Norms are a foundational concept in sociology. Following a period of skepticism about
norms as overly deterministic and as paying too little attention to social conflict, inequalities …

In explaining the sources of cooperation and prosocial behavior, psychologists, behavioral
economists, and biologists often focus on factors internal to the individual, such as altruistic …

Observation of leadership in small-scale societies offers unique insights into the evolution of
human collective action and the origins of sociopolitical complexity. Using behavioural data …

Conflict with conspecifics from neighbouring groups over territory, mating opportunities and
other resources is observed in many social organisms, including humans. Here we …

I review the theoretical and experimental literature on the collective action problem in groups
whose members differ in various characteristics affecting individual costs, benefits and …

People routinely cooperate with each other, even when cooperation is costly. To further
encourage such pro-social behaviors, recipients often respond by providing additional …

To determine the role of moral norms in cooperation and punishment, we examined the
effects of a moral-framing manipulation in a Prisoner's Dilemma game with a costly …

Individuals usually punish free riders but refuse to sanction those who cooperate but do not
punish. This missing second-order peer punishment is a fundamental problem for the …

Monitoring with implicated punishment is common in human societies to avert freeriding on
common goods. But is it effective in promoting public cooperation? We show that the …

In many species, mutual cooperation is stabilized by forms of policing and peer punishment:
if cheaters are punished, there is a strong selective pressure to cooperate. Most human …