Although humans qualify as one of the most cooperative animal species, the scale of violent intergroup conflict among them is unparalleled. Explanations of the underlying motivation to participate in an intergroup conflict, however, remain unsatisfactory. While previous research shows that intergroup conflict increases ‘in-group love’, it fails to identify robust triggers of ‘out-group hate’. Here, we present a controlled laboratory experiment, which demonstrates that ‘out-group hate’ can be provoked systematically. We find direct and causal evidence that the intention to protect the in-group is not only a crucial motivator of ‘out-group hate’ in defensive reactions, but also promotes preemptive offensive actions against out-group threat. Hence, the strength of ‘out-group hate’ depends on whether the own group is perceived to be on the offensive or the defensive side of the conflict. This finding improves our understanding of the escalation of intergroup conflicts and may have important implications for their prevention, as we find in our experiment that removing out-group threat substantially reduces intergroup aggression, leading to full peace.

What Makes People Go to War? Defensive Intentions Motivate Retaliatory and Preemptive Intergroup Aggression

When one individual helps another, it benefits the recipient and may also gain a reputation for being cooperative. This may induce others to favour the helper in subsequent interactions, so investi...

The benefits of being seen to help others: indirect reciprocity and reputation-based partner choice.

Gossip—a sender communicating to a receiver about an absent third party—is hypothesized to impact reputation formation, partner selection, and cooperation. Laboratory experiments have found that people gossip about others' cooperativeness and that they use gossip to condition their cooperation. Here, we move beyond the laboratory and test several predictions from theories of indirect reciprocity and reputation-based partner selection about the content of everyday gossip and how people use it to update the reputation of others in their social network. In a Dutch community sample (N = 309), we sampled daily events in which people either sent or received gossip about a target over 10 days (ngossip = 5284). Gossip senders frequently shared information about targets’ cooperativeness and did so in ways that minimize potential retaliation from targets. Receivers overwhelmingly believed gossip to be true and updated their evaluation of targets based on gossip. In turn, a positive shift in the evaluation of a target was associated with higher intentions to help them in future interactions, and with lower intentions to avoid them in the future. Thus, gossip is used in daily life to impact and update reputations in a way that enables partner selection and indirect reciprocity.

https://royalsocietypublishing.org/doi/pdf/10.1098/rstb.2020.0301

Gossip and reputation in everyday life

Significance Ethnic divides play a major role in many armed conflicts around the world and might serve as predetermined conflict lines following rapidly emerging societal tensions arising from disruptive events like natural disasters. We find evidence in global datasets that risk of armed-conflict outbreak is enhanced by climate-related disaster occurrence in ethnically fractionalized countries. Although we find no indications that environmental disasters directly trigger armed conflicts, our results imply that disasters might act as a threat multiplier in several of the world’s most conflict-prone regions. Social and political tensions keep on fueling armed conflicts around the world. Although each conflict is the result of an individual context-specific mixture of interconnected factors, ethnicity appears to play a prominent and almost ubiquitous role in many of them. This overall state of affairs is likely to be exacerbated by anthropogenic climate change and in particular climate-related natural disasters. Ethnic divides might serve as predetermined conflict lines in case of rapidly emerging societal tensions arising from disruptive events like natural disasters. Here, we hypothesize that climate-related disaster occurrence enhances armed-conflict outbreak risk in ethnically fractionalized countries. Using event coincidence analysis, we test this hypothesis based on data on armed-conflict outbreaks and climate-related natural disasters for the period 1980–2010. Globally, we find a coincidence rate of 9% regarding armed-conflict outbreak and disaster occurrence such as heat waves or droughts. Our analysis also reveals that, during the period in question, about 23% of conflict outbreaks in ethnically highly fractionalized countries robustly coincide with climatic calamities. Although we do not report evidence that climate-related disasters act as direct triggers of armed conflicts, the disruptive nature of these events seems to play out in ethnically fractionalized societies in a particularly tragic way. This observation has important implications for future security policies as several of the world’s most conflict-prone regions, including North and Central Africa as well as Central Asia, are both exceptionally vulnerable to anthropogenic climate change and characterized by deep ethnic divides.

Armed-Conflict Risks Enhanced by Climate-Related Disasters in Ethnically Fractionalized Countries

Perceptions of conflict: Parochial cooperation and outgroup spite revisited

Group Cooperation, Carrying-Capacity Stress, and Intergroup Conflict.

Intergroup conflict can be modeled as a two-level game of strategy in which prosociality can take the form of trust and cooperation within groups or between groups. We review recent work, from our own laboratory and that of others, that shows how biological and sociocultural mechanisms that promote prosocial preferences and beliefs create in-group bounded, parochial cooperation, and, sometimes, parochial competition. We show when and how parochial cooperation and competition intensify rather than mitigate intergroup conflict.

Prosociality as a foundation for intergroup conflict.

Humans care about having a positive reputation, which may prompt them to help in scenarios where the return benefits are not obvious. Various game-theoretical models support the hypothesis that con...

The psychological foundations of reputation-based cooperation

Humans differ in their preferences for personal rewards, fairness and others' welfare. Such social preferences predict trust, public goods provision and mutual gains bargaining and have been linked to neural activity in regions involved in reward computation, cognitive control and perspective-taking. Although shaped by culture, social preferences are relatively stable across time, raising the question whether differences in brain anatomy predict social preferences and their key components-concern for personal outcomes and concern for others' outcomes. Here, we examine this possibility by linking social preferences measured with incentivized economic games to 74 cortical parcels in 194 healthy humans. Neither concerns for personal outcomes nor concerns for the outcomes of others in isolation were related to anatomical differences. However, fitting earlier findings, social preferences positively scaled with cortical thickness in the left olfactory sulcus, a structure in the orbital frontal cortex previously shown to be involved in value-based decision-making. Consistent with work showing that heavier usage corresponds to larger brain volume, findings suggest that pro-social preferences relate to cortical thickness in the left olfactory sulcus because of heavier reliance on the orbital frontal cortex during social decision-making.

/pdf/social-preferences-correlate-with-cortical-thickness-of-the-x6qwgtg86a.pdf

Andrea Fariña

Papers

Group Cooperation, Carrying-Capacity Stress, and Intergroup Conflict.

The benefits of being seen to help others: indirect reciprocity and reputation-based partner choice.

Prosociality as a foundation for intergroup conflict.

The psychological foundations of reputation-based cooperation

Social preferences correlate with cortical thickness of the orbito-frontal cortex.