Altruists and envious people who meet in contests are symbionts. They do better than a population of narrowly rational individuals. If there are only altruists and envious individuals, a particular mixture of altruists and envious individuals is evolutionarily stable.

In 2005, the Democratic National Committee adopted the 50-state strategy in lieu of the strategy of focusing solely on battleground states. The rationale given for this move is that campaign expenditures are durable outlays that impact both current and future campaigns. This paper investigates...

Consider a committee that in the past has made a promise not to confiscate the profits from a foreign investor. After the investment has taken place, there is a material benefit if the committee decides to default on the earlier promise. But there are also some small moral costs for those who...

It can be advantageous for an office motivated party A to spend effort to make it public that a group of voters will lose from party A’s policy proposal. Such effort is called inverse campaigning. The inverse campaigning equilibria are described for the case where the two parties can...

Does online fundraising increase charitable giving? Using the Facebook advertising tool, we implemented a natural field experiment across Germany, randomly assigning almost 8,000 postal codes to Save the Children fundraising videos or to a pure control. We studied changes in the donation revenue...

When asking for donations, charitable organizations often use suggestions concerning the amount of potential contributions. However, the evidence concerning the effects of such suggestions is scarce and inconsistent. Unlike the majority of existing studies concerned with small-money...

We investigate the effects of team competition on pro-social lending activity on Kiva.org, the first microlending website to match lenders with entrepreneurs in developing countries. Using naturally occurring field data, we find that lenders who join teams contribute 1.2 more loans ($30-$42) per...

Is there a way of matching donations that avoids crowding out? We introduce a novel matching method where the matched amount is allocated to a different project, present some simple theoretical considerations that predict reduced crowding out or more crowding in (depending on the degree of...