Homo reciprocans, or Reciprocal human, is the concept in some economic theories of humans as cooperative actors who are motivated by improving their environment. This concept stands in contrast to the idea of Homo economicus, which states the opposite theory that human beings are exclusively motivated by self-interest.
The homo reciprocans concept states that human being players interact with a propensity to cooperate. They will compromise in order to achieve a balance between what is best for them and what is best for the environment they are a part of. Homo reciprocans players, however, also are motivated by justification. If a second player is perceived as having done something wrong or insulting, the first player is willing to "take a hit," even with no foreseeable benefits, in order for the second player to suffer.
A common example of this interaction is the haggler and shopkeeper. If the haggler wants a deal and the shopkeeper wants a sale, the haggler must carefully choose a price for the shopkeeper to consider. The shopkeeper will consider a lower price (or a price in between) based on the benefit of selling a product. If the haggler's offer is a low-ball, which may be offensive to the shopkeeper, the shopkeeper may refuse simply on the grounds that he is offended, and will knowingly and purposely lose the sale.