Pre-print, Working paper: First, we present what is called the Theory of Psychological Preferences (altruism, rational reciprocity…) through, on one side, the list of axioms proposed by Sandbu (2008) for pure individual decisions and, on the other side, that of Segal and Sobel (2007) for strategical ones. Second, we characterize the potential relevance of such a theory to define a new "politicial economy" approach and we search to define the precise scope of this field of investigation in combining the micro'demands of the psychological preference theory with the standard macro'ones. Finally, we show that polycentered models seem to be the only framework within which individual psychological preference is an appropriate tool to study the collective impact of altruism, social loyalty, intrinsic reciprocity and so forth .