Data from: Human punishment is not primarily motivated by inequality

Previous theorizing about punishment has suggested that humans desire to
punish inequality per se. However, the research supporting such an
interpretation contains important methodological confounds. The main
objective of the current experiment was to remove those confounds in order
to test whether generating inequality per se is punished. Participants
were recruited from an online market to take part in a wealth-alteration
game with an ostensible second player. The participants were given an
option to deduct from the other player’s payment as punishment for their
behavior during the game. The results suggest that human punishment does
not appear to be motivated by inequality per se, as inequality that was
generated without inflicting costs on others was not reliably punished.
Instead, punishment seems to respond primarily to the infliction of costs,
with inequality only becoming relevant as a secondary input for punishment
decisions. The theoretical significance of this finding is discussed in
the context of its possible adaptive value.