Highlights•We review randomized field experiments in real-world cooperation
settings.•Material rewards and increasing efficacy change costs and benefits of …

Using field experiments, scholars can identify causal effects via randomization while
studying people and groups in their naturally occurring contexts. In light of renewed interest …

The oxygenation of Earth's surface fundamentally altered global biogeochemical cycles and
ultimately paved the way for the rise of metazoans at the end of the Proterozoic. However …

Through good and bad economic times, charitable gifts have continued to roll in largely
unabated over the past half century. In a typical year, total charitable gifts of money now …

Donors tend to avoid charities that dedicate a high percentage of expenses to administrative
and fundraising costs, limiting the ability of nonprofits to be effective. We propose a solution …

A defining aspect of human cooperation is the use of sophisticated indirect reciprocity. We
observe others, talk about others, and act accordingly. We help those who help others, and …

Ideal for students, novice researchers, or professionals, this indispensable resource serves
as a road map for readers who need to analyze and apply research findings. It helps them …

The conflict between pro-self and pro-social behaviour is at the core of many key problems
of our time, as, for example, the reduction of air pollution and the redistribution of scarce …

We donate billions to charities each year, yet much of our giving is ineffective. Why are we
motivated to give but not to give effectively? Building on evolutionary game theory, we argue …

We present evidence from a natural field experiment designed to shed light on the efficacy of
fundraising schemes in which donations are matched by a lead donor. In conjunction with …