Tag: bounded rationality

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The economics of ‘greeniums’ in sustainable finance: doing good has a price

Sustainability has become one of the most pressing issues facing society. Patterns of human production and consumption have become unsustainable. On the environmental front, climate change, land-use change, biodiversity loss and depletion of natural resource are destabilising the Earth’s eco-system.

Furthermore, data on poverty, hunger and lack of healthcare show that many people live below minimum social standards. This has led to greater emphasis being placed on sustainable development: ‘development that meets the needs of the present without compromising the ability of future generations to meet their own needs’ (The Brundtland Report, 1987: Ch.2, para. 1).

The financial system has an important role to play in channelling capital in a more sustainable way. Since current models of finance do not consider the welfare of future generations in investment decisions, sustainable finance has been developed to analyse how investment and lending decisions can manage the trade-off inherent in sustainable development: sacrificing return today to enhance the welfare of future generations.

However, some commentators argue that such trade-offs are not required. They suggest that investors can ‘do well by doing good’. In this blog, I will use ‘green’ bonds (debt instruments which finance projects or activities with positive environmental and social impacts) to explain the economics underpinning sustainable finance and show that doing good has a price that sustainable investors need to be prepared to pay.

I will analyse why investors might not be doing so and point to changes which may be required to ensure financial markets channel capital in a way consistent with sustainable development.

The growth of sustainable finance

Sustainable finance has grown rapidly over the past decade as concerns about climate change have intensified. A significant element of this growth has been in global debt markets.

Figure 1 illustrates the rapid growth in the issuance of sustainability-linked debt instruments since 2012. While issuance fell in 2022 due to concerns about rising inflation and interest rates reducing the real return of fixed-income debt securities, it rebounded in 2023 and is on course for record levels in 2024. (Click here for a PowerPoint.)

Green bonds are an asset class within sustainability-linked debt. Such bonds focus on financing projects or activities with positive environmental and social impacts. They are typically classified as ‘use-of-proceeds’ or asset-linked bonds, meaning that the proceeds raised from their issuance are earmarked for green projects, such as renewable energy, clean transportation, and sustainable agriculture. Such bonds should be attractive to investors who want a financial return but also want to finance investments with a positive environmental and/or social impact.

One common complaint from commentators and investors is the ‘greenium’ – the price premium investors pay for green bonds over conventional ones. This premium reduces the borrowing costs of the issuers (the ‘counterparties’) compared to those of conventional counterparties. This produces a yield advantage for issuers of green bonds (price and yield have a negative relationship), reducing their borrowing costs compared to issuers of conventional bonds.

An analysis by Amundi in 2023 using data from Bloomberg estimated that the average difference in yield in developed markets was –2.2 basis points (–0.022 percentage points) and the average in emerging markets was –5.6 basis points (–0.056 percentage points). Commentators and investors suggest that the premium is a scarcity issue and once there are sufficient green bonds, the premium over non-sustainable bonds should disappear.

However, from an economics perspective, such interpretations of the greenium ignore some fundamentals of economic valuation and the incentives and penalties through which financial markets will help facilitate more sustainable development. Without the price premium, investors could buy sustainable debt at the same price as unsustainable debt, earn the same financial return (yield) but also achieve environmental and social benefits for future generations too. Re-read that sentence and if it sounds too good to be true, it’s because it is too good to be true.

‘There is no such thing as a free lunch’

In theory, markets are institutional arrangements where demand and supply decisions produce price signals which show where resources are used most productively. Financial markets involve the allocation of financial capital. Traditional economic models of finance ignore sustainability when appraising investment decisions around the allocation of capital. Consequently, such allocations do not tend to be consistent with sustainable development.

In contrast, economic models of sustainable finance do incorporate such impacts of investment decisions and they will be reflected in the valuation, and hence pricing, of financial instruments. Investors, responding to the pricing signals will reallocate capital in a more sustainable manner.

