Rijkswaterstaat (the Directorate-General for Public Works and Water Management) wants to induce behavioural change in several areas. The circular economy is one example. A study examined whether consumers will make more sustainable choices if they have been complimented on their past actions or behaviour that were environmentally friendly or sustainable. This proved to be the case.

Why this experiment was conducted: additional incentive for sustainable behaviour
Behavioural change is tailor-made. Every change to sustainable behaviour requires a different approach. Encouraging second-hand purchases involves a different approach than promoting electric vehicle adoption. Even within an individual theme, such as waste separation, different approaches are needed: separating plastic is complicated, and separating food waste is dirty. Is it nevertheless possible to encourage people to make multiple sustainable choices? That is what the Behavioural Interventions Team at Rijkswaterstaat's Circular Economy & Waste department wanted to investigate.

Type of intervention: affirmation of sustainable identity
The team sought to determine whether people who already make a sustainable choice could be encouraged, through identity affirmation, to make another sustainable choice. Or specifically: if people choose a second-hand clothing voucher online, could they also be encouraged to choose a sustainable delivery option, based on the Change Mindset Model (Dijksterhuis and Van Baaren)? There were three groups:
• sustainable identity affirmation: in this group, the online text read 'Way to Go! Did you know that buying pre-owned clothes means fewer new clothes have to be made, and therefore less CO2 is emitted? Your choice of second-hand clothing voucher makes you a sustainable person who is doing good for the environment and the planet.'
• power identity affirmation, possibly with a reverse effect: in this group, the text read 'Way to Go! Did you know that by choosing pre-owned clothes, you can buy more designer and other clothing for the same amount of money? Second-hand clothes are often cheaper than new clothes. Your choice of second-hand clothing voucher makes you someone who gets the greatest value for their money.'
• control group: in this group, the text read 'Thank you for your choice. You now have the chance to win a voucher for second-hand clothes.

Method used: online experiment
Members of an online panel chose which reward to receive for their participation in the study in an online environment: a chance to win a voucher for new clothes or second-hand clothes from the same retailer. If participants chose the new clothes, they were thanked for their participation. If they chose second-hand clothing (680 respondents, about a quarter of all participants, did so), they were randomly shown one of the three texts. Next, they chose the delivery option: collect the voucher from the nearest pick-up point or have it delivered to their home by delivery service. The amount of CO2 was shown to inform them of the more sustainable option. An analysis was undertaken to determine in which group subjects were more likely to choose this sustainable option.

Result: compliment about sustainable behaviour works
The study shows that a sustainable identity affirmation afar selecting the second-hand clothing voucher leads to an increased likelihood that respondents will select the sustainable delivery option. 51% of respondents in this group opted for sustainable delivery, compared with a smaller proportion in the other groups (40% of respondents in the power condition and 32% in the control condition). So, there is evidence of a positive effect. The effect in the case of power identity confirmation is not significant. While the study does not show that the effect can be matched to a change in identity, it does show that complimenting sustainable behaviour has a direct effect on subsequent choices.

Impact: capable of wider application, but more research needed
More research is needed to properly understand how people make multiple sustainable choices successively and how the government can encourage this behaviour. Complimenting a sustainable choice in a sequence of choices seems to be a promising intervention, however.

Source: https://www.binnl.nl/home+-+en/knowledge/publications/bin+nl+publications/HandlerDownloadFiles.ashx?idnv=2719979