This paper investigates whether people are conditional reciprocators in an investment game experiment, in the sense that the more they are trusted, the more they reciprocate. The results show that the majority of participants are conditional reciprocators but that they can be classified into three types: (1) exploitative reciprocators who do not reciprocate and exploit trust; (2) egoistic reciprocators who neither exploit nor reward trust; and (3) generous reciprocators who reward trusting behavior.