Let’s trace the process. In models of sustainable finance, financial instruments such as green bonds funding investments with positive environmental impacts (such as renewable energy) should be valued more, while instruments funding investments with negative environmental impacts (such as fossil fuels) should be valued less. The prices of the green bonds financing renewable energy projects should rise while the prices of conventional bonds financing fossil-fuel companies should fall.

As this happens, the yield on the green bonds falls, lowering the cost of capital for renewable-energy projects, while yields on the bonds financing fossil-fuel projects rise, ceteris paribus. As with any market, these differential prices act as signals as to where resources should be allocated. In this case, the signals should result in an allocation consistent with sustainable development.

The fundamental point in this economic valuation is that sustainable investors should accept a trade-off. They should pay a premium and receive a lower rate of financial return (yield) for green bonds compared to conventional ones. The difference in price (the greenium), and hence yield, represents the return investors are prepared to sacrifice to improve future generations’ welfare. Investors cannot expect to have the additional welfare benefit for future generations reflected in the return they receive today. That would be double counting. The benefit will accrue to future generations.

A neat way to trace the sacrifice sustainable investors are prepared to make in order to enhance the welfare of future generations is to plot the differences in yields between green bonds and their comparable conventional counterparts. The German government has issued a series of ‘twin’ bonds in recent years. These twins are identical in every respect (coupon, face value, credit risk) except that the proceeds from one will be used for ‘green’ projects only.

Figure 2 shows the difference in yields on a ‘green bond’ and its conventional counterpart, both maturing on 15/8/2050, between June 2021 and July 2024. The yield on the green bond is lower – on average about 2.2 basis points (0.022 percentage points) over the period. This represents the sacrifice in financial return that investors are prepared to trade off for higher environmental and social welfare in the future. (Click here for a PowerPoint.)

The yield spread fluctuates through time, reflecting changing perceptions of environmental concerns and hence the changing value that sustainable investors attach to future generations. The spread tends to widen when there are heightened environmental concerns and to narrow when such concerns are not in the news. For example, the spread on the twin German bonds reached a maximum of 0.045 percentage points in November 2021. This coincided with the 26th UN Climate Change Conference of the Parties (COP26) in Glasgow. The spread has narrowed significantly since early 2022 as rising interest rates and falling real rates of return on bonds in the near-term seem to have dominated investors’ concerns.

These data suggest that, rather than being too large, the greeniums are too small. The spreads suggest that markets in debt instruments do not seem to attach much value to future generations. The valuation, price and yield of green bonds are not significantly different from their conventional counterparts. This narrow gap indicates insufficient reward for better sustainability impact and little penalty for worse sustainability impact.

This pattern is repeated across financial markets and does not seem to be stimulating the necessary investment to achieve sustainable development. An estimate of the scale of the deficit in green financing is provided by Bloomberg NEF (2024). While global spending on the green energy transition reached $1.8 trillion in 2023, Bloomberg estimates that $4.8 trillion needs to be invested every year for the remainder of this decade if the world is to remain on track under the ‘net zero’ scenario. Investors do not seem to be prepared to accept the trade-off needed to provide the necessary funds.

Can financial markets deliver sustainable development?

Ultimately, the hope is that all financial instruments will be sustainable. In order to achieve that, access to finance would require all investors to incorporate the welfare of future generations in their investment decisions and accept sacrificing sufficient short-term financial return to ensure long-term sustainable development. Unfortunately, the pricing of green bonds suggests that investors are not prepared to accept the trade-off. This restricts the ability of financial markets to deliver an allocation of resources consistent with sustainable development.

There are several reasons why financial markets may not be valuing the welfare of future generations fully.

  • Bounded rationality means that it is difficult for sustainable investors to assign precise values to future and distant benefits.
  • There are no standardised sustainability metrics available. This produces great uncertainty in the valuation of future welfare.
  • Investors also exhibit cognitive biases, which means they may not value the welfare of future generations properly. These include present bias (favouring immediate rewards) and hyperbolic discounting (valuing the near future more than the distant future).
  • Economic models of financial valuation use discount rates to assess the value of future benefits. Higher discount rates reduce the perceived value of benefits occurring in the distant future. As a result, long-term impacts (such as environmental conservation) may be undervalued.
  • There may be large numbers of investors who are only interested in financial returns and so do not consider the welfare of future generations in their investment decisions.

