Experimental Design Details
An experimental lab setting will be used for the research. Subjects will be recruited via the Sign-up System for paid research at the University of Warwick. The computerized experiment is programmed using o-tree. Participants attend the anonymous experiment using the computers in the Economics Lab at University of Warwick. There will be 20 participants in each session. //
At the beginning of the session, each participant will be randomly assigned to 1 of the 3 treatments: control, public apologies, private apologies. Regardless of the treatment, a participant will go through Section 1, Section 2, and a post-questionnaire. //
In section 1, participants will play a repeated public goods game for 16 periods with the same group members. In the control treatment, there are 2 stages in each period: in the decision stage, each participant needs to decide how many coins to contribute to the group project, estimate how many coins each other group member will contribute to the group project, and on a 7-point scale to what extent each other group member care about others; in the results stage, contribution of each group member is revealed to each participant; at the end of each period, each participant learn about their earnings from the public goods game and estimation in that period. //
In the two apologies treatments, the decision stage is the same as the control treatment; however, in the results stage, below the contribution results, participants are given the opportunity to send apology messages: in public apologies treatment, participants are asked whether they want to send a message saying "I am sorry" to the group, while in private apologies treatment, participants are asked whether they want to send a message saying "I am sorry" to each other group member respectively; there is a third stage in the two apologies treatments, where apology messages are shown: in public apologies, participants can see whether each of the group members chose to send a public apology, while in private apologies, participants can only see whether each of the other group members chose to send a private apology to him/her. Same as the control treatment, at the end of each period, each participant learn about their earnings from the public goods game and estimation in that period. //
After the instructions, there is 1 period of Practice Round for the participants to better understand the rules. //
In Section 2, participants in the same treatment will be randomly assigned to a new group of 4. The design of Section 2 follows the P-experiment in Fischbacher & Gächter (2010) while the parameters of the public goods game is the same as in Section 1. Each participant need to choose an unconditional contribution, fill out the conditional contribution table, then they will see the contribution of each group member in Section 2. Afterwards, they will see a summary of their earnings in each period in both Section 1 and Section 2. 4 periods in Section 1 will be randomly selected for final payment along with earnings in Section 2.//
Then participants will be asked to fill out a post-questionnaire via a Qualtrics link. The questionnaire includes questions on basic demographic information, open-ended question on their decisions and experiences in the experiment, scale questions to measure their risk-preference, social preferences, gulit and shame pronness, etc. Participants will be paid a separate fixed amount completion fee for completing the survey. //
After the survey, participants will see their total earnings (show-up fee+earnings from 4 random periods in section 1+earnings from section 2+questionnaire completion fee), be paid in cash and leave. //
Details of the experiment can be found in the attached instructions given to participants in the experiment and the post-questionnaire is also attached. //
We also plan to conduct three extra treatments in order to explore the mechanism. The only difference between the three extra treatments and the three main treatments will be in the extra treatments, in each period, participants in the same treatment will be randomly assigned to groups of 4 again, so they are no longer interacting with the same group members over the 16 periods. //
As a next step, we also plan to conduct experiments adding punishment to all the current treatments to investigate the interaction between apologies and punishment in public goods game.