Thinking through norms can make them more effective. Experimental evidence on reflective climate policies in the UK

Adopting low-carbon diets is important to meet our climate goals. Prior experimental evidence suggests green nudges help people adopt such diets, more so when encouraged to think through them. In this paper, we re-evaluate this role of reflection in a “social norm” nudge to promote intentions for climate-friendly diets in the United Kingdom. Using 5,555 English respondents, we find that the social norm nudge increases meal order intentions for low-carbon diets versus the control condition. Asking people to reveal their personal dietary norms after exposing them to these social norms (“lower-order nudge+”) does not produce any measurable change compared to the nudge. However, when people are subsequently encouraged to think and pledge to climate-friendly diets (“higher-order nudge+”), the effectiveness of the social norm nudge increases by 90% or more.