Consequently, investors need to be educated about the extent of trade-offs required to achieve the necessary investments in sustainable development. Furthermore, practical models which better reflect the welfare of future generations in investment decisions need to be employed. However, challenges persist in fully accounting for future generations and it may need regulatory frameworks to provide appropriate incentives for effective sustainable investment.

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Questions

  1. Using demand and supply analysis, illustrate and explain the impact of sustainable investing on the markets for (i) green bonds and (ii) conventional bonds. Highlight how this should produce an allocation of finance capital consistent with sustainable development.
  2. Research the yields on the twin bonds issued by Germany since this blog was published. Can you identify any association between heightened environmental concerns and the spread between the ‘green’ and conventional bond?
  3. Analyse the issues which prevent financial markets from producing the pricing signals which produce an allocation of resources consistent with sustainable development.
  4. Research some potential regulatory policies which may provide appropriate incentives for sustainable investment.
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Black Friday vs the Rational Consumer

When building supply and demand models, the assumption is usually made that both producers and consumers act in a ‘rational’ way to achieve the best possible outcomes. As far as producers are concerned, this would mean attempting to maximise profit. As far as consumers are concerned, it would mean attempting to achieve the highest satisfaction (utility) from their limited budget. This involves a cost–benefit calculation, where people weigh up the costs and benefits of allocating their money between different goods and services.

For consumers to act rationally, the following assumptions are made:

  • Consumer choices are made independently. Their individual choices and preferences are not influenced by other people’s, nor do their choices and preferences impact on other people’s choices.
  • The consumer’s preferences are consistent and fixed.
  • Consumers have full information about the products available and alternatives to them.
  • Given the information they have and the preferences they hold, consumers will then make an optimal choice.

Black Friday can be seen as a perfect occasion for consumers to get their hands on a bargain. It is an opportunity to fulfil a rational need, for example if you were needing to replace a household appliance but were waiting until there was a good deal before committing to a purchase.

The assumption that people act rationally has been at the forefront of economic theory for decades. However, this has been questioned by the rise in behavioural economics. Rather than assuming that all individuals are ‘rational maximisers’ and conduct a cost–benefit analysis for every decision, behavioural economists mix psychology with economics by focusing on the human. As humans, we do not always behave rationally but, instead, we act under bounded rationality.

As economic agents, we make different decisions depending on our emotional state that differ from the ‘rational choice’ assumption. We are also influenced by our social networks and often make choices that provide us with immediate gratification. Given this, Black Friday can also be viewed as a great opportunity to fall prey to irrational and emotional shopping behaviours.

Black Friday originated in the USA and is the day after Thanksgiving. During this annual shopping holiday, retailers typically offer steep discounts to kick off the holiday season. The Black Friday shopping phenomenon is less than a decade old in the UK but it’s now an established part of the pre-Christmas retail calendar. Between 2010 and 2013, Black Friday gradually built up momentum in the UK. In 2014, Black Friday became the peak pre-Christmas online sales day and many online retailers haven’t looked back.

Arguably, from a behavioural economist’s perspective, the big problem with Black Friday is that all the reasons consumers possibly have to partake can be largely illusory. Consumers are bombarded with the promise of one-off deals, large discounts, scarce products, and an opportunity to get their holiday shopping done all at once. However, on Black Friday, our rational decision-making faculties are tested, just as stores are trying their hardest to maximise consumers’ mistakes.

