Judgment and Decision Making,Vol.6.No.7,October 2011 Behind the veil of ignorance 606 important features unchanged.It is also important to note that the only nu I de mally given to subj ects were the cu d to each party The model of relative burden te we used the historic 30-vear average accord only graphically and the potentially confusing numerica ing to data from the U.S.Bureau of Economic Analysis were not p ed to subject GD growth I very unli 、of their choice after ould have been in riate instead we referred to ing their initial decision.At this point they could revise a Goldman Sachs Global Economics Paper (Wilson their choice if they so desired. Stupnytska,2007)for projections of Chin s GDP gre of this infon ble for 2.2 Recruitment procedures subjects,we used the average projected growth rate over his time frame,and we expre ed all numbers in terms er than rea Popula Caegie Mellon University in Pitts rgh,Pennsylvania cnmin Univer were re The most controversial assumption of the model is that the onnortunity to narticinate in a survey for a fixed cash the necessary eco omic sacrifice change payment of 15 Yuan(approximately US$2.25).Interested students were takent a computer lab wh they com ple eats were not and s ernment.Because our s cenario involved only two parties. we use 1%of joint GDP as the require to particular individuals.Furthermore.dividers between d sacrifice ith these figu omputers prevented between subjects were not i ed of the of the survey i ed to subiects (Figure 1) d linearly on thi bsolute dollar amount 15 minutes nd had no imnact That is.if located one third of on their standing in the class from which they were recruited the way from the left. the U.S.A (or Country/Farme the a Approximately half the Camegie Mellon University subjects ere recruite the s To reach implications of this division on per canita gDe for in as I the come)with sacrifice would then be immediately reflected tudent center.which is centrally located on campus and n the graph Ve that this is inte d only as requented by most students.a researcher was statione a laptop computers on no attempt to incorporate other features that are relevant to quivalent in purchasing power to the 15 Yuan given to such as how Ray's b ets).One minor difference in procedure at ha vas tha ere n llow for a hical elicitatic that d require multiple dependent inputs.our study simplifies ey and a subiects complied with this instruction the negotiation process to include only tw rties.Tha the inh erves as a proof of concept that the relative roles 3 Results of self-serving bias and cultural differences in faimess udg ents can be There were 292 Renmin University subjects and 429 h. ekey property gTiondcnmnaencgotia However, vealthier hut growing more slowly and the other oorer but growing more quickly.Even substantial devi- to the self-se ations in the parameters used would leave these features Judgment and Decision Making, Vol. 6, No. 7, October 2011 Behind the veil of ignorance 606 important features. We based the model on parameter estimates taken from maximally authoritative sources. Because the U.S. GDP growth is not expected to have dramatic long-term changes, we used the historic 30-year average accord￾ing to data from the U.S. Bureau of Economic Analysis. Because China’s GDP growth is very unlikely to remain at recent historic levels, such an assumption for China would have been inappropriate. Instead, we referred to a Goldman Sachs Global Economics Paper (Wilson & Stupnytska, 2007) for projections of China’s GDP growth over the next 30 years. To make the presentation and in￾terpretation of this information as simple as possible for subjects, we used the average projected growth rate over this time frame, and we expressed all numbers in terms of nominal rather than real GDP. Population growth rates for both countries were assumed to remain at their 2009 levels. The most controversial assumption of the model is that the necessary economic sacrifice required to combat cli￾mate change is 1% of world GDP. This estimate was taken from the Stern Review on the Economics of Cli￾mate Change (Stern, 2006) written for the British gov￾ernment. Because our scenario involved only two parties, we used 1% of joint GDP as the required sacrifice. With these figures, we calculated the absolute dollar sacrifice that must be made by the two parties. The slider presented to subjects (Figure 1) operated linearly on this absolute dollar amount. That is, if located one third of the way from the left, the U.S.A. (or Country/Farmer A) would bear two-thirds of the absolute dollar cost and China (or Country/Farmer B) would bear one-third. The implications of this division on per capita GDP (or in￾come) with sacrifice would then be immediately reflected in the graph. We reiterate that this model is intended only as a qual￾itatively appropriate simplification of the economics un￾derlying the problem. For example, our design does not attempt to incorporate other features that are relevant to fairness, such as how each party’s historic behavior has contributed to the problem (Rive et al., 2006). Also, to allow for a graphical elicitation procedure that does not require multiple dependent inputs, our study simplifies the negotiation process to include only two parties. That is, rather than attempting to capture all the inherent com￾plexity of multi-national climate change negotiations, our design serves as a proof of concept that the relative roles of self-serving bias and cultural differences in fairness judgments can be disentangled. The key property of international climate negotiations that is reflected in our design is the fact that one party is wealthier but growing more slowly and the other party is poorer but growing more quickly. Even substantial devi￾ations in the parameters used would leave these features unchanged. It is also important to note that the only nu￾merical details initially given to subjects were the cur￾rent per capita GDP (or income) and the growth rate for each party. The model of relative burdens was presented only graphically and the potentially confusing numerical details were not presented to subjects. To avoid over￾whelming them with information, we showed subjects numerical implications of their choices only after mak￾ing their initial decision. At this point they could revise their choice if they so desired. 2.2 Recruitment procedures The survey was conducted with subjects recruited from Renmin University of China in Beijing, China and from Carnegie Mellon University in Pittsburgh, Pennsylvania, U.S.A. The Renmin University subjects were recruited from large class lectures with a brief announcement of the opportunity to participate in a survey for a fixed cash payment of 15 Yuan (approximately US$2.25). Interested students were taken to a computer lab where they com￾pleted the survey online. Seats were not assigned and so it was clear to subjects that responses could not be traced to particular individuals. Furthermore, dividers between computers prevented communication between subjects. Subjects were not informed of the topic of the survey in advance, but were told that it would take approximately 15 minutes and had no impact on their standing in the class from which they were recruited. Approximately half the Carnegie Mellon University subjects were recruited by the same method. To reach the required number of subjects, however, it was neces￾sary to use an additional recruitment procedure. In the student center, which is centrally located on campus and frequented by most students, a researcher was stationed with several laptop computers. All Carnegie Mellon Uni￾versity subjects were given a cash payment of $5 (roughly equivalent in purchasing power to the 15 Yuan given to Chinese subjects). One minor difference in procedure at Carnegie Mellon University was that there were no di￾viders between computers. However, subjects were in￾structed not to communicate during the survey and all subjects complied with this instruction. 3 Results There were 292 Renmin University subjects and 429 Carnegie Mellon University subjects. However, 97 of the Carnegie Mellon University subjects were not U.S. citi￾zens. Because country of citizenship is directly relevant to the self-serving bias in these contexts, the main anal￾ysis is restricted to the 332 Carnegie Mellon University