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 …

Overall, people want to behave ethically. In some cases, temptation steers them away from
ethical behavior. In other cases, purely ethical behavior is not possible, because the same …

Humans operate in groups that are oftentimes nested in multilayered collectives such as
work units within departments and companies, neighborhoods within cities, and regions …

Like other group-living species, humans often cooperate more with an in-group member
than with out-group members and strangers. Greater in-group favoritism should imply that …

Intergroup violence is challenging to understand: why do individuals cooperate to harm
members of other groups when they themselves may be killed or injured? Despite progress …

Beginning in 2022, a surge in foreign travel to Ukraine to participate in both combat and non-
combat tourism from volunteers travelling to war-torn countries prompted new lines of …

Intergroup conflict has been conceptualized as a strategic interaction (conflict-as-contest)
and separately as a pathological condition (conflict-as-disease). We highlight how insights …

We describe a team game that implements a social dilemma between ingroup cooperation
and defection by self-enriching outgroup exchange. We test hypotheses derived from social …

The evolution of parochial altruism goes hand in hand with intergroup conflict. Helping other
group members is evolutionary stable in the presence of an outside threat (Bowles et al …

Conflict plays a profound role in the lives of individuals, organizations, and entire societies–
and has become an ever-expanding area of interdisciplinary research. This special issue …