PhD Thesis Defence – Johanne TROTIN

Johanne TROTIN
Economics

will publicly defend her PhD thesis entitled:
Essays on Pro-Environmental Consumption

Thesis supervised by Professor Patricia CRIFO and Professor Ivaylo PETEV

This thesis investigates the determinants of the adoption of pro-environmental behaviours, with a particular focus on consumption decisions. It combines laboratory experiments, field experiments, and theoretical modelling to analyse three mechanisms: risk preferences, social norms, and reputational concerns.

The first chapter examines the relationship between risk preferences and pro-environmental attitudes using a laboratory experiment. Risk preferences are measured through two lottery tasks, while attitudes are assessed through a questionnaire. The results show a positive and significant relationship between risk aversion and pro-environmental attitudes, as well as partial consistency in risk preferences, which is associated with greater consistency in pro-environmental attitudes.

The second chapter analyses a field experiment conducted in a student residence to assess the effect of providing personalised reports on energy consumption. Energy consumption decreased significantly among apartments that received these reports. However, the effect is highly heterogeneous and is mainly driven by the most pro-environmental households, which were already among the lowest energy consumers. The highest-consuming households show little response, raising questions regarding both effectiveness and welfare.

The third chapter develops a theoretical model in which pro-environmental behaviours are driven by environmental, financial, and reputational motivations. The model shows that social-image incentives may discourage low-cost conservation behaviours while encouraging costly but visible actions.

Overall, the thesis highlights the sometimes counterintuitive role played by social motivations.

Practical information:
Thursday, 8 October 2026 at 10:00 a.m.
ENSAE Paris – 5 avenue Henry Le Chatelier, 91120 Palaiseau
Amphithéâtre 200