Understanding the Role of Social Norms in Recycling Behavior: A New York City Study funded by EREF

Almost every day, we're reminded to recycle: from separating paper and plastics at home, to spotting recycling bins in public areas, to reading about environmental initiatives online. The Environmental Research & Education Foundation (EREF) has even published tips for more eco-friendly travel with a focus on recycling.

The practice of recycling – the day-to-day decisions and actions consumers take, like correctly sorting waste and cleaning recyclables – can be tedious or just downright confusing. While the recycling infrastructure, which encompasses collection, transportation, Material Recovery Facilities (MRFs), secondary processing, and re-manufacturing by product manufacturers plays a pivotal role, it's the consumer that plays the most critical role in the quality and efficiency of the recycling stream. When recyclable materials are mixed with non-recyclables, it diminishes the overall effectiveness and value of the recyclables. This is particularly prevalent in areas where the recycling infrastructure might not be as robust as in places with a well-established system.

Recycling rates for multifamily buildings often lag behind those of single-family homes based on data from the Environmental Protection Agency. The disparity usually stems from structural issues such as the need for recycling bins, inconvenient access, or insufficient signage in addition to residents' will or knowledge. Once these structural hurdles are addressed, attitudes and behaviors become vital in enhancing recycling rates.  A recent EREF-funded study has provided valuable insights into this pressing issue, exploring the efficacy of social norms in influencing these consumer recycling decisions and actions.

The study was spearheaded by Elizabeth Hewitt, Ph.D., an Associate Professor at Stonybrook University. With substantial funding provided by EREF, the study devised various interventions in two NYC-area properties to influence recycling behaviors. The primary goal was to evaluate how peer pressure and educational strategies could affect residents' recycling habits and to identify any significant differences in the effectiveness of these approaches.

Hewitt's research team selected two multifamily buildings in New York City for their study, designated as “North” and “South,” applying different interventions in each. The South Building was subjected to a competition-based intervention where residents were provided with weekly graphic notices that "graded" their recycling performance against that of the North Building. The graphics were posted in every trash room on every floor. This method drew on strategies proven successful in the energy sector, where creating a competitive environment has been shown to motivate individuals to alter their behavior. The notices included data that reflected the building's recycling activities from the previous week or from the most recent sampling event, fostering a sense of competition among residents.

Conversely, the North Building experienced a non-comparative feedback intervention. Here, residents also received weekly updates on their recycling efforts, posted in the trash rooms, but these updates were specific to their building and did not include any comparative data. The feedback was coupled with positive reinforcement and educational content about recycling, aiming to encourage residents through information and affirmation rather than competition.

Both interventions were designed to leverage social norms to promote recycling behavior, but they differed fundamentally in their approach to motivation. The South Building's intervention hinged on peer pressure and competition, while the North Building's strategy relied on education and individual feedback. This distinction was central to the study's aim to compare the effectiveness of different social norm-based interventions in influencing sustainable recycling practices.

In the South Building, residents recycled 4% more during the challenge. That number significantly increased post-treatment, resulting in a 19% increase in recycling rates. The North Building saw a similar increase of 3.2% during the intervention, but that number fell to a decrease in recycling of 4.2% following the intervention. These percentages reflect the specific outcomes of the interventions, with the competitive approach in the South Building yielding a more pronounced and lasting increase in recycling activity among residents. The study's findings suggest the potential impact of social norm-based interventions, particularly competitive ones, on promoting sustainable behaviors in urban residential settings.

Further, the results show that contamination rates (the inclusion of non-recyclable materials in the recycling stream) increased in both buildings over the study period. Initially, contamination ranged from 10% in the South Building to 18% in the North Building. During the interventions, this contamination increased to approximately 20-25% in both buildings. This increase in contamination could suggest that while residents may have been motivated to recycle more by the interventions, they were not necessarily recycling the correct materials. It appears that the efforts to increase recycling participation may have inadvertently led to more non-recyclable materials being included in the recycling stream, thus raising the contamination rates. Increased motivation without increased education resulted in decreased accuracy; this is called the intention-behavior gap.

These findings, while mixed, lean towards the positive, revealing that the young, well-educated, and high-income residents of these buildings are environmentally conscious and proactive in their recycling efforts. However, the study did not find overwhelming evidence that social norms were a strong motivator for behavior change, despite many residents acknowledging the interventions and finding them helpful.

This research illustrates the complex interplay between environmental intentions and actual behavior, highlighting the potential of targeted interventions to enhance recycling rates. However, it also points to the need for continued efforts to educate residents on proper recycling practices to reduce contamination rates. As urban populations grow and the strain on waste management systems increases, studies like this become ever more vital in guiding our approach to sustainable living. Through the invaluable support of organizations like EREF and the dedication of researchers like Dr. Hewitt, there is a clearer path to navigate these challenges and refine the approach. Collaboration between research institutions, funding bodies, and the general populace is essential in ensuring that recycling efforts are sustained and optimized for a more circular economy.

Dr. Hewitt presented an EREF Science Session: Unwrapping Recycling in NYC for the Holidays discussing her research and results. Check EREF’s website for more information on this report and many other EREF-funded sustainability projects.

[1] https://archive.epa.gov/region4/rcra/mgtoolkit/web/pdf/multi.pdf