Pledges are ubiquitous in charitable giving, but they are often reneged upon. To investigate whether adding the phrase “I swear” to pledge language can reduce pledge reneging, we conduct a series of experiments in the context of online fundraising. We find that including “I swear” at the beginning of the pledge language significantly increases immediate giving and pledge fulfillment, with more individuals switching from pledging to giving immediately. We also observe individual heterogeneity in moral identity: Our findings are present among individuals with low moral identity, but not among those with high moral identity. Our paper presents a simple and no-cost strategy for increasing the effectiveness of pledges in online fundraising.

Preferences for charitable giving in auctions can be modeled by assuming that bidders receive additional utility proportional to the revenue raised by an auctioneer. The theory of bidding in the presence of such preferences results in a very counterintuitive prediction which is that, in many cases, bidders having preferences for charitable giving does not lead to a substantial revenue advantage for an auctioneer. We test this theory and this prediction with a series of experiments. In one experiment we induce charitable preferences exactly as specified in the model to see if bidders respond to them as predicted. We find that they do. We then conduct a second experiment in which the revenue from the auctions is donated to actual charities to verify the robustness of the prediction when charitable preferences are generated by a more natural source and find again that the theoretical prediction holds: even strong charitable preferences do not result in substantial revenue increases to the auctioneer.

We explore the effect of fixed versus dynamic group membership on public good provision. In a novel experimental design, we modify the traditional voluntary contribution mechanism (VCM) by periodically replacing old members of a group with new members over time. Under this dynamic, overlapping generations matching protocol we find that average contributions experience significantly less decay over time relative to a traditional VCM environment with fixed group membership and a common termination date. These findings suggest that the traditional pattern of contribution and decay seen in many public goods experiments may not accurately reflect behavior in groups with changing membership, as is the case in many real-world environments.

We use a simple laboratory experiment to measure the effect on altruism of (i) whether the participants’ choices are presented verbally or non-verbally, and (ii) whether the participants have a large amount of loose change. We find strong evidence for the first effect and weaker evidence for the second. These effects may explain some of the variation in the average level of generosity found in different Dictator Game results.

This study examines fairness perceptions in ultimatum bargaining games with asymmetric payoffs, outside options, and different information states. Fairness perceptions were dependent on treatment conditions. Specifically, when proposers had higher chip values, dollar offers were lower than when responders had higher chip values. When responders had an outside option, offers were higher and were rejected less often than when proposers had an outside option. However, a given offer was rejected more often when responders had an outside option. Therefore, similar to the first mover advantage, the “advantaged” or “entitled” player received a higher monetary payoff than they would otherwise. When there was complete information about payoff amounts (payoff conversion rates and outside options), rejections occurred more often, and given offer amounts were rejected more often than when there was incomplete information. When there was incomplete information, offers were higher in the initial rounds than in the final rounds. These results suggest that proposers made offers strategically, making offers that would not be rejected, rather than out of a concern for fairness.

This paper reports three experiments with triadic or dyadic designs. The experiments include the moonlighting game in which first-mover actions can elicit positively or negatively reciprocal reactions from second movers. First movers can be motivated by trust in positive reciprocity or fear of negative reciprocity, in addition to unconditional other-regarding preferences. Second movers can be motivated by unconditional other-regarding preferences as well as positive or negative reciprocity. The experimental designs include control treatments that discriminate among actions with alternative motivations. Data from our three experiments and a fourth one are used to explore methodological questions, including the effects on behavioral hypothesis tests of within-subjects vs. across-subjects designs, single-blind vs. double-blind payoffs, random vs. dictator first-mover control treatments, and strategy responses vs. sequential play.

We examine how taxes impact charitable giving and how this relationship is affected by the degree of wasteful government spending. In our model, individuals make donations to charities knowing that the government collects a flat-rate tax on income (net of charitable donations) and redistributes part of the tax revenue. The rest of the tax revenue is wasted. The model predicts that a higher tax rate increases charitable donations. Surprisingly, the model shows that a higher degree of waste decreases donations (when the elasticity of marginal utility with respect to consumption is high enough). We test the model’s predictions using a laboratory experiment with actual donations to charities and find that the tax rate has an insignificant effect on giving. The degree of waste, however, has a large, negative and highly significant effect on giving.

