Data from: Local competition promotes hurtful behavior towards unknown others

Humans frequently cooperate to achieve benefits unattainable through
selfish behavior. Punishment of free-riders is key for sustaining
cooperation, but also costly, raising questions about the origins of such
behavior. Some evolutionary models suggest that individuals may be willing
to hurt unknown others in competitive environments. However, empirical
evidence about the effect of the scale of competition on strategies
involving hurtful behavior in human groups, such as spite, retaliation for
hurting, and punishment of free-riders, is missing. Using a laboratory
experiment, we manipulate the scale of competition to investigate its
influence on hurtful and helpful behaviors between unknown humans in an
indirect reciprocity game. We observe distinct behavioral patterns between
local and global competition. When competition is local and thus confined
to take place within isolated groups, we find frequent hurting as an
expression of spite and retaliation. In contrast, when competition extends
globally across several groups, hurting is used for the punishment of
free-riders primarily, whereas helping behavior is rewarded, which
together promotes cooperation. Thus, while isolated competition fosters
inefficient, antisocial behavior, global competition encourages
prosociality and cooperation.