Following your group or your morals? The in-group promotes immoral behavior while the out-group buffers against it

People learn by observing others, albeit not uniformly. Witnessing an immoral behavior causes observers to commit immoral actions, especially when the perpetrator is part of the in-group. Does conformist behavior hold when observing the out-group? We conducted three experiments (N=1,358) exploring how observing an (im)moral in-/out-group member changed decisions relating to justice: Punitive, selfish, or dishonest choices. Only immoral in-groups increased immoral actions, while the same immoral behavior from out-groups had no effect. In contrast, a compassionate or generous individual did not make people more moral, regardless of group membership. When there was a loophole to deny cheating, neither an immoral in-/out-group member changed dishonest behavior. Compared to observing an honest in-group member, people become more honest themselves after observing an honest out-group member, revealing that out-groups can enhance morality. Depending on the severity of the moral action, the in-group licenses immoral behavior while the out-group buffers against it.