Essays on population dynamics and social outcomes

(eng) The essays included in this work deal with three very different examples of the interplay between population dynamics and social outcomes. Population dynamics are intended in multiple dimensions: as population growth, ageing, and with respect to the composition between locals and immigrants. The social outcomes take different qualifications according to the specific issue dealt with in each essay, broadly concerning the resource-allocation that a society as a whole turns out to implement: the agreements on crop-distribution and management of natural resources; the allocation choice between consumption, health-care expenditure, and environmental investment; the settlement of education regimes and the quality of public education. In the first essay the focus is on an episode of the past: the experience of the Easter Island civilization which after centuries of sustained population growth, suddenly collapsed when the overexploitation of resources completely spoiled the island's ecosystem. A micro-funded model is provided where the collapse does not derive from mechanistic law of motions but can be spurred by a population race among clans to share the crop, when groups bargain to share crops and their military power is increasing in their relative size. Factors that could account for the different destinies of similar primitive society are discussed. In the second essay we address the implications of population ageing in a political-economic model with endogenous longevity and voting over the expenditure on two important determinants of human health: health-care spending and environmental maintenance. As corroborated by empirical evidence, the relative support for such items is not neutral to age, as environmental care find larger support among the young and vice versa. The outcome is then compared with the one resulting from a social planner approach where also future unborn generations are taken into account. Several channels through which the two solutions differ are highlighted. Finally, in the third essay it is analysed the impact of low-skilled immigration in the hosting country education system, with respect to the combination of funding-sources, expenditures per pupil in public and in private schools, and the choice of enrolling children into private rather than public school according to the skill-type of parents. Education regimes are obtained as equilibria of a micro-funded model where households choose fertility and schooling, while the expenditure in public education result from the locals' vote. No exogenous culturally-based difference is imposed. It is found that as low-skilled immigration increases, forms of segregation in education becomes more likely, with children from highly skilled households attending private schools.