Human between-group interactions are highly variable, ranging from violent to tolerant and
affiliative. Tolerance between groups is linked to our unique capacity for large-scale …

Group territory defence poses a collective action problem: individuals can free-ride,
benefiting without paying the costs. Individual heterogeneity has been proposed to solve …

Highlights•Humans engage in a wide range of group-level cooperation and competition.•We
investigate the evolution of group cooperation and its underlying group-mindedness.•We …

Individuals of social species experience competitive costs and social benefits of group living.
Substantial flexibility in humans' social structure and the combination of different types of …

The evolution of our tendencies for warfare and peacemaking is of urgent interest. Between-
group competition over resources is often invoked to explain out-group hostility and in-group …

Lethal intergroup encounters occur in many species because of sexual selection. While
documented in mountain gorillas, they are absent in western gorillas as, instead, it is …

In humans, puberty initiates a period of rapid growth, change, and formative
neurobehavioral development. Brain and behavior changes during this maturational window …

Maternal lactational investment can affect female reproductive rates and offspring survival in
mammals and can be biased towards infants of one sex. We compared estimates of lactation …

Like many animals, adult male chimpanzees often compete for a limited number of mates.
They fight other males as they strive for status that confers reproductive benefits and use …

Males that behave violently to achieve social and reproductive objectives are a widespread
phenomenon among mammals, as well as humans. Because this kind of behaviour can be …