The evolution of (intergroup) peace hinges on how we define groups and peace.

Glowacki defines peace as harmonious relationships between groups maintained without the threat of violence, where groups can be anything from families to nation states. However, defining such contentious concepts like "peace" and "groups" is a difficult task, and we discuss the implications of Glowacki's definitions for understanding intergroup relationships and their evolutionary history.

Long-distance social relationships can both undercut and promote local natural resource management.

The management of large common-pool resources, like fisheries and forests, is more difficult when more people and more communities can access them-a particular problem given increased population sizes, higher mobility and globalized trade in the Anthropocene. Social relationships spanning communities, such as kin relationships, business or trade relationships and friendships, can make management even more challenging by facilitating and transmitting norms of overharvesting. However, these long-distance relationships can also bolster management by transmitting norms for sustainability, promoting interdependence and laying the groundwork for nested management systems.

Climate change adaptation needs a science of culture.

There is global consensus that we must immediately prioritize climate change adaptation-change in response to or anticipation of risks from climate change. Some researchers and policymakers urge 'transformative change', a complete break from past practices, yet report having little data on whether new practices reduce the risks communities face, even over the short term. However, researchers have some leads: human communities have long generated solutions to changing climate, and scientists who study culture have examples of effective and persistent solutions.

Distinguishing Intergroup and Long-Distance Relationships.

Intergroup and long-distance relationships are both central features of human social life, but because intergroup relationships are emphasized in the literature, long-distance relationships are often overlooked. Here, we make the case that intergroup and long-distance relationships should be studied as distinct, albeit related, features of human sociality. First, we review the functions of both kinds of relationship: while both can be conduits for difficult-to-access resources, intergroup relationships can reduce intergroup conflict whereas long-distance relationships are especially effective at buffering widespread resource shortfalls.

Want climate-change adaptation? Evolutionary theory can help.

The idea of adaptation, in which an organism or population becomes better suited to its environment, is used in a variety of disciplines. Originating in evolutionary biology, adaptation has been a central theme in biological anthropology and human ecology. More recently, the study of adaptation in the context of climate change has become an important topic of research in the social sciences.

Human adaptation to climate change: An introduction to the special issue.

Objectives: Despite our focus on adaptation and human responses to climate, evolutionary and biological anthropologists (EBAs) are largely absent from conversations about contemporary "climate-change adaptation," a term popular in other disciplines, the development world, and related policy decisions. EBAs are missing a big opportunity to contribute to impactful, time-sensitive applied work: we have extensive theoretical and empirical knowledge pertinent to conversations about climate-change adaptation and to helping support communities as they cope. This special issue takes a tour of EBA contributions to our understanding of climate-change adaptation, from data on past and contemporary human communities to theoretically informed predictions about how individuals and communities will respond to climate change now and in the future.

Do people manage climate risk through long-distance relationships?

Objectives: Long-distance social relationships have been a feature of human evolutionary history; evidence from the paleoanthropological, archeological, and ethnographic records suggest that one function of these relationships is to manage the risk of resource shortfalls due to climate variability. We should expect long-distance relationships to be especially important when shortfalls are chronic or temporally positively autocorrelated, as these are more likely to exhaust local adaptations for managing risk. Further, individuals who experience shortfalls not as rare shocks, but as patterned events, should be more likely to pay the costs of maintaining long-distance relationships.

Navigating cross-cultural research: methodological and ethical considerations.

The intensifying pace of research based on cross-cultural studies in the social sciences necessitates a discussion of the unique challenges of multi-sited research. Given an increasing demand for social scientists to expand their data collection beyond WEIRD (Western, educated, industrialized, rich and democratic) populations, there is an urgent need for transdisciplinary conversations on the logistical, scientific and ethical considerations inherent to this type of scholarship. As a group of social scientists engaged in cross-cultural research in psychology and anthropology, we hope to guide prospective cross-cultural researchers through some of the complex scientific and ethical challenges involved in such work: (a) study site selection, (b) community involvement and (c) culturally appropriate research methods.

Preferences and constraints: the value of economic games for studying human behaviour.

