Family altruism and macroeconomic implications.

Summary Altruism is one of the explanations given by economists to account for intergenerational transfers within the family. Parents are interested in the well-being of their children and play on intergenerational solidarity in their favour. In macroeconomic models with overlapping generations, the instance where altruism develops is the dynasty. This thesis refocuses the study of intergenerational solidarities on the family. In contrast to the anonymous exchanges of markets, private transfers within families are characterized by non-anonymity stemming from the frequency of contacts and the small number of participants in these contacts. The inter-generational economy is made up of a sequence of families that follow one another over time. This conception of intergenerational transfers leads to a formulation of altruism different from Barro's dynastic altruism. Instead of the utility of the descendant, it is the income that he receives during the period of coexistence with his ascendant that enters the latter's utility function. In contrast to Barro's dynastic model, this conception of the family and the specification of altruism that is induced by it form the basis of the family model. There can be a multiplicity of stationary equilibria with altruism operating, including over-accumulation (chapter I). Pensions are neutral (chapter II) but public debt is not insofar as, unlike pensions, it modifies the family income taken into account by the altruistic head of household (chapter III). If one introduces the educational expenses incurred by heads of families in favour of their descendants, under certain conditions, there is an optimal level of pensions that maximizes the long-run growth rate of the economy.