Essays on inequality, social preferences and consumer behavior[Inégalités, préférences sociales et comportement du consommateur]

This thesis studies ways in which inequality between and within groups affects consumer behaviors and welfare through social comparison effects. The objective is to provide a better understanding of a number of economic phenomena, namely: How to understand the extensive use of credit by lower income households in periods of stagnating real income growth? How do visible identities such as race or caste affect consumption choices, and can social hierarchies lead to poverty traps? Do luxury goods become more necessary when inequality rises, and what does such a phenomenon tell us about the social limits to growth? To that aim, the thesis incorporates important findings of behavioural economics, in particular on other-regarding preferences and subjective well-being, into theories of consumption and savings. Chapter 1 presents a model of relative consumption which accounts for comparison effects over time and across goods. The following chapters identify these effects using representative survey data and large datasets obtained via web-scrapping techniques. Chapter 2 looks at mortgage debt in the United States when households care about the relative size of their house. Chapters 3 and 4 study the social component of expenditures in India and its implication in terms of malnutrition using standard and structural estimation techniques.