This paper examines how image concerns affect the way giving behavior responds to social information. Subjects in the laboratory decide first whether they wish to donate part of their earnings to a charity, and then, conditional on opting in, decide how much to donate. They receive information on the size of a previous donation either before or after opting in, which allows one to examine the effect of the social information on the extensive and intensive margins of giving separately, and thus distinguish self-image concerns from potential alternative mechanisms. Information on a large previous donation caused subjects to opt out, but when shown only after opt-in, the same information caused subjects to increase donation amounts and did not lead to $0 donations. As further evidence of the influence of image concerns, the reaction to the social information was found to be correlated with a preference for quietly exiting a dictator game, and with scoring high on neuroticism. The results have implications for the inferences we draw about donor motives and welfare based on changes in giving in response to social information.

Several papers have documented that when subjects play with standard laboratory “endowments” they make less self-interested choices than when they use money they have either earned through a laboratory task or brought from outside the lab. In the context of a charitable giving experiment we decompose this into two common artifacts of the laboratory: the intangibility of money (or experimental currency units) promised on a computer screen relative to cash in hand, and the distinct treatment of random “windfall” gains relative to earned money. While both effects are found to be significant in non-parametric tests, the former effect, which has been neglected in previous studies, has a stronger impact on total donations, while the latter effect has a greater impact on the probability of donating. These results have clear implications for experimental design, and also suggest that the availability of more abstract payment methods may increase other-regarding behavior in the field.

We investigate the external validity of giving in the dictator game by using the misdirected letter technique in a within-subject design. First, subjects participated in standard dictator games (double blind) conducted in labs in two different studies. Second, after four to five weeks (study 1) or two years (study 2), we delivered prepared letters to the same subjects. The envelopes and the contents of the letters were designed to create the impression that they were misdirected by the mail delivery service. The letters contained 10 Euros (20 Swiss Francs in study 2) corresponding to the endowment of the in-lab experiments. We observe in both studies that subjects who showed other-regarding behavior in the lab returned the misdirected letters more often than subjects giving nothing, suggesting that in-lab behavior is related to behavior in the field.

This article replicates and “stress tests” a recent finding by Eckel and Grossman (2003) that matching subsidies generate substantially higher Charity Receipts than theoretically comparable rebate subsidies. In a first replication treatment, we show that most choices are consist with a “constant (gross) contribution” rule, suggesting that inattention to the subsidies’ differing net consequences may explain the higher revenues elicited with matching subsidies. Results of additional treatments suggest that (a) the charity dimension of the decision problems has little to do with the result, and (b) extra information regarding the net consequences of decisions reduces but does not eliminate the result.

Leadership mechanisms provide a potential means to mitigate social dilemmas, but empirical evidence on the success of such mechanisms is mixed. In this paper, we explore the institutional frame as a relevant factor for the effectiveness of leadership. We compare subjects’ behavior in public-goods experiments that are either framed positively (give-some game) or negatively (take-some game). We observe that leader and follower decisions are sensitive to the institutional frame. Leaders contribute less in the take-some game, and the correlation between leaders’ and followers’ contribution is weaker in the take-some game. Additionally, using a strategy method to elicit followers’ reactions at the individual level, we find evidence for the malleability of followers’ revealed cooperation types. Taken together, the leadership institution is found to be less efficient in the take- than in the give-frame, both in games that are played only once and repeatedly.

We conducted a laboratory experiment to study the effects of communication in a dictator game, while maintaining subjects’ anonymity. In the experiment, the recipient has an opportunity to state a payoff-irrelevant request for his/her share before the dictator dictates his/her offer. We found that the independence hypothesis that voice does not matter is rejected. In particular, if the request is for less than half of the pie, the dictator's offer increases as the recipient's request increases. Additionally, there is no dictator who is other-regarding and, at the same time, does not react to the recipient's request.

In an artefactual field experiment, we implemented a crowdfunding campaign for an institute’s summer party and compared donation and contribution framings. We found that the use of the word ‘donation’ generated higher revenue than the use of ‘contribution.’ While the individuals receiving the donation framing gave substantially larger amounts, those receiving the contribution framing responded more strongly to reward thresholds and suggestions. An additional survey experiment on MTurk indicated that the term ‘donation’ triggers more positive emotional responses and that emotions are highly correlated with giving. It appears that making a donation is perceived as a more voluntary act and is thus more successful at generating warm glow than making a contribution. We surmise that this extends to other funding mechanisms.

