Also, of noted interest, the authors mention that chimpanzees display no "other regarding preferences". Thus, it seems a closest evolutionary cousins have not developed an extensive notion of sharing.
In neuroeconomics, a typical paradigm involving the allocation of resources is used to study decision making. The experiment goes you and another individual are to split a sum of money. One individual is told to decide which percentage of x$ you get and he gets. You then get to accept the offer or decide that neither of you receives anything. The results of this study were if people felt they were being cheated they would forgo any sort of payment to spite the other particpant. Logically this is not in their best interest. Regardless of what is offered you might as well accept and be better off than you were before. This studies were done in fMRI and scans showed that "unfair" offers elicited heightened activity in the anterior insula, as well as the dorsolateral prefrontal cortex.Activity of the insula, known for its involvement in emotion suggests that decisions, are not purely cognitive in origin. This experiments illustrates the notion that people are not rational maximizers, and sometimes "reason doesn't matter".
Link to Nature article
Link to neuroeconomics paper