There are many ‘behavioural traps’ that consumers often fall into. The following two are most likely to occur on Black Friday:

  • Scarcity and loss aversion. Shoppers may fear that they will miss out on the best sales deals available if they don’t buy it now. Retailers commonly spark consumers’ interest by highlighting limited stocks available for a limited time only, which raises the perceived value of these goods. This sense of scarcity can further trigger the need to buy now, increasing the ‘Fear of Missing Out’. Consumers therefore need to ask themselves if they are really missing out if they don’t buy it now? And is the discount worth spending the money today, or is there something else I should be spending it on or saving for?
  • Sunk cost fallacy. Once consumers have started to invest, they often struggle to close out investments that prove unprofitable. On Black Friday, customers have already made the initial investment of getting up early, driving to the shops, finding parking and waiting in a queue, before they have purchased anything. Therefore, they will be inclined to buy more than they initially went for. It is important therefore to think about each purchase in isolation.

This year, however, there is also the added complication of the rising cost of living. Whilst this may deter some consumers from unnecessary, impulse purchases, some consumers are using Black Friday as an opportunity to stock up on expected future purchases, hedging against likely price rises over the coming months.

It is thought that more consumers will be looking for a combination of high quality but low price to make sure their purchases are affordable and can last for a long time. According to PwC, many consumers have closely monitored their favourite brands in anticipation that big-ticket electronics, more pricey winter wear or Christmas stocking fillers will be discounted. Consumers are also in search of bargains more than ever given rising inflation. This would suggest a shift in attitude, meaning consumers will be more aware of what they cannot afford rather than giving in to emotional temptation brought on by Black Friday.

Retailers are fully aware of the cognitive biases that surround Black Friday and take full advantage of them. ‘Cyber Monday’ follows right after Black Friday, giving retailers an extra opportunity for them to keep those ‘urgent’ or ‘unmissable’ sales going and increase their revenues.

Black Friday is one of the biggest shopping days of the year. However, the way retailers approach it is growing increasingly mixed. Stores such as Amazon, Argos, Currys and John Lewis have started offering Black Friday deals much earlier in the month, leading some to refer to the event as ‘Black November’. Other stores, such as M&S and Next, didn’t take part at all this year.

Ultimately, Consumers can use insights from behavioural economics to empower them to make more rational decisions in such circumstances: ones that better align with their individual budgets. Nevertheless, the Black Friday sales mania can trigger our deepest emotional and cognitive responses that lead to unnecessary spending.

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Questions

  1. Discuss what is meant by the term ‘rational consumer’. Is it a useful generalisation about the way consumers behave?
  2. Discuss what is meant by the term ‘rational producer’. Is it a useful generalisation about the way firms behave?
  3. What is cost–benefit analysis? What is the procedure used in conducting a cost–benefit analysis?
  4. In addition to scarcity and loss aversion and the sunk cost fallacy, are there any other reasons why consumers may not always act rationally?
  5. Are people likely to be more ‘rational’ about online Black Friday purchases than in-store ones? Explain.
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Economists and the real world

Economists are often criticised for making inaccurate forecasts and for making false assumptions. Their analysis is frequently dismissed by politicians when it contradicts their own views.

But is this fair? Have economists responded to the realities of the global economy and to the behaviour of people, firms, institutions and government as they respond to economic circumstances? The answer is a qualified yes.

Behavioural economics is increasingly challenging the simple assumption that people are ‘rational’, in the sense that they maximise their self interest by weighing up the marginal costs and benefits of alternatives open to them. And macroeconomic models are evolving to take account of a range of drivers of global growth and the business cycle.

The linked article and podcast below look at the views of 2019 Nobel Prize-winning economist Esther Duflo. She has challenged some of the traditional assumptions of economics about the nature of rationality and what motivates people. But her work is still very much in the tradition of economists. She examines evidence and sees how people respond to incentives and then derives policy implications from the analysis.

Take the case of the mobility of labour. She examines why people who lose their jobs may not always move to a new one if it’s in a different town. Partly this is for financial reasons – moving is costly and housing may be more expensive where the new job is located. Partly, however, it is for reasons of identity. Many people are attached to where they currently live. They may be reluctant to leave family and friends and familiar surroundings and hope that a new job will turn up – even if it means a cut in wages. This is not irrational; it just means that people are driven by more than simply wages.

Duflo is doing what economists typically do – examining behaviour in the light of evidence. In her case, she is revisiting the concept of rationality to take account of evidence on what motivates people and the way they behave.

