Recent research into the public’s attitude toward the use of nuclear weapons repeats long-standing mistakes in how international relations theorists think about morality. Falsely equating consequentialism with state egoism and normative obligations with restrictions on the use of weapons of mass destruction implies that ethically motivated beliefs about foreign affairs must be other-regarding and that other-regarding behavior is not utilitarian in character. Drawing on empirical research into moral psychology, we argue that liberal, other-regarding morality is only one kind of ethical foundation. Alternative moral concerns such as retribution, deference to authority, and in-group loyalty also help to determine foreign policy beliefs. We find that all three are associated with support for the use of nuclear weapons in the American public. Our survey respondents act as moral utilitarians who weigh different ethical considerations in forming their judgments.

W hile we know much about what differentiates the conflict behavior of democracies from autocracies, we know relatively little about why some democracies are more belligerent than others. In contrast to existing studies, I argue that it is public opinion and not institutions that drives these differences. All democratic leaders have an incentive to take public opinion into account, but public opinion is not the same everywhere. Individuals' attitudes towards war are shaped by core beliefs about revenge, which vary across countries. Leaders with more vengeful populations will be more likely to initiate conflicts because they generate popular support for war more effectively. Using retention of capital punishment as a proxy for broad endorsement of revenge, I find that democracies that have retained the death penalty for longer periods of time are significantly more likely to initiate conflicts. This research has important implications for existing theories of democracy and war.

Visual information can influence animal behavior and habitat use in diverse ways. Visibility is the property that relates 3D habitat structure to accessibility of visual information. Despite the importance of visibility in animal ecology, this property remains largely unstudied. Our objective was to assess how habitat structure from diverse environments and animal position within that structure can influence visibility. We gathered terrestrial lidar data (1 cm at 10 m) in four ecosystems (forest, shrub-steppe, prairie, and desert) to characterize viewsheds (i.e., estimates of visibility based on spatially explicit sightlines) from multiple vantage points. Both ecosystem-specific structure and animal position influenced potential viewsheds. Generally, as height of the vantage point above the ground increased, viewshed extent also increased, but the relationships were not linear. In low-structure ecosystems (prairie, shrub-steppe, and desert), variability in viewsheds decreased as vantage points increased to heights above the vegetation canopy. In the forest, however, variation in viewsheds was highest at intermediate heights, and markedly lower at the lowest and highest vantage points. These patterns are likely linked to the amount, heterogeneity, and distribution of vegetation structure occluding sightlines. Our work is the first to apply a new method that can be used to estimate viewshed properties relevant to animals (i.e., viewshed extent and variability). We demonstrate that these properties differ across terrestrial landscapes in complex ways that likely influence many facets of animal ecology and behavior.

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Mammals use sound for a variety of purposes, such as detecting the presence of others and maintaining social bonds. Much research on mammalian acoustics has been focussed on marine mammals and bats; less has considered terrestrial species. Our goal was to review knowledge about the role of acoustics in the behaviour and ecology of terrestrial mammals and to develop a conceptual framework that contextualises the knowledge. The purpose of the framework was to enable researchers to place their work in a broader understanding of the acoustics of terrestrial mammals, as well as to support them to articulate and explore new questions. We conducted a keyword search in Web of Science and removed papers that did not meet our criteria, resulting in 228 reviewed papers. We scored these for keywords and used concept maps to identify broad patterns. Of the 228 papers, 219 were focussed on acoustic communication. We therefore structured our Signaller–Receiver Conceptual Framework around factors that influence signallers (i.e. mammals producing sound) and receivers (i.e. mammals receiving sound). Factors that influence signallers were placed into two categories – those that influence call emission and those that influence call structure. Factors that influence receivers also fell into two categories – those that influence detection of sound and those that influence responses to sound. We added an additional receiver category – responses to sound. We present the framework in terms of five types of factors (environmental, social, morphological and physiological, state‐related factors, and other) and how they influence both signallers and receivers. Our review is the first to detail the range of factors influencing acoustic ecology of terrestrial mammals, and our framework provides context for the articulation of hypotheses that integrate multiple factors, and so can help researchers place their work in a broader context.