A large literature shares the view that social norms shape human cooperation, but without a
clean empirical identification of the relevant norms almost every behaviour can be …

Some of the most fundamental questions concerning our evolutionary origins, our social
relations, and the organization of society are centred around issues of altruism and …

The existence of social norms is one of the big unsolved problems in social cognitive
science. Although no other concept is invoked more frequently in the social sciences, we still …

Game theory is central to understanding human behavior and relevant to all of the
behavioral sciences—from biology and economics, to anthropology and political science …

Our intestine is the site of an extraordinarily complex and dynamic environmentally
transmitted consortial symbiosis. The molecular foundations of beneficial symbiotic host …

How do human groups maintain a high level of cooperation despite a low level of genetic
relatedness among group members? We suggest that many humans have a predisposition …

Two experimental tasks in psychology, the two-stage gambling game and the Prisoner's
Dilemma game, show that people violate the sure thing principle of decision theory. These …

The transfer of food among group members is a ubiquitous feature of small-scale forager
and forager-agricultural populations. The uniqueness of pervasive sharing among humans …

Animals often aid others without gaining any immediate benefits. Although these acts seem
to reduce the donor's fitness, they are only apparently altruistic. Donors typically help …

The various behavioral disciplines model human behavior in distinct and incompatible ways.
Yet, recent theoretical and empirical developments have created the conditions for …