In the light of workers’ motivation, she considers the implications for the gains from trade. Is free trade policy necessarily desirable if people lose their jobs because of cheap imports from China and other developing countries where labour costs are low?

The answer is not a clear yes or no, as import-competing industries are only part of the story. If protectionist policies are pursued, other countries may retaliate with protectionist policies themselves. In such cases, people working in the export sector may lose their jobs.

She also looks at how people may respond to a rise or cut in tax rates. Again the answer is not clear cut and an examination of empirical evidence is necessary to devise appropriate policy. Not only is there an income and substitution effect from tax changes, but people are motivated to work by factors other than take-home pay. Likewise, firms are encouraged to invest by factors other than the simple post-tax profitability of investment.

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Questions

  1. In traditional ‘neoclassical’ economics, what is meant by ‘rationality’ in terms of (a) consumer behaviour; (b) producer behaviour?
  2. How might the concept of rationality be expanded to take into account a whole range of factors other than the direct costs and benefits of a decision?
  3. What is meant by bounded rationality?
  4. What would be the effect on workers’ willingness to work more or fewer hours as a result of a cut in the marginal income tax rate if (a) the income effect was greater than the substitution effect; (b) the substitution effect was greater than the income effect? Would your answers to (a) and (b) be the opposite in the case of a rise in the marginal income tax rate?
  5. Give some arguments that you consider to be legitimate for imposing controls on imports in (a) the short run; (b) the long run. How might you counter these arguments from a free-trade perspective?
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Evolving Economics

The linked article below, by Evan Davis, assesses the state of economics. He argues that economics has had some major successes over the years in providing a framework for understanding how economies function and how to increase incomes and well-being more generally.

Over the last few decades, economists have …had an influence over every aspect of our lives. …And during this era in which economists have reigned, the world has notched up some marked successes. The reduction in the proportion of human beings living in abject poverty over the last thirty years has been extraordinary.

With the development of concepts such as opportunity cost, the prisoners’ dilemma, comparative advantage and the paradox of thrift, economics has helped to shape the way policymakers perceive economic issues and policies.

These concepts are ‘threshold concepts’. Understanding and being able to relate and apply these core economic concepts helps you to ‘think like an economist’ and to relate the different parts of the subject to each other. Both Economics (10th edition) and Essentials of Economics (8th edition) examine 15 of these threshold concepts. Each time a threshold concept is used in the text, a ‘TC’ icon appears in the margin with the appropriate number. By locating them in this way, you can see their use in a variety of contexts.

But despite the insights provided by traditional economics into the various problems that society faces, the discipline of economics has faced criticism, especially since the financial crisis, which most economists did not foresee.

Even Davis identifies two major shortcomings of the discipline – both beginning with ‘C’. ‘One is complexity, the other is community.’

In terms of complexity, the criticism is that economic models are often based on simplistic assumptions, such as ‘rational maximising behaviour’. This might make it easier to express the models mathematically, but mathematical elegance does not necessarily translate into predictive accuracy. Such models do not capture the ‘messiness’ of the real world.

These models have a certain theoretical elegance but there is now an increasing sense that economies do not evolve along a well-defined mathematical path, but in a far more messy way. The individual players within the economy face radical uncertainty; they adapt and learn as they go; they watch what everybody else does. The economy stumbles along in a process of slow discovery, full of feedback loops.

As far as ‘community’ is concerned, people do not just act as self-interested individuals. Their actions are often governed by how other people behave and also by how their own actions will affect other people, such as family, friends, colleagues or society more generally.

And the same applies to firms. They will be influenced by various other firms, such as competitors, trend setters and suppliers and also by a range of stakeholders – not just shareholders, but also workers, customers, local communities, etc. A firm’s aim is thus unlikely to be simple short-term profit maximisation.

And this broader set of interests translates into policy. The neoliberal free-market, laissez-faire approach to policy is challenged by the desire to take account of broader questions of equity, community and social justice. However privately efficient a free market is, it does not take account of the full social and environmental costs and benefits of firms’ and consumers’ actions or a fair distribution of income and wealth.

