Table 1: Overview of Experiments 1 and 2 results. The AR/FR column presents the ratio between the corresponding results in the alternating and the fixed role experiment. The last two columns present Wilcoxon rank sum tests of the null hypothesis that the result distribution is the same in the two experiments.

Treatment Altern. roles Fixed roles AR/FR
Wilcoxon
Mean SE Mean SE

Baseline A investments 3.22 0.16 3.07 0.16 1.05 207.5 0.385
B returns 2.00 0.16 3.54 0.26 0.56 142.5 0.079
B ret. (prop.) 0.09 0.01 0.16 0.01 0.56 137.0 0.059
CI 0.50 0.00 0.51 0.00 0.98 319.0 0.118

No incentive A investments 5.07 0.23 3.47 0.12 1.46 174.0 0.029
B returns 6.87 0.42 3.24 0.16 2.12 196.0 0.003
B ret. (prop.) 0.24 0.01 0.14 0.01 1.71 189.0 0.006
CI 0.63 0.01 0.54 0.00 1.17 396.0 0.000

Fixed inc. A investments 3.61 0.21 2.36 0.11 1.53 170.0 0.040
B returns 3.75 0.30 2.47 0.15 1.52 142.0 0.232
B ret. (prop.) 0.17 0.01 0.10 0.01 1.70 150.0 0.153
CI 0.54 0.01 0.52 0.00 1.04 264.0 0.319

A incentive A investments 5.21 0.21 3.96 0.14 1.32 174.5 0.028
B returns 6.42 0.45 5.27 0.27 1.22 147.0 0.180
B ret. (prop.) 0.23 0.01 0.21 0.01 1.10 134.0 0.333
CI 0.60 0.01 0.56 0.01 1.07 365.0 0.002

B incentive A investments 4.50 0.18 3.68 0.14 1.22 154.0 0.121
B returns 4.75 0.28 4.07 0.19 1.17 141.5 0.238
B ret. (prop.) 0.19 0.01 0.18 0.01 1.06 130.0 0.387
CI 0.58 0.01 0.55 0.00 1.05 307.0 0.071