The problem with this hypothesis is that it requires inequality: mutualism sustains cooperation only when cooperators gain higher returns than others.
Countless studies have shown that humans are not blind altruists, cooperating regardless of what others do, but rather are conditional cooperators: we prefer to cooperate only when we are reasonably certain that others will too.
According to him, we are by nature cooperators, although at first we cooperate only with members of our own family.
To give an illustrative but somewhat unrealistic example, assume that cooperators, and only cooperators, always know of some new secret place to rendezvous if they face too much free-riding in their current groups.
This should in turn amplify their chances of spreading and ultimately result in the decimation of cooperators (indeed, only between 20 30% survive).
In the gifted group, a significant amount of cooperators shifted only if their group failed to earn a bonus (Z = −2.490, p<0.05) and free-riders stayed regardless of success or failure (Z = 2.495, p<0.05 ZZ = 1.969, p<0.05).
Toriumi et al. [8] revealed that SNSs have similar properties to public goods games, but they correspond to the dual part of the meta-norms game [20] because SNSs seem to lack a means of punishing non-cooperators and only give (psychological) rewards to cooperators.
The premium on coordinated responses is illustrative of positive frequency-dependent selection, ensuring bistability in a well-mixed population (a final outcome of either cooperators-only or defectors-only, dependent on initial frequency of cooperators).
Consequently, partners intermix with cooperators but not cheaters.
Thus, partners grow and pile over cooperators but not cheaters.