It would be wrong, however, to say that economics has not responded to these complexities and concerns. The analysis of externalities, income distribution, incentives, herd behaviour, uncertainty, speculation, cumulative causation and institutional values and biases are increasingly embedded in the economics curriculum and in economic research. What is more, behavioural economics is becoming increasingly mainstream in examining the behaviour of consumers, workers, firms and government. We have tried to reflect these developments in successive editions of our four textbooks.

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Questions

  1. Write a brief defence of traditional economic analysis (i.e. that based on the assumption of ‘rational economic behaviour’).
  2. What are the shortcomings of traditional economic analysis?
  3. What is meant by ‘behavioural economics’ and how does it address the concerns raised in Evan Davis’ article?
  4. How is herd behaviour relevant to explaining macroeconomic fluctuations?
  5. Identify various stakeholder groups of an energy company. What influence are they likely to have on the company’s behaviour?
  6. In an era of social media, web-based information and e-commerce, why might it be necessary to rethink the concept of GDP and its measurement?
  7. What is meant by an efficient stock market? Why may the stock market not be efficient?
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Nudging for better or for worse

One of the key developments in economics in recent years has been the growing influence of behavioural economics. We considered some of the insights of behavioural economics in a blog in 2016 (A nudge in the right direction?). As the post stated, ‘Behavioural economists study how people’s buying, selling and other behaviour responds to various incentives and social situations. They don’t accept the simplistic notion that people are always rational maximisers.’ The post quoted from a Livemint article (see first linked article below):

According to behavioural economists, the human brain neither has the time nor the ability to process all the information involved in decision making, as assumed by the rational model.

Instead, people use heuristics. A heuristic technique is any approach to problem-solving, such as deciding what to buy, which is practical and sufficient for the purpose, but not necessarily optimal. For example, people may resort to making the best guess, or to drawing on past experiences of similar choices that turned out to be good or bad. On other accasions, when people are likely to face similar choices in the future, they resort to trial and error. They try a product. If they like it, they buy it again; if not, they don’t.

On other occasions, they may use various rules of thumb: buying what their friends do, or buying products on offer or buying trusted brands. These rules of thumb can lead to estimates that are reasonably close to the utility people will actually get and can save on time and effort. However, they sometimes lead to systematic and predictable misjudgements about the likelihood of certain events occurring.

In traditional models of consumer choice, individuals aim to maximise their utility when choosing between goods, or bundles of goods. The context in which the choices are offered is not considered.

Yet, in real life, we see that context is important; people will often make different choices when they are presented, or framed, in different ways. For example, people will buy more of a good when it is flagged up as a special offer than they would if there is no mention of an offer, even though the price is the same.

The recognition that framing is important to choices has led to the development of nudge theory. Indeed, it underpins many marketing techniques. These seek to persuade people to make a particular choice by framing it in an optimistic way or presenting it in a way that makes it easy to decide.

Governments too use nudge theory. In the UK, the Coalition government (2010–15) established the Behavioural Insights Team (BIT) (also unofficially known as the Nudge Unit) in the Cabinet Office in 2010. A major objective of this team is to use ideas from behavioural economics to design policies that enable people to make better choices for themselves.

The podcast linked below, looks at the use of nudge theory. The presenter, Mary Ann Sieghart looks at how we are being encouraged to change our behaviour. She also looks at the work of UCL’s Love Lab which researches the way we make decisions. As the programme notes state:

Mary Ann is grilled in UCL’s Love Lab to find out how she makes decisions; she finds taking the pound signs off the menu in a restaurant encourages her spend more and adding adjectives to the food really makes it taste better.

Walking through the Nudge Unit, she hears how powerful a tiny tweak on a form or text can get be, from getting people back to work to creating a more diverse police force. Popular with the political left and right, it has been embraced around the world; from Guatemala to Rwanda, Singapore to India it is used to reduce energy consumption, encourage organ donation, combat corruption and even stