Reciprocity is a decisive behavioural rule resulting in successful co-operation or deterrence. In this paper, a dynamic model is proposed, where reciprocity is described by changes in altruistic (or malevolent) ties. Multiple steady states may exist in one of which there may be general...

Some researchers have attributed deviations from selfish behavior to fairness. Violations of fairness theories, however, are observed in experimental dictator games with transfer rates greater than 1 (a transfer of x from the dictator yields an income of tx for the beneficiary, where x tx): the...