(a) Overall choice preferences (n=540) for relatively fair offers ($0.60, $0.40) compared with highly unfair offers ($0.90, $0.10) in the Self condition: participants exhibit strong preferences for the option to compensate in both fair and unfair trials; χ2=562.2, 4 df, P<0.001. However, preferences for retributive action become stronger when the offer is highly unfair; χ2=234, 3 df, P<0.001. (b) Unfair offers ($0.90, $0.10 split) reveal that participants have significantly stronger preferences for retributive behaviour (reverse option) when making decisions for another than they do for the self; χ2=20.2, 1 df, P<0.001, ϕ=0.13. (c) Fair offers (0.60, 0.40 split) reveal similar choice preferences for Self and Other conditions; all χ2s<1.16, all Ps>0.3; except for punish χ2=4.67, 1 df, P=0.03. ***P<0.001.