Previous studies have yielded contradictory results on the relationship between population size and cultural evolution. Focusing on tool complexity these authors introduce the risk of resource failure as a possible confounding variable. They conclude that population does not predict tool kit complexity when controlling on other factors. There were significant correlations between tool kit complexity and some of the resource measures.

Seeking to resolve contradictions between previous studies, these authors conduct empirical analysis on the relationship between population size and cultural evolution. Results indicate that population size influences toolkit richness and complexity, even when proxies for risk of resource failure are introduced in the regression model. Authors speculate that the association is weaker for hunter-gatherers because those societies are more affected by risk of resource failure and have institutions that facilitate cultural evolution despite smaller population size. There also may be a threshold effect in the influence of population size on toolkit structure.

This study tests four hypotheses that propose potential environmental and social predictors of toolkit size and complexity among hunter-gatherers. Hypotheses predicting relationships between population size, residential mobility, type of food resources and toolkit structure are not supported. Risk of resource failure is the only variable that is significantly associated with toolkit structure.

This paper builds off previous research into the effect of population size and resource risk on complexity of subsistence technology by investigating the relationship between these independent variables and total number of material items and techniques used by various western North American hunter-gatherer groups. This tally of total technological complexity is found to be insignificantly related to population size or residential mobility; however, there is a significant correlation in the expected direction between technological complexity and one measure of resource risk (mean annual temperature during driest month). Tying this finding to previous analyses of subsistence technologies, the authors theorize that environmental risk is a pervasive driver of technological ingenuity and cultural evolution.

Prior research by Oswalt (1973, 1976) and Torrence (1983, 2001) has suggested that risk of resource failure is a significant predictor of toolkit complexity and diversity among hunter-gatherers. In this paper, the same relationship is tested among small-scale herding and farming groups. However, no significant correlation is discovered between any measure of resource risk and any measure of toolkit complexity. The researchers suggest that this absence may be the result of greater reliance on non-technological diversification methods among farmers (i.e. spatial diversification, mixed farming, intercropping), or of other unaccounted-for sources of risk (i.e. intergroup raiding and warfare).

The researchers test the relationship between toolkit complexity and diversity as defined by Oswalt (1973) and environmental and demographic variables. Neither population size nor risk of resource failure predict toolkit characteristics among all groups in the sample. However, population size is significantly positively correlated with toolkit diversity and complexity among food-producers, whereas environmental factors indicating risk of resource failure are significantly positively correlated among hunter-gatherers. This leads the researchers to suggest that food-producers' effectiveness at niche construction is a result of their large population size, which thus has a larger effect on toolkit composition than does environmental risk relative to hunter-gatherers.

The authors use ethnographic data to try to shed light on the prevalence of missing phalanges in Upper Paleolithic cave images. Searching eHRAF World Cultures, they found evidence of finger amputation in 121 societies. These accounts cast doubt on two common theories: 1) that cave images reflect sign language or 2) counting systems. Researchers argue the intentional removal of fingers could be sorted into the 10 following categories: sacrifice (for deities), mourning (for grief), identity (for group membership), medical (to heal sickness), marriage (status marker), punishment (for deeds), veneration (for worship), offering (post mortem for deities), trophy (an enemies fingers), and talisman (assist with magic). They argue that sacrifice was the most likely reason for the missing finger images in Upper Paleolithic caves.

This study analyzed fire use in 93 hunter-gatherer groups based on ethnographic texts from eHRAF in order to improve our understanding of early hominin fire use. The researchers collected data on the groups' methods of making fire, the ways they used fire, and when and where they created fires. The study found that some groups either did not know how to make fire using traditional methods or had very few members who knew how to use such methods. The study also found that many groups preferred to preserve fire rather than create it anew, even carrying it between camps. Beyond this, the ways in which fire was created and used varied widely between hunter-gatherer groups. These findings have implications for understanding early pyrotechnology and the interpretation of the presence or absence of fire residues in the Palaeolithic archaeological record. The results suggest that the absence of fire residues may indicate the absence of fire-making knowledge and skills rather than just taphonomic processes, and that the presence of fire residues does not necessarily indicate the ability to manufacture fire.

Using Bayesian phylogenetic analysis, the authors ask: "Do cultural traits exhibit different histories of transmission?". They explore two competing models regarding Iranian tribal textile tradition. First, the "hierarchically integrated system hypothesis" emphasizes the importance of a core tradition and peripheral traits that are shared among contemporaneous populations. Second, the "multiple coherent units hypothesis" suggests that the groups of cultural traits have different transmission histories. The results show more support towards the "multiple coherent units hypothesis", specifically that pile-weave designs emerge as a cultural unit with a unique phylogenetic history compared to other textile characters.