Framing change: behavioural insights to facilitate the transition to more sustainable dietary norms

Zamzow, Heidi (2025) Framing change: behavioural insights to facilitate the transition to more sustainable dietary norms. PhD thesis, London School of Economics and Political Science.

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Abstract

There is now a strong scientific consensus that a rapid and significant reduction in the consumption of animal products is needed in order to ensure a safe operating space for the planet. A multi-strategy approach incorporating behavioural interventions, along with market and regulatory mechanisms, will likely be required to change consumers’ eating habits. Insights from behavioural science can inform both interventions and communication strategies to help facilitate the transition to more sustainable dietary norms. Emerging research suggests using dynamic norms – social norm messages which emphasise how others are changing – may be effective in influencing attitudes and behaviours in a number of domains, including meat consumption. However, there have been only a few studies investigating social norm interventions to encourage sustainable diets. Moreover, the research on dynamic norms specifically is still nascent, with much to be learned about how they work and what could limit or improve their effectiveness. Evidence from behavioural science tells us that people may respond differently to information depending on how it is framed. Could there be ways to strategically frame changing diets to increase norm receptivity? In this thesis, I investigated this question across four empirical chapters which draw on literature relating to social norms, behavioural economics, and strategic communications. I began with a scoping review which assessed the extent and nature of the research on messaging interventions using social norms to encourage sustainable food choice. It revealed mixed findings on the effectiveness of such interventions, limited by significant knowledge gaps, methodological weaknesses, and heterogeneity of research designs. The next part of the thesis focussed on optimising communications by manipulating the framing of messages communicating changing dietary norms in the United Kingdom. In a series of online randomised controlled trials, I first examined the relationship between gain/loss framing of diet change and interest in adopting the new norm. Findings revealed no evidence of backfire effects, but that food neophobia could be a barrier to norm receptivity. I then tested the effect of framing shifting norms as being rooted in shared values and goals, exploring how different value frames resonated across demographic groups. Further, I investigated other factors which could influence openness to the emerging norm, including affect, response efficacy beliefs, and perceptions of who might benefit from the change. Overall, results suggested the effectiveness of value framing is limited and that, despite the new norm being seen as good for society and future generations, negative perceptions that one would not personally benefit inhibited interest in diet change. I applied the findings of these online studies in a field intervention exploring how messages emphasising the cobenefits of diet change might be used to complement other behavioural strategies to encourage sustainable dining at a university canteen. Whilst there was no evidence that the dynamic norm influenced behaviour, I did find that students’ selection of lower emission dishes increased significantly when more of these dishes were on offer. Taken together, results suggest there is a mismatch between current messaging around changing dietary norms versus predominant barriers and motivators in this domain: The emerging norm is often framed in ethical terms such as ‘healthy and sustainable’ and ‘benefitting society and future generations’, however consumers are more motivated by perceptions that plant-based foods are satisfying and that they themselves will benefit from the change. Further, they are more likely to choose plant-based offerings when they are plentiful and affordable. Yet many perceive these foods as unappealing and expensive, and plant-based items are still vastly underrepresented in the market. Thus both policies and communication strategies which circumvent these perceptual and structural barriers and align with existing hedonic and utilitarian drivers of food choice are more likely to be successful. This thesis contributes to the literature on dynamic norms by shedding light on how people in the UK perceive, process, and respond to information about changing diets, and the interplay between these factors and norm receptivity across different groups. Findings yield valuable insights for behavioural interventions and evidence to inform food policies and how they are communicated to help ensure they will be accepted and effective.

Item Type:	Thesis (PhD)
Additional Information:	© 2025 Heidi Zamzow
Library of Congress subject classification:	B Philosophy. Psychology. Religion > BF Psychology H Social Sciences > HF Commerce H Social Sciences > HM Sociology T Technology > TX Home economics
Sets:	Departments > Psychological and Behavioural Science
Supervisor:	Krpan, Dario and Gillespie, Alex
URI:	http://etheses.lse.ac.uk/id/eprint/4857

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