Tackling littering through targeted behavioural policy
By Denise Ong, Behaviour Change & Experience Design Lead, Kantar Public, Singapore and Rob McPhedran, Senior Director, Kantar Public, UK
In 1968, Singapore’s first Prime Minister Lee Kuan Yew launched the inaugural Keep Singapore Clean campaign.1 This campaign – as well as its successors – was unquestionably effective, as Singapore is now generally regarded as one of the world’s cleanest cities.
In present times, much of this reputation is attributable to Singapore’s field force of 55,000 cleaners responsible for maintaining the nation state’s public spaces. However, this solution has limited ongoing viability: the older profile of the resident cleaners – coupled with Singapore’s rapidly ageing population – presents a unique challenge for environmental policymakers.
Over the coming years, many cleaners will age out of their jobs, and there will not be enough new cleaners to cope with the workforce shrinkage.2 Therefore, now more than ever, there is a strong imperative for individual accountability and positive environmental behaviour change.
In this article, behavioural change experts Denise Ong and Rob McPhedran outline the learnings from a study recently conducted in Singapore, which highlight the need for a segmented approach, alongside population-level initiatives, to reduce public littering.
When behaviour doesn’t always align with values
Since the first Keep Singapore Clean campaign, the government has been encouraging citizens to do their part by disposing of rubbish responsibly.
A variety of interventions and initiatives have been introduced, spanning public and stakeholders’ communications and engagement campaigns; school-based programmes; fines and changes to infrastructure.
“For high standards of cleanliness to be sustainable in the long run, all of us must start playing our part… Each of us has a critical role in keeping our country clean, and this is a shared responsibility for all.”
– Mr Edward D’Silva (Chairman, Public Hygiene Council)
These initiatives have helped build a normative perception that keeping Singapore clean is the right thing to do. According to annual knowledge, attitude and perception surveys carried out by the National Environment Agency, Singaporeans generally claim to do the right thing (i.e. bin their rubbish) and that they should take responsibility for keeping public spaces clean.3
However, stated intentions and values do not always align with actual behaviour – a phenomenon commonly known as the value-action or intention-behaviour gap.4
“Internalising the right values from a young age is very important. As a society, I believe that our values [to do our part to keep Singapore clean] are there, but the practice is not always there.”
– Dr Tan Ern Ser (Associate Professor of Sociology, National University of Singapore)
The importance of context vs. intrinsic motivation
As with many behaviours, littering is heavily influenced by a mix of situational and contextual factors. In terms of external factors, whether or not an individual ends up littering, depends on:
Identifying which of these factors has the biggest impact on people’s littering behaviour – through real-world observations or trials – can be challenging, complex and expensive.
Further, different individuals may behave differently in the same setting.
In addition to context, people’s actions depend on their attitudes, beliefs, intrinsic and extrinsic motivations: for example, how harmful they think littering is to the environment; how they view the role of cleaners; and how concerned they are about social or financial sanctions.
Despite the influence of individual differences, existing interventions, policies, and campaigns – both in anti-littering behaviour specifically, and more broadly speaking – are largely implemented on a uniform, population-wide basis.
Such an approach does not account for individual heterogeneity, therefore limiting population-level effectiveness.
To address this challenge, in a recent littering behavioural study conducted in Singapore, our team used an innovative methodology to recommend a balance of national- and sub-population level interventions.
To understand and influence people’s littering behaviour, it is important first to understand the complex interplay between external factors (i.e. physical and social environment, situational context) and internal factors (e.g. knowledge, attitudes, beliefs).
As part of this study, our team incorporated two key components to facilitate this:
i Discrete Choice Experiments are a method from behavioural economics that is used to measure preferences and importance without direct questioning, thereby avoiding the value-action gap. They have been shown to predict certain behaviours with a high level of accuracy.6
ii COM-B (Capability, Opportunity, Motivation – Behaviour) is a model used to structure quantitative and qualitative insights to identify what needs to happen for an intervention to change a behaviour.7
An example of the hypothetical Discrete Choice Experiment scenarios can be seen here.
Please select the scenario in which you would be more likely to litter
The importance of context and psychological ownership over public spaces
Across the Singaporean population, a ‘full bin’ was the contextual factor that was most related to ‘littering’ in our experiment, while cleanliness of surroundings and distance to bin were secondary. This result suggests that infrastructure maintenance – that is, regular emptying of bins to ensure they do not fill up – could, in certain settings, be more important than general cleaning in discouraging littering.
