International Choice Modelling Conference, International Choice Modelling Conference 2017

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Do social norms matter? Evidence from stated preference studies varying communicated social norm levels.
Katarzyna Zagórska, Mikołaj Czajkowski, Jacob LaRiviere, Natalia Letki, Nick Hanley

Last modified: 28 March 2017


We investigate whether social norm information influences respondents’ stated choices. This is tested in two large-scale empirical studies dealing with households’ preferences regarding changes in recycling schemes for a city and alterations to the national policy for labeling and control of genetically modified organisms (GMO) in food, commercial products, and pharmaceuticals. Our results indicate interesting social choice patters and put the existing theories in question.

In the first study we analyzed the impact of information on social norms on Poles' stated preferences regarding sorting waste. The results are based on a representative sample of 1,853 citizens of the three largest cities in Poland: Cracow, Warsaw and Bialystok. The data was collected via computer-assisted web interviewing technique in February 2014. The choice experiment consisted of 12 choice tasks each with four alternatives (three hypothetical new municipal recycling schemes and the status quo). The schemes were characterized by three attributes: number of in-home sorting categories, frequency of waste collection and fee. The treatments varied the social norm, i.e. used different sources of statistics and framing to communicate what is the overall share of households who sort.

In the second study we investigate the impact of information on social norms on consumers' stated preferences towards changes in the national policy of labeling and control of GMO. The data was collected in March to June 2016. We collected responses from a representative sample of 6,600 citizens of Poland. The hypothetical policies were described using four attributes representing market segments for which current EU regulations differ: GM food intended for direct consumption, food produced with the help of GMO but not containing any modified genes (e.g., processed foods, GMO used for fodder), pharmaceuticals and commercial products. Respondents decided between two variants of more/less restrictive policy (banning GM products from the market, obligatory labeling, voluntary labeling, and labeling ban) one of which was always the status quo level (current regulations require that all food products are labelled, labeling is voluntary for other products).

The information conditions varied in social perception of genetically modified products safety for health and environment. Earlier studies regarding the influence of social norms show mixed evidence. With respect to recycling, the literature suggests that individuals may display preferences for sorting because of the desire for a positive, environmental self- and external image. Other studies of the effects of the underlying norm-based motivation revealed that the importance of intrinsic motivation (moral norms) on recycling choices is more evident than that of extrinsic motivation (perceived social norms). Our results relate to this stream of literature and offer new insights by trying to influence the perceived behavior/attitudes of others.

In both studies we used a between-group design and created information treatments. We exogenously varied the information about descriptive social norms displayed to respondents immediately before elicitation of their preferences, and thus ensured that agents incorporate this information into their existing ex ante information sets when making choices for selected policies. For more comprehensive analysis of preferences we used follow-up questions about consumers’ current environmental behavior, attitudes and perceptions.

The information treatments differed in two dimensions. Firstly, in terms of the social norm level – we used low, medium and high social norm levels. Basing on different sources of information about recycling we created 7 information treatments, with the level of social norm varying from 6% to 72% of those who comply. In the GMO study we included 8 information treatments varying the social norm (common perception of GMO as safe for the environment or health) in the range of 5% to 75%. Each study also included the control group. Secondly, the social norms varied in terms of how local they were. The recycling study referred to the population of respondents’ city or the population of Poland, while the GMO study referred to the population of Poland of the population of the EU.

Our findings show that the influence of social norms varies for geographically-closer and –broader social norm. The effect of low and high social norm is asymmetric for individuals who currently do ‘a lot’ or ‘a little’ of recycling. In case of GMO, we find that respondents’ behavior is largely driven by existing threats concerns: information about higher level of social trust for bioengineering leads to stronger preferences for tightening the regulations, or at least increasing labeling requirements. Comparison of the two research leads to interesting conclusions with regard social information campaigns for public goods for with significantly different social perception of environmental benefits and risks - there is a rather common belief about positive external effects of sorting and a lot of uncertainties for GMO production. Overall, the results contribute to economic theory and the understanding of the role and way in which social norm information impacts preferences for public goods. They may also be applicable to policies aiming at provoking a particular behavioral response.


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