Behavioural spillovers unpacked: estimating the side effects of social norm nudges

Fighting the climate crisis requires changing many aspects of our consumption habits. Previous studies show that a first climate-friendly action can lead to another. Does deciding not to eat meat increase our willingness to do more for the environment? Can encouraging vegetarianism alter this willingness? Using an online randomised control trial, we study the side effects of a social norm nudge promoting vegetarianism on environmental donations. We develop an experimental design to estimate these side effects and a utility maximisation framework to understand their mechanisms. Using an instrumental variable, we find that choosing not to eat meat increases donations to pro-environmental charities. We use machine learning to find that the social norm nudge crowds out donations from the population segment prone to choosing vegetarian food after seeing the nudge. However, the nudge led another group to make less carbon-intensive food choices without affecting their donations. Our results suggest that whilst social norm nudges are effective on specific population segments, they can also reduce the willingness of some groups to do more

Nudge plus: incorporating reflection into behavioural public policy

The authors of this paper outline a modified version of the behaviour change technique called ‘nudge plus’, which incorporates an element of reflection as part of the delivery of a nudge. Nudge plus builds on recent work advocating educative nudges and boosts. The authors claim that a hybrid nudge–think strategy can be a useful additional way to design pro-social interventions; combining a colour-coded ‘traffic lighting’ nudge with a salience-building ‘information plus’, for example, can increase the uptake of the nudge by agents, especially by those who might unconsciously ignore the visual cue implied by the colour coding of the nudge alone. Such a process is more plausible than the nudge-only strategies because combinations of nudges with reflective strategies are not only more liberty-preserving to the agent, but they can also generate stronger and persistent one-off effects. The authors suggest three key mechanisms of operationalising this nudge-plus: the plus could either come before and after (sequentially) or along with (simultaneous to) the nudge. Depending on when the ‘plus’ is administered with the nudge, it could embody various kinds of reflection; a plus that precedes a nudge, for instance, involves reflecting on the construct of the nudge or on the alternatives competing for availability to the decision-making agent. Finally, the authors compare the mechanistic scheme of the nudge-plus against that of the behavioural change tools that are currently available, namely classic nudges and boosts

The public have supported ‘hard’ policy measures, but will they still do so when the pandemic is over?

Britain, like other countries, has seen overwhelming public support for ‘hard’ policy measures during the pandemic. This runs counter to previous evidence that people prefer ‘soft’ interventions, such as nudges. Is this shift permanent? Could it apply to climate policy as well as the pandemic? Sanchayan Banerjee (LSE), Manu Savani (Brunel University London) and Ganga Shreedhar (LSE) look at the evidence so far

Trusting the trust game: an external validity analysis with a UK representative sample

Using a nationally representative sample of 1052 respondents from the United Kingdom, we systematically tested the associations between the experimental trust game and a range of popular self-reported measures for trust, such as the General Social Survey (GSS) and the Rosenberg scale for self-reported trust. We find that, in our UK representative sample, the experimental trust game significantly and positively predicts generalised self-reported trust in the GSS. This association is robust across a number of alternative empirical specifications, which account for multiple hypotheses corrections and control for other social preferences as measured by the dictator game and the public good game, as well as for a broad range of individual characteristics, such as gender, age, education, and personal income. We discuss how these results generalise to nationally representative samples from six other Organisation for Economic Co-operation and Development (OECD) countries (France, Germany, Italy, Korea, Slovenia, and the US)

It's time we put agency into Behavioural Public Policy

Promoting agency - people's ability to form intentions and to act on them freely - must become a primary objective for Behavioural Public Policy (BPP). Contemporary BPPs do not directly pursue this objective, which is problematic for many reasons. From an ethical perspective, goals like personal autonomy and individual freedom cannot be realised without nurturing citizens' agency. From an efficacy standpoint, BPPs that override agency - for example, by activating automatic psychological processes - leave citizens 'in the dark', incapable of internalising and owning the process of behaviour change. This may contribute to non-persistent treatment effects, compensatory negative spillovers or psychological reactance and backfiring effects. In this paper, we argue agency-enhancing BPPs can alleviate these ethical and efficacy limitations to longer-lasting and meaningful behaviour change. We set out philosophical arguments to help us understand and conceptualise agency. Then, we review three alternative agency-enhancing behavioural frameworks: (1) boosts to enhance people's competences to make better decisions; (2) debiasing to encourage people to reduce the tendency for automatic, impulsive responses; and (3) nudge+ to enable citizens to think alongside nudges and evaluate them transparently. Using a multi-dimensional framework, we highlight differences in their workings, which offer comparative insights and complementarities in their use. We discuss limitations of agency-enhancing BPPs and map out future research directions

What works best in promoting climate citizenship? A randomised, systematic evaluation of nudge, think, boost and nudge+

Nudges have been increasingly deployed to deliver climate policies in the last decade. Recent evidence shows nudges are hard to scale–up. So can we use nudges more effectively, or should we rely on other tools of behaviour change? We argue that reflective strategies can enhance nudges by encouraging agency and ownership in citizens. We test this by systematically comparing nudges to reflective interventions like thinks, boosts, and nudge+ over orders of low-carbon meals using an online experiment with 3,074 participants in the United Kingdom. We find all behavioural interventions increase intentions for climate-friendly diets, but encouraging reflection prior to nudging (“nudge+”) strengthens these treatment effects. There is no evidence of negative behavioural spillovers as measured by participants’ donations to pro-social charities. There is potential for reflective policies in promoting climate citizenship

Trusting the Trust Game: An External Validity Analysis with a UK Representative Sample

Using a nationally representative sample of 1052 respondents from the United Kingdom, we systematically tested the associations between the experimental trust game and a range of popular self-reported measures for trust, such as the General Social Survey (GSS) and the Rosenberg scale for self-reported trust. We find that, in our UK representative sample, the experimental trust game significantly and positively predicts generalised self-reported trust in the GSS. This association is robust across a number of alternative empirical specifications, which account for multiple hypotheses corrections and control for other social preferences as measured by the dictator game and the public good game, as well as for a broad range of individual characteristics, such as gender, age, education, and personal income. We discuss how these results generalise to nationally representative samples from six other Organisation for Economic Co-operation and Development (OECD) countries (France, Germany, Italy, Korea, Slovenia, and the US)