<P> One - to - many and many - to - one reciprocity often lies somewhere between direct reciprocal arrangements and generalized reciprocity . Informal clubs in which the hosting arrangements circulate among members are examples of the one - to - many variety . Bridal showers are examples of the many - to - one variety . So are barn raising practices in some frontier communities . All of these are similar to direct reciprocity, since the beneficiaries are identified as such in each case, and contributors know exactly what they can expect in return . But because membership in the group changes, and needs for new meetings or marriages or barns are not always predictable, these cases differ significantly from precisely defined one - to - one cases . </P> <P> Generalized reciprocity is even less precise . Here donors operate within a large network of social transactions largely unknown to each other, and without expectations about getting specific benefits in return--other than, perhaps, the sort of social insurance provided by the continuance of the network itself . Recipients may not know the donors, and may not themselves be able to make a return in - kind to that network, but perhaps feel obligated to make a return to a similar network . Blood banks and food banks are examples . But in fact any stable social structure in which there is a division of labor will involve a system of reciprocal exchanges of this generalized sort, as a way of sustaining social norms . </P> <P> All of these patterns of reciprocity, along with related ideas such as gratitude, have been central to social and political philosophy from Plato onward . These philosophical discussions concern the ways in which patterns and norms of reciprocity might have a role in theories of justice, stable and productive social systems, healthy personal relationships, and ideals for human social life generally . </P> <Table> <Tr> <Td> </Td> <Td> This section possibly contains original research . Please improve it by verifying the claims made and adding inline citations . Statements consisting only of original research should be removed . (December 2012) (Learn how and when to remove this template message) </Td> </Tr> </Table>

According to the law of reciprocity as it relates to organizational politics