Are decisions in economics experiments distorted because the money subjects risk comes from the experimenter rather than their own pockets? There is some evidence that people receiving small, one time “windfall gains” have a higher marginal propensity to consume them, and when doing so, exhibit greater risk-seeking behaviour. This has been found in individual decision making experiments when anticipated wealth effects have been controlled, and labelled the “house money effect.” In public good experiments, house money effects could be driving the high levels of voluntary contributions commonly observed. This possibility is tested by comparing VCM contribution rates when subjects supply their own endowments with those when endowments are provided, while holding constant the distribution of promised earnings. No evidence of house money effects is found, suggesting that use of “free” initial money endowments does not distort subsequent contributions in VCM environments.

An influential result in the literature on charitable giving is that matching subsidies dominate rebate subsidies in raising funds. We investigate whether this result extends to “unit donation” schemes, a popular alternative form of soliciting donations. There, the donors’ choices are over the number of units of a charitable good to fund at a given unit price, rather than the amount of money to give. Comparing matches and rebates as well as simple discounts on the unit price, we find no evidence of dominance in our online experiment: the three subsidy types are equally effective overall. At a more disaggregated level, rebates lead to a higher likelihood of giving, while matching and discount subsidies lead to larger donations by donors. This suggests that charities using a unit donation scheme enjoy additional degrees of freedom in choosing a subsidy type. Rebates merit additional consideration if the primary goal is to attract donors.

Charitable donations provide positive externalities and can potentially be increased with an understanding of donor preferences. We obtain a uniquely comprehensive characterization of donation motives using an experiment that varies treatments between and within subjects. Donations are increasing in peers’ donations and past subjects’ donations. These and other results suggest a model of heterogeneous beliefs about the social norm for giving. Estimation of such a model reveals substantial heterogeneity in subjects’ beliefs about and adherence to the norm. A simple fundraising strategy increases donations by an estimated 30% by exploiting previously unstudied correlations between dimensions of donor preferences.

Experimental dictator games have been used to explore unselfish behaviour. Evidence is presented here, however, that subjects’ generosity can be reversed by allowing them to take a partner's money. Dictator game giving therefore does not reveal concern for consequences to others existing independently of the environment, as posited in rational choice theory. It may instead be an artefact of experimentation. Alternatively, evaluations of options depend on the composition of the choice set. Implications of these possibilities are explored for experimental methodology and charitable donations respectively. The data favour the artefact interpretation, suggesting that demand characteristics of experimental protocols merit investigation, and that economic analysis should not exclude context-specific social norms.

We present an experiment designed to separate the two commonplace explanations for behavior in ultimatum games—subjects’ concern for fairness versus the failure of subgame perfection as an equilibrium refinement. We employ a tournament structure of the bargaining interaction to eliminate the potential for fairness to influence behavior. Comparing the results of the tournament game with two control treatments affords us a clean test of subgame perfection as well as a measure fairness-induced play. We find after 10 iterations of play that about half of all non-subgame-perfect demands are due to fairness, and the rest to imperfect learning. However, as suggested by models of learning, we also confirm that the ultimatum game presents an especially difficult environment for learning subgame perfection.

We report the results of a field experiment conducted in conjunction with a mailed fundraising campaign of a nonprofit organization. The experiment is designed to compare the response of donors to subsidies in the form of matching amounts or rebated amounts. Matching subsidies are used by many corporations as an employee benefit; the US federal tax system encourages giving using a rebate subsidy by making donations tax deductible. The design includes a control group and two levels of subsidy of each type. Our main result is that matching subsidies result in larger total donations to charities than rebate subsidies, a result that is qualitatively similar to the lab findings. The estimated price elasticities for the matching subsidy are very similar to (and insignificantly different from) the lab experiments, while rebate subsidies lead to lower contributions in the field than in the lab. Since rebates in the field involve substantial lags and additional complications as compared with the “instant rebates” of the lab, this latter difference is not unexpected. The matching results are an important step in validating lab estimates of responsiveness to subsidies of charitable giving.