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.

Among residents of an informal housing area in Cairo, we examine how dictator giving varies by the social distance between subjects - friend versus stranger - and by the anonymity of the dictator. While giving to strangers is high under anonymity, we find - consistent with Leider et al. (2009) -...

We present evidence from a natural field experiment and structural model designed to shed light on the efficacy of alternative fundraising schemes. In conjunction with the Bavarian State Opera, we mailed 25,000 opera attendees a letter describing a charitable fundraising project organized by the...

We use a range of dictator game experiments to investigate whether people avoid information altruistically. After learning about a product with positive externalities, a consumer may avoid learning the cost of the product so that she does not hesitate to act altruistically. We find that although...

In an experiment, we test the impact of quality certificates on donations to a charity. Compared to the control group, participants presented with a quality certificate chose higher donations by around 10% and reported higher trust towards the same charity. The choice of donation values over...

We provide the first field evidence pointing at the role of pure self-image, inde-pendent of social image, in charitable giving. In an online fundraising campaign for a social youth project run on an opera ticket booking platform we document how individuals appear to engage in self-deception to...

We study intertemporal crowding between two fundraising campaigns for the same charitable organization by manipulating donors’ beliefs about the likelihood of future campaigns in two subsequent field experiments. The data shows that initial giving is decreasing in the likelihood of a future...

Experimental research on generosity has focused predominantly on behavior in the monetary domain, although many real life decisions take place in the non-monetary domain. Investigating generosity preferences in the non-monetary domain is important to understand a large class of situations...

A model of a two-candidate election is developed in which the candidates are mainly office-motivated but also to some arbitrarily small extent policy-motivated, and their chosen platforms are to some arbitrarily small extent noisy. The platforms’ being noisy means that if a candidate has...

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...