Research

@article{lohmann2025fastslow,

title = {Nudging, Fast and Slow: Experimental Evidence from Food Choices under Time Pressure},

author = {Paul M. Lohmann and Elisabeth Gsottbauer and Christina Gravert and Lucia A. Reisch },

url = {https://link.springer.com/article/10.1007/s10640-025-01012-x},

year  = {2025},

date = {2025-06-26},

urldate = {2025-06-26},

journal = { Environmental and Resource Economics},

abstract = {Understanding when and why nudges work is crucial for designing interventions that consistently and reliably change behaviour. This paper explores the relationship between decision-making speed and the effectiveness of two nudges – carbon footprint labelling and menu repositioning – aimed at encouraging climate-friendly food choices. Using an incentivized online randomized controlled trial with a quasi-representative sample of British consumers (N = 3,052) ordering meals through an experimental food-delivery platform, we introduced a time-pressure mechanism to capture both fast and slow decision-making processes. Our findings suggest that menu repositioning is an effective tool for promoting climate-friendly choices when decisions are made quickly, though the effect fades when subjects have time to revise their choices. Carbon labels, in contrast, showed minimal impact overall but reduced emissions among highly educated and climate-conscious individuals when they made fast decisions. The results imply that choice architects should apply both interventions in contexts where consumers make fast decisions, such as digital platforms, canteens, or fast-food restaurants to help mitigate climate externalities. More broadly, our findings suggest that the available decision time in different contexts might at least partly explain differences in effect sizes found in previous studies of these nudges.},

keywords = {environment & climate, field experiments, nudging},

pubstate = {published},

tppubtype = {article}

}

@article{gravertfoodwaste2025,

title = {In-store food promotions increase sales as well as household food waste},

author = {Christina Gravert and Milica Mormann},

url = {https://www.nature.com/articles/s41598-025-01800-x},

doi = {https://doi.org/10.1038/s41598-025-01800-x},

year  = {2025},

date = {2025-05-26},

urldate = {2025-05-26},

journal = {Scientific Reports},

volume = {15},

number = {1},

pages = {1-10},

abstract = {Food waste is a serious problem affecting both global food security and climate change. Using a large-scale field experiment with data from 43,246 perishable vegetable purchases from eight supermarkets, we show that in-store offers lead to over-purchasing of food items and result in an increase in household food waste. Shoppers exposed to multi-unit offers (e.g., “2 for $5” or two-for-one pricing) purchase greater food quantities compared to those exposed to a single-unit discounts(e.g., “$2.50, regular price $2.89” or “50% off”). A follow-up survey shows that these additional items are subsequently less likely to be consumed, leading to an increase in household food waste. A complementary online survey provides further support for these results. Importantly, as a part of the field experiment, we test two strategies that can address in-store over-purchasing. Taken together, the current findings provide important insights into factors that increase over-purchasing and household food waste, as well as strategies that can help overcome them. We thus demonstrate how retailers can negatively, but also positively, impact important societal and environmental causes.},

keywords = {environment & climate, field experiments, nudging},

pubstate = {published},

tppubtype = {article}

}

@article{Gravert2024,

title = {Leveraging Field Experiments to Shape Environmental Policy },

author = {Christina Gravert},

url = {https://www.xn--nt-lka.dk/files/2024/article/Artikel_8.pdf},

year  = {2024},

date = {2024-10-04},

urldate = {2024-10-04},

journal = {Nationaløkonomisk Tidsskrift},

volume = {2024},

number = {8},

issue = {1},

abstract = {Deciding which environmental policies to implement is crucial for governments and essential for protecting our planet. Numerous policy questions from energy use, to meat consumption, to public transport usage require empirical answers. Ideally, policymakers would rely on causal evidence to design policies. However, in environmental policy this is rarely done. This paper advocates for policy experiments as a feasible and valuable approach to designing effective environmental policies exante. I address common objections to policy experiments, such as feasibility, lack of skills and possible objections of voters and show how they can be overcome. I use examples from my research to illustrate the potential of policy experiments in answering critical environmental questions and promoting evidence based policy making.},

keywords = {environment & climate, field experiments},

pubstate = {published},

tppubtype = {article}

}