Implementation Details ---------------------- This page describes how our lab implemented the procedures required by the official protocol for the RRR. It also describes and justifies any additions to or departures from that protocol. You can view the official protocl and the main project page for this RRR using these links: - Official Protocol: [https://osf.io/ypd78/][1] - Main RRR project page: [https://osf.io/scu2f/][2] ---------- #### Experimenters #### Experimenters are: Dr. Susann Fiedler, Head of the Gielen-Leyendecker Research Group on Cognitive Processes Underlying Economic Decision Making, Max Planck Institute for Research on Collective Goods Rima-Maria Rahal, MSc, Research Fellow, Max Planck Institute for Research on Collective Goods, & PhD Candidate, University of Amsterdam Minou Ghaffari, MSc, Research Fellow, Max Planck Institute for Research on Collective Goods Additional research assistants are advanced students of psychology, who are walked through and familiarized with the data collection protocol prior to data collection and test-run how to implement the protocol before the beginning of data collection. All research assistants are native speakers and are already experienced in these kinds of experiments. ---------- #### Setting/Lab/Equipment #### The testing environment at the Decision*Lab* at the Max Planck Institute for Research on Collective Goods provides 12 cubicles where participants are seated. Each cubicle is separated from the others with thick felt walls, so that participants cannot see each other. The equipment used are modern Dell Latitude laptop computers aquired in 2015, each equipped with a mouse for easy handling. ![DecisionLab][3] ---------- #### Sample, subjects, and randomization #### **Target sample size:** We plan to collect data from 168 participants. **Target sample demographics:** Participants will be invited to join the experiment via our participant pool managed through Orsee (Greiner, 2004). They will be compensated with a show-up fee of 5€ (approximately equivalent to 5 US dollars, adjusted by the cost difference of a McMeal at MacDonald's, transformed into € with the conversion rate on Aug 4, 2015 (1 US dollar=0.91€) and rounded to the full €). The money subjects have available for the one-shot public goods game will be 4€ (equivalent to 4 US dollars, see above). We will invite participants who are undergraduates of the University of Bonn and who just started studying and had no prior exposure to economic experiments, who are under the age of 35 (mean age 23-25 years), 45-60% females, German native speakers, and not psychology or economics students. **Minimum sample size after exclusions:** The minimum sample size after exclusions until which we will continue to collect data is 152. **Stopping rule(s):** We will stop data collection after 168 participants, and then exclude participants as specified in the protocol. If, after exclusions, we have fewer than 76 participants in either condition, we will schedule additional sessions until we have usable data from at least 76 participants (characteristics as above) in both conditions. **Randomization to conditions:** Participants will be randomly assigned to conditions by the provided Qualtrics Script. **Blinding to conditions:** Participants are verbally discouraged from speaking with each other during the experiment. They are told that all the information they need to complete the study will be provided via the computerized instructions, to ask questions only to the experimenter, and to do so quietly. Participants are seated in individual cubicles, and receive instructions via the computer, and they cannot see the other participants or their computer screens. **Exclusion rules:** Participants will be excluded if they do not complete all tasks or if the tasks are incorrectly administrated by the experimenter. Finally, we exclude participants who do not match the desired sample characteristics (i.e., psychology / economics students, have exposure to other experiments, not German native speakers, above the age of 35). Exclusion decisions will be made by someone blind to condition assignment. **Procedures for handling testing sessions for which the number of participants is not a multiple of 4:** As our testing room has 12 computer stations, we will schedule 15 participants. If all participants show up, three participants will be selected at random to participate in another unrelated experiment in a different lab at the testing site. If the number of participants who show up is not a multiple of 4, and not at least 8, we will again select participants at random for participation in another unrelated experiment, and send remaining people away without participating in any experiment, but with a show-up payment of 5€. ---------- #### Software/Code #### We will be using the provided materials, including the Qualtrics scripts, and we have verified that they work in our laboratory. ---------- #### Differences from the official protocol #### Since testing will be conducted with German native speakers, materials will be translated into German by the experimenters from Göttingen. To check that the materials are equivalent in meaning to the English originals, we will conduct a blind back-translation, and resolve any differences between the original and the back-translation with the other two German replication teams. [1]: https://osf.io/ypd78/ [2]: https://osf.io/scu2f/ [3]: http://jdmstudy.weebly.com/uploads/2/5/1/3/25139820/5569659_orig.png