Data from: The price of being seen to be just: an intention signalling strategy for indirect reciprocity

Cooperation among strangers is a marked characteristic of human sociality.
One prominent evolutionary explanation for this form of human cooperation
is indirect reciprocity, whereby each individual selectively helps people
with a ‘good’ reputation, but not those with a ‘bad’ reputation. Some
evolutionary analyses have underscored the importance of second-order
reputation information (the reputation of a current partner's
previous partner) for indirect reciprocity as it allows players to
discriminate justified ‘good’ defectors, who selectively deny giving help
to ‘bad’ partners, from unjustified ‘bad’ defectors. Nevertheless, it is
not clear whether people in fact make use of second-order information in
indirect reciprocity settings. As an alternative, we propose the intention
signalling strategy, whereby defectors are given the option to abandon a
resource as a means of expunging their ‘bad’ reputation. Our model
deviates from traditional modelling approaches in the indirect reciprocity
literature in a crucial way—we show that first-order information is
sufficient to maintain cooperation if players are given an option to
signal their intention. Importantly, our model is robust against invasion
by both unconditionally cooperative and uncooperative strategies, a first
step towards demonstrating its viability as an evolutionarily stable
strategy. Furthermore, in two behavioural experiments, when participants
were given the option to abandon a resource so as to mend a tarnished
reputation, participants not only spontaneously began to use this option,
they also interpreted others' use of this option as a signal of
cooperative intent.