As economic games have spread from experimental economics to other social sciences, so too have critiques of their usefulness for drawing inferences about the 'real world'. What these criticisms often miss is that games can be used to reveal individuals' private preferences in ways that observational and interview data cannot; furthermore, economic games can be designed such that they provide insights into real-world behaviour. Here, we draw on our collective experience using economic games in field contexts to illustrate how researchers can strategically alter the framing or design of economic games to draw inferences about private-world or real-world preferences.

The evolution of intergroup tolerance in nonhuman primates and humans.

Primate individuals use a variety of strategies in intergroup encounters, from aggression to tolerance; however, recent focus on the evolution of either warfare or peace has come at the cost of characterizing this variability. We identify evolutionary advantages that may incentivize tolerance toward extra-group individuals in humans and nonhuman primates, including enhanced benefits in the domains of transfer, mating, and food acquisition. We highlight the role these factors play in the flexibility of gorilla, chimpanzee, bonobo, and human behavior.

Political Orientation Predicts Credulity Regarding Putative Hazards.

To benefit from information provided by other people, people must be somewhat credulous. However, credulity entails risks. The optimal level of credulity depends on the relative costs of believing misinformation and failing to attend to accurate information.

Risk buffering and resource access shape valuation of out-group strangers.

Unlike other primates, humans exhibit extensive inter-group tolerance and frequently build relationships with out-group members. Despite its common occurrence, little is known about the conditions leading to out-group relationship building in humans. What are the social and ecological factors promoting valuation of out-group members as potential social partners? Do they differ from those promoting valuation of in-group members? We propose that opportunities for non-local resource access and resource buffering, crucial in the human foraging niche, will increase valuation of out-group strangers.

Small-scale societies exhibit fundamental variation in the role of intentions in moral judgment.

Intent and mitigating circumstances play a central role in moral and legal assessments in large-scale industrialized societies. Although these features of moral assessment are widely assumed to be universal, to date, they have only been studied in a narrow range of societies. We show that there is substantial cross-cultural variation among eight traditional small-scale societies (ranging from hunter-gatherer to pastoralist to horticulturalist) and two Western societies (one urban, one rural) in the extent to which intent and mitigating circumstances influence moral judgments.

Corruption and the Other(s): Scope of Superordinate Identity Matters for Corruption Permissibility.

The decision to engage in corruption-public and private corruption, nepotism, and embezzlement-is often attributed to rational actors maximizing benefits to themselves. However, the importance of reciprocal relationships in humans suggests that an actor may weigh the costs of harms of her corrupt behavior to individuals who may generate future benefits for her. We hypothesize that actors who have a larger circle of actual and potential social partners will have more individuals to consider when generating harms and will thus be less likely to find corrupt acts permissible than actors with smaller circles of valued others.

Moral parochialism and contextual contingency across seven societies.

Human moral judgement may have evolved to maximize the individual's welfare given parochial culturally constructed moral systems. If so, then moral condemnation should be more severe when transgressions are recent and local, and should be sensitive to the pronouncements of authority figures (who are often arbiters of moral norms), as the fitness pay-offs of moral disapproval will primarily derive from the ramifications of condemning actions that occur within the immediate social arena. Correspondingly, moral transgressions should be viewed as less objectionable if they occur in other places or times, or if local authorities deem them acceptable.

Negatively-biased credulity and the cultural evolution of beliefs.

The functions of cultural beliefs are often opaque to those who hold them. Accordingly, to benefit from cultural evolution's ability to solve complex adaptive problems, learners must be credulous. However, credulity entails costs, including susceptibility to exploitation, and effort wasted due to false beliefs.

Patterns of senescence in human cardiovascular fitness: VO2 max in subsistence and industrialized populations.

Objectives: This study explores whether cardiovascular fitness levels and senescent decline are similar in the Tsimane of Bolivia and Canadians, as well as other subsistence and industrialized populations. Among Tsimane, we examine whether morbidity predicts lower levels and faster decline of cardiovascular fitness, or whether their lifestyle (e.g.

Importing social preferences across contexts and the pitfall of over-generalization across theories.

Claims regarding negative strong reciprocity do indeed rest on experiments lacking established external validity, often without even a small "menu of options." Guala's review should prompt strong reciprocity proponents to extend the real-world validity of their work, exploring the preferences participants bring to experiments. That said, Guala's approach fails to differentiate among group selection approaches and glosses over cross-cultural variability.