of the population (42, 43). Further, there could be a feedback process between the number of tools in a population and the population size: A larger population might be able to invent and retain more tools, but certain innovations also might support a larger population (44,45).…”

mentioning

confidence: 99%

Evolution in leaps: The punctuated accumulation and loss of cultural innovations

Kolodny

Creanza

Feldman

2015

Proc. Natl. Acad. Sci. U.S.A.

141

185

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Archaeological accounts of cultural change reveal a fundamental conflict: Some suggest that change is gradual, accelerating over time, whereas others indicate that it is punctuated, with long periods of stasis interspersed by sudden gains or losses of multiple traits. Existing models of cultural evolution, inspired by models of genetic evolution, lend support to the former and do not generate trajectories that include large-scale punctuated change. We propose a simple model that can give rise to both exponential and punctuated patterns of gain and loss of cultural traits. In it, cultural innovation comprises several realistic interdependent processes that occur at different rates. The model also takes into account two properties intrinsic to cultural evolution: the differential distribution of traits among social groups and the impact of environmental change. In our model, a population may be subdivided into groups with different cultural repertoires leading to increased susceptibility to cultural loss, whereas environmental change may lead to rapid loss of traits that are not useful in a new environment. Taken together, our results suggest the usefulness of a concept of an effective cultural population size.T he breadth and diversity of cultural traits and their rates of accumulation have received a great deal of scholarly attention. Scientific knowledge in many fields appears to accumulate exponentially (1, 2). However, although the number of tool types in the archaeological record also seems to fit this pattern of exponential increase broadly (3), the number of tools and other cultural traits does not increase steadily and monotonically over time. Depending on the timescale studied, change in tool repertoire may appear punctuated and stepwise. Long, seemingly static, periods are interspersed between "cultural explosions," periods of sudden cultural accumulation (3-13). Further, in some populations, there is evidence that whole suites of cultural traits, such as the ability to make tools, clothing, and fire (14-16), may be lost, defying the general trend of cultural accumulation over time (4,7,8).Reasons for the sudden changes in hominid material culture in the archaeological record continue to be debated; they could be related to demographic factors (17), rapid cognitive change (18-21), relatively sudden changes in hand morphology (22, 23), or dramatic climatic shifts (10,(24)(25)(26)(27)(28). Further, intermediate-scale environmental change or migration to a new environment also could affect the accumulation and loss of traits that are primarily useful in specific environments (29-33). In addition, the relationship between the number of cultural traits in a population and population size has been debated (4,14,29,(34)(35)(36)(37)(38)(39)(40)(41); this relationship also might depend on the social learning strategies of the population (42, 43). Further, there could be a feedback process between the number of tools in a population and the population size: A larger population might be able to invent and retain m...

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Risk, mobility or population size? Drivers of technological richness among contact-period western North American hunter–gatherers

Cited by 72 publications

References 28 publications

The empirical case against the ‘demographic turn’ in Palaeolithic archaeology

The empirical case against the ‘demographic turn’ in Palaeolithic archaeology

Partial connectivity increases cultural accumulation within groups

Evolution in leaps: The punctuated accumulation and loss of cultural innovations

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