We call the new treatment OSDG-IT, where IT stands for individual task. This treatment is an exact copy of the MP treatment except that the double-auction market is replaced by the individual task.
In the experiment participants will earn experimental currency units (ECU) which are converted to Euro at the end of the experiment as described in Brandts and Reidl (2018). The individual task will consist of 18 rounds in which participants will be able to earn ECU. Each of the 18 rounds will last for 95 seconds, which is the average length of a market round in the MP treatment. In each of these rounds participants will face the task of adjusting six sliders in the well-known slider task of Gill and Prowse (2012). The task is to position each slider at 50. Each correctly adjusted slider will yield ECU to the participants.
In the individual task, participants will be divided into two groups which differ regarding the compensation per correctly positioned slider. One group, low-earners, will receive 3.15 ECU and the other group, high-earners, will receive 24.74 ECU. These compensations are chosen such that when all sliders in all rounds are positioned correctly, the (rounded) total earnings are equal to the average earnings of respectively buyers and sellers (340 and 2672, respectively) in the MP treatment. Participants will be informed of their own compensation before the start of the slider task.
To maximize the likelihood that all participants position all sliders correctly there will be two unpaid trial rounds before the first round of the individual task. In the first trial round there will be no time limit. The reason for having this trial round is to let participants learn about the individual task. In the second trial round there will be a time limit of 95 seconds, just as in the subsequent paid rounds of the individual task. This second trial is meant to familiarize participants with the time pressure under which they will have to work in the paid rounds of the individual task. In addition, during the individual task, participants will receive a warning message when they did not position correctly all 6 sliders in a round.
Mirroring the MP treatment, before the start of the individual task, participants will be informed about the first six rounds of the OSDG, which take place immediately after the individual task is finished. Here participants are also informed that in the OSDG they will be paired with one other participant to play the OSDG and that this other participant will have either (a) the same individual task compensation, (b) a better individual task compensation, or (c) a worse individual task compensation. After the slider task and before the 6 rounds of the OSDG this information will be repeated together with a summary of the most important elements of the OSDG (in the same way as in the MP treatment).
The exact value of the paired participant’s slider task compensation will not be communicated to participants. This information condition is parallel to the one we used in the social dilemma game of the MP treatment, where participants were informed of whether they were paired with a buyer or a seller. In the double-auction market of the MP treatment earnings were private information. Nevertheless, from the market dynamics buyers and sellers may have been able to infer that buyers were in a worse earnings position than sellers.
The described matching of participants leads to three pairings: pairs of participants with low compensation (low-low), pairs of participants with high compensation (high-high), and pairs of participants with one participant having a low and the other participant having a high compensation (low-high). In total it is planned to collect data of 174 participants (approximately) equally divided across the three different pairings, giving a targeted 29 pairs per compensation pairing (low-low, high-high, low-high). As some participants may not be reaching the maximum earnings in the individual task we expect to get about 20-25 pairs with (close to) maximum income per compensation pairing.
In summary: we propose new treatments in the experimental, which will be compared with treatments that were run in the past. The treatments we ran in the past can be seen as "controls".