Nobody needs such an illustration to observe that men are concerned sometimes merely with increasing their wealth and, at other times, with pursuing other objectives. Nor even that every man may be said to engage sometimes in one and at other times in another pursuit.

Nor does it make sense to call one of these behaviors “rational,” implying that behavior of another sort is less worthy; all ordinary behavior is essentially rational–the outcome of a deliberative process taking seconds or much longer. Behavior which is not rational is properly called “reflexive”; the plain fact is that reason, deliberation, the weighing of ends and means, etc. are not only the characterisitic of the processes determining the behavior of those we deem “normal” but play exactly the same role with respect to (at least near-) cretins and lunatics. We call that man a lunatic whose behavior (or pronouncement) is sufficiently outrageous or alarming , not because his reasoning powers are insufficiently able or because, even frequently, he reaches conclusions at variance with our own, with that of others, or even with that we perceive to be most in accordance with the “evidence” of experience. And such understanding must even be expanded to recognize that everyone, to one extent or another, will make choices, even with the utmost in (so-called) rational deliberation which will prove incapable or insufficient in achieving the desired outcome (not to mention the times that the “desired” outcome, technically successful, may prove–in hindsight–to be different–in satisfaction –than expected.

If any kernel of truth is to be extracted from the charade, it is that people are often influenced in their behavior by notions of equity, symmetry, and “fairness.” The world is chock-full of charlatans fully cognizant of that reality and well prepared to exploit such tendencies for their own particular–usually political–benefit.
Most of the “left” portion of the political spectrum and a fair portion of the ‘right” exist primarily to exploit this ever-present weakness and are, therefore, strenuous in their polemic appeals for “fairness” and “social justice,” while resisting powerfully any efforts to acquaint the broad masses with their socioeconomic interests and how they may be best realized.

Strong reciprocity seems a better explanation than reciprocal altruism for most human strategies. Here, cooperation is rewarded and defection is punished at cost to the punisher and thus is itself a cooperative behaviour.

So humans are not unique in this respect.