Experimental Design Details
Participants take part in 10 sequences of a public goods game with dynamic contributions. At the beginning of each sequence, participants are divided into groups of three (random rematching across sequences), and each group member is given an endowment of 30 tokens. Each sequence consists of 6 rounds where, in each round, group members can decide how much of their remaining endowment to contribute to the Group Account. Any unassigned tokens at the end of the 6th round will remain in the members' Private Accounts. Group members receive their payoffs from the Group and Private Accounts only at the end of the 6th round.
Payoffs follow the standard VCM experiment: For every token remaining in a group member's Private Account, that member receives 1 token. For every token there is in the Group Account, each group member receives 0.4 tokens.
The main treatments vary on the information that group members receive at the end of each round of the sequence:
- In Treatment T (Time), participants are informed how many tokens have been accumulated in the Group Account at that point in the sequence.
- In Treatment M15 (Milestone-15), participants are informed whether the accumulated number of tokens in the Group Account has met the thresholds of 15, 30, 45, 60, 75, or 90.
- In Treatment M30 (Milestone-30), participants are informed whether the accumulated number of tokens in the Group Account has met the thresholds of 30, 60, or 90.
After the main task is completed, participants also complete a conditional cooperation task (similar to Fischbacher et al., 2001 and Fischbacher and Gächter, 2010). Participants will also be asked to complete a questionnaire eliciting their demographic characteristics, reasons for their decisions in the experiment, as well as decisions in a one-shot risk task (Gneezy and Potters, 1997).