Why to buy your darling flowers: On cooperation and exploitation

Trusting in someone's cooperation is often connected with the danger of being exploited. So it is important that signals are exchanged which make it probable enough that the potential partner is reliable. Such signals must be too expensive for partners who are planning to abuse the trust they are given but cheap enough for those who wish to initiate a long-term cooperation. In a game theoretical model, it is shown that such signals could consist of presents given before the partnership starts. These presents must be more expensive than the advantage of a one-period exploitation but smaller than the profit from a longterm partnership. In order to prevent that the receiver only collects presents, and that she is not interested in a firm partnership, these gifts should be of low value for her. Flowers are the prototype of such presents but usually not the only and not the most important signal of this kind. Nor is the partnership between men and women the only example of cooperative relations which are endangered by exploitation - but of all exploitation stories this one is most often narrated.