“…We investigated direct reciprocity, generalized reciprocity and both phases or "components" of indirect reciprocity, which we will label "reputational giving" (35) and "rewarding reputation" (15). For simplicity, we refer to direct reciprocity, generalized reciprocity, reputational giving, and rewarding reputation as "four forms" of reciprocity, while recognizing that reputational giving and rewarding reputation, although conceptually distinct, are part of the same chain of giving (31). To isolate the effects of each of the four forms of reciprocity on prosociality while enabling them to be embedded with one another, we fully crossed the four forms with three levels or instantiations of each type, yielding a total of 81 conditions.…”