The experiment will be conducted online and participants will be recruited using Amazon Mechanical Turk.
Subjects will be randomly assigned to groups of three. They vote on whether to take money designated for donation to a charity for their group (“Yes” or “No”). If, depending on the voting threshold, sufficiently many group members vote in favor of taking the money, the payoff is split equally among group members.
We test our hypotheses with different settings (one for each possible voting threshold) and assign subjects to exactly one of these settings (between-subject design):
Threshold 1: At least one “Yes” vote is required for transferring the money to the group. If all group members vote “No”, the money is donated.
Threshold 2: At least two “Yes” votes are required for transferring the money to the group. If at least two group members vote “No”, the money is donated.
Threshold 3: All group members need to vote “Yes” for transferring the money to the group. If at least one group member votes “No”, the money is donated.
In the first treatment, we are going to ask participants to vote unconditionally, i.e. independent of the other group members’ votes. These observations will be used to analyze the first hypothesis (on the impact of the voting threshold).
In the second treatment, we are going to split the group. Two randomly selected voters will decide unconditionally. The third group member will be asked for their vote conditional on the other two group members’ votes. The questions will be:
What would you vote for if none of your two group members voted “Yes”?
What would you vote for if exactly one of your two group members voted “Yes”?
What would you vote for if both of your two group members voted “Yes”?
Comparing the votes of the third group members who know that their vote is pivotal for the three thresholds allows us to test the second hypothesis (on the impact of guilt sharing). The reason is that the marginal (financial) benefit of voting “Yes” is the same in each treatment.
However, even when financial incentives are the same due to pivotality, there may still be different motivational factors including e.g. social conformity. To disentangle these factors, we will have two additional treatments. In these treatments, the actual votes of the group members are substituted by the votes of other participants.
In the third treatment, conditional voters are informed about the behavior of unconditional voters from the second treatment and the behavior of their group members. However, the votes of their group members are substituted with the votes of two random conditional voters from the second treatment.
In the fourth treatment, conditional voters are in the same situation as in the third treatment. However, they receive no information about the behavior of their actual group members.
Furthermore, we are also going to replicate the second treatment with a fifth treatment where we inform conditional voters about the behavior of unconditional voters from the second treatment.