The biological success derived from cumulative culture and cooperation and their association with ancestral group structure is examined. It is suggested that inclusive fitness cannot explain extensive cooperation in hunter-gatherers because in most of the foraging societies examined, most individuals in residential groups are unrelated. These large social networks may explain why humans are capable of social learning.

Researchers examined and coded motor skills used in coalitional play fighting in hunter-gatherer societies to investigate if it was a product of agriculture/industry, or occurred more broadly in non-agricultural populations. Sampling 100 societies from the Ethnographic Atlas, researchers found at least one predictor of such motor patterns showing coalitional play fighting amongst all hunter gatherer groups with information, and multiple predictors among most of the 46 groups. Researchers theorize this coalitional play fighting was training for intergroup aggression such as lethal raids.

This chapter includes cross-cultural tests of the relationship between social complexity of hunter-gatherer groups and warfare. Results suggest that more complex and equestrian hunter-gatherer societies tend to be more war-like and less complex hunter gatherer societies tend to be more peaceful.

The authors present a bioeconomic model of hunter-gatherer foraging effort to quantitatively represent forager intensification. Using cross-cultural data, the model is evaluated as a means to better understand variation in residential stability and resource ownership.

This study, primarily a review on the evolution of the human diet, also includes a small study on the distribution of meat-eating and its relationship with climate and cultural factors, namely subsistence type. The authors find that societies with subsistence strategies that prioritize fishing, hunting, or pastoralism also tend to consume more animal products, whereas those that focus on agriculture have more plant-based diets. The authors argue that these small-scale societies have a healthier approach to diet than industrialized societies regardless of their subsistence type or meat consumption.

Previous research into the origins of human violence and warfare has oftentimes been inconclusive and controversial. This paper examines two alternative theories as to the evolution of human violence using archaeological records on sharp force trauma (SFT) and blunt force trauma (BFT). The study is limited to 13 different California ethnolinguistic groups. Researchers find that violence is not predicted by sociopolitical complexity, but rather by environmental productivity. This supports the idea that in contexts of resource scarcity, the perceived benefits to engage in lethal aggression may outweigh perceived costs.

Archaeologists often interpret found portable artifacts (e.g. dolls, miniature weapons) as ritual objects. But it is argued that they might instead reflect children's play activities. This descriptive study analyzes the artifacts and context of children's play using the literature and the ethnographic record of 82 hunter-gatherer societies. Six signs of the presence of children, that might survive in archaeological record are noted, which may suggest that many "ritual activities" are children's activities.

The authors assemble an inventory of burning practices based on cross-cultural ethnographic data in order to elucidate or provide interpretive range for burning patterns seen in the archaeological record. Although no explicit hypotheses are tested, descriptive generalizations are proposed.

This article hypothesizes that ritual ecstasy was selected for as a way for hunter-gatherers to cope with resource uncertainty by unifying separate groups. Results support this hypothesis and suggest a relationship between resource stress and deities as well as dependence on animals and presence of zoomorphic deities.

In this chapter of 'Beyond War,' Douglas critiques previous codes of warfare to make a distinction between feuding and warring. A test of warfare and level of social complexity among hunter-gatherers is conducted. Results indicate that complex hunter-gatherers make war while a majority of simple hunter-gatherers do not.