Experiment design

At the beginning of the experiment, all participants finish a hypothetical dictator game. The dic-tator game was introduced byKerschbamer(2015), and it provides a non-parametric approach to measure social preferences. The dictator game includes ten binary choices and requires the same workload of all participants. The ten choices are listed in AppendixA. This task not only creates an expectation of getting paid for finishing the task among participants, but also pro-vides information about social preferences for the analysis of the selection effect. Kerschbamer and Muller(2017) have used the same dictator game as the task to elicit social preferences and found that the decisions in the game are valid predictors for distributional attitudes and vot-ing behavior. The participants are informed that their final payoffs would not depend on their decisions in this task.

After finishing the dictator game, the experiment procedure is different for the recipients and the decision makers. The recipients are asked hypothetical questions about risk preferences and finish a short follow-up survey. The recipients are informed that their bonus payments depend on the decision outcomes of the decision makers. The decision makers follow the procedure illustrated in Figure1. There is no feedback about any decision outcome or payoff throughout the whole experiment, and all participants receive the payoffs after the experiment.

Each decision maker is rewarded 100 tokens for finishing the dictator game and is asked to play an investment game. Each token is worth US$ 0.02.² In the investment game (Gneezy and Potters,1997), a decision maker needs to choose how many tokens out of the 100 tokens, x, to invest in an asset that may return 2.5x with a chance of 1/3, or lose all invested tokens with a chance of 2/3. The expected payoff is 100+¹₆·x. Risk averse people would invest some tokens between 0 and a hundred, and the investment decisions of risk-neutral and risk-seeking people should be 100 tokens. The decision makers are told that the final payments depend on the random process of the lottery. Let the decision on behalf of oneself be notated asY_i^S, where the subscript i is a decision maker and the superscript S means that the decision is made on behalf of oneself.

After making the investment decisions, the decision makers are randomly allocated in two treatments;Non-voluntarytreatment andVoluntarytreatment. The proportion ofNon-voluntary treatment andVoluntarytreatment are one third (33%) and two thirds (67%), respectively. The unequal distribution between the two treatments is because the proportion of the decision mak-ers who would choose to volunteer is assumed to be 50%. Since the number of decision makmak-ers in Voluntarytreatment is around double the decision makers inNon-voluntary treatment, the number of decision makers in theNon-voluntarytreatment and the number of decision makers

2Due to the limit of budget, each token in the pilot part of the experiment is worth US$ 0.03. In the rest part of the experiment, each token is worth US$ 0.02. Participants in the pilot part of the experiment count around 25% of the total participants. The decisions do not differ between the pilot part and the rest part of the experiment, p=0.26 fort-test on the decisions on behalf of oneself and p=0.29 for thet-test on the decisions on behalf of others.

in the Voluntary treatment who would choose to volunteer would be similar. Each decision maker inNon-voluntarytreatment is asked to play the investment game on behalf of the recip-ient who is randomly matched with her. The decision maker is informed that the reciprecip-ient is rewarded 100 tokens for finishing the hypothetical dictator game. The decision maker is also told that no other questions would be relevant for her payoff after this decision. Let the decision made by the decision maker be notated asY_i^NV, where the subscriptiis a decision maker and the superscriptNV means that the decision is made in the institution where the decision maker is asked to decide for a recipient. Each decision maker inVoluntarytreatment is asked to make a choice between the following two alternatives: The first alternative is to make a decision in the investment game on behalf of the recipient randomly matched with her. The recipient would get an earning from the decision outcome, and the final earning of the decision maker would not be affected. The second alternative is to double the outcome of her own decision and the recipient would get zero. A decision maker who chooses to make the decision on behalf of a recipient, a volunteer, is told that no other questions would be relevant for her payoff after the decision. There is no such message for a decision maker who chooses the second alternative.

Let the decision made by a volunteer decision maker be notated asY_i^V, where the subscriptiis a decision maker and the superscriptV means that the decision is made in the institution where the decision maker volunteers to contribute and decide on behalf of the recipient. The willing-ness to volunteer is notated asV,V =1 if a decision maker is willing to volunteer, otherwise V =0. The notationV allows me to term some counterfactual outcomes later.

After making the volunteering decision, each volunteer decision maker decides on behalf of the recipient. Each non-volunteer decision maker is then told that she is re-matched with a different recipient, and she needs to make a decision on behalf of the re-matched recipient. The previously matched recipients with the non-volunteers do not get anything above the show-up fee. Before making the decision, the non-volunteer decision maker is told that this is the last question that is relevant for anyone’s payoff. Let the decision made by the non-volunteer be notated asY_i^NV, where the subscripti is a decision maker and the superscript NV means that the decision is made in the institution where the non-volunteer decision maker is asked to make the decision. It is assumed that only the institution matters for the decisions, not the treatment.

At the end of the experiment, all decision makers finish a short survey. The survey is the same as the one for all the recipients. This survey asks background information such as age, gender, education and what party they would choose if there was an election tomorrow. The follow-up survey can be found in AppendixB.6.

Finish task

Get twice outcome from decisionY_i^S No reward for the recipient

Notes: This figure describes the procedure for a decision maker. A decision maker can be assigned to theNon-voluntarytreatment with a chance of 33% and theVoluntarytreatment with a chance of 67%.

When choosing between Volunteer and Out, a decision maker in the Voluntary treatment is unaware of the subsequent decision making for a re-matched recipient. All the recipients finish the first step of hypothetical dictator game, and answer a couple of hypothetical questions about risk taking. The follow-up survey is the same for all the participants. All decision outcomes are revealed after the experiment is over.