Chapter 46 Reciprocity in Ultimatum and Dictator Games: An Introduction This chapter presents data based on treatment manipulations intended to affect subjects expectations about others behavior and degree of social isolation (anonymity) from the experimenter and others who might see the results holding constant subject anonymity with respect to each other .The standard economic game theoretic model predicts that the (conscious) reasoning process that applies to social exchange optimization in the self interest against other presumed self interested protagonists applies also to coalitional relations games against nature and other content specific decision problems. Of course this paradigm makes provision for cooperative behavior in repeat play interaction but such outcomes emerge out of reward and threat possibilities that channel the self interest into longer term betterment over time. According to game theory such behavior is strictly ruled out in any one shot game unless one postulates a taste (utility) for fairness a topic to which we shall return after introducing our experimental design and results.