Location is also crucial: the highest rate of littering was predicted in hawker centres (street food markets), while the lowest was in residential areas.
This result indicates that people are less willing to litter in spaces they consider their own, compared to communal settings where there is less psychological ownership.
Given that food outlets are considered one of the least clean public spaces by Singaporeans, the perception of hawker centres as ‘dirty’ or ‘wet’, is also likely to perpetuate littering behaviour by providing social proof that littering is acceptable in this setting.89
Therefore, for littering hotspots such as these, the maintenance of a clean environment (e.g. dry floors, tidy food tray return stations) alongside physical interventions to foster a sense of shared ownership, will be important to minimise littering behaviour.
A multi-pronged, targeted approach to tackling littering
Population-level interventions, such as those recommended above, are a necessary first step. However, they are unlikely to be effective in isolation due to individual differences in how and why people behave the way they do when it comes to littering. Therefore, we used a bespoke segmentation model to identify population segments with differing knowledge, attitudes, behaviours and demographics; and to determine the most important behavioural drivers and barriers to address for the different groups.
This model provided further evidence that a single policy, communications campaign or nudge is unlikely to work: there is a need for targeted strategies to reach the different segments.
Although some segments are responsive to ‘the stick’ (littering fines), the segment most likely to litter appeared unlikely to be moved by future negative incentives. Additionally, while triggering guilt may be effective for some in this segment, there is also a risk that this could ‘backfire’ – particularly among the more highly educated, who are more likely to rationalise their behaviour and/or become defensive.10
At its core, this segment feels disconnected from public spaces and from the issue of littering in general. Therefore, a sense of ownership over public spaces is needed to drive behaviour change among members of this segment, with reframing of littering to ensure the issue feels more personally relevant.
Building psychological ownership can be achieved in small ways, such as giving a nickname to a space or creating cues that suggest possession. Field experiments have shown that this approach can be effective in facilitating the stewardship of public goods.11
Source: 'Building psychological ownership can help governments preserve parks and public spaces', Tippie College of Business.
Ease of finding a bin is not a major factor for most; however, bin accessibility is an important driver for elderly segments. Therefore, it is important that bins are readily available, accessible, and visible in areas where older adults tend to congregate (such as residential public spaces and street food markets).
Environmental nudges, such as ‘green footprints’ that increase salience and (subconsciously) direct users to the nearest bin, have been shown to successfully reduce litter in public areas.12
Bespoke interventions: the way forward
Until now, the design of behavioural policy (for littering, and more generally) has predominantly focused on broad interventions and nudges. However, research has shown that such approaches can sometimes backfire for individuals who already engage in positive behaviours.13 Therefore, policymakers need to take citizens’ heterogeneity into account via more bespoke interventions wherever possible, delicately balancing precision with practicality.14
Despite the challenges inherent in this task, this much is clear: in environmental policy and beyond, one size truly does not fit all.
References and notes:
Keep Singapore Clean campaign. Singapore Infopedia.
Trailblazing into 2030: A truly clean city we can be proud of! Public Hygiene Council (2021)
Knowledge, Attitudes and Practices (KAP) Survey 2018, Keep SG Clean Report, National Environment Agency (2018)
Overcoming the ‘value‐action gap’ in environmental policy: Tensions between national policy and local experience. Blake, J. (1999)
Towards a cleaner Singapore: Sociological study on littering in Singapore. Straughan, P., et al. (2011)
Consistency between stated and revealed preferences: a discrete choice experiment and a behavioural experiment on vaccination behaviour compared. Lambooij, M., et al. (2015)
The behaviour change wheel: A new method for characterising and designing behaviour change interventions. Michie, S., van Stralen, M. and West, R. (2011)
Public Cleanliness Satisfaction Survey 2021. Singapore Management University (2021)
Using Behavioural Insights to Reduce Littering in the UK. Clean Up Britain (2016)
Communicating resourcefully: a natural field experiment on environmental framing and cognitive dissonance in going paperless. Gosnell, G.K. (2018)
Caring for the Commons: Using Psychological Ownership to Enhance Stewardship Behavior for Public Goods. Peck, J., et al. (2020)
Green Footprints: Case Study. Keep Britain Tidy (2015)
Nudges that hurt those already hurting – distributional and unintended effects of salience nudges. Thunström, L., Gilbert, B. and Jones. C. (2018)
Personalized nudging. Mills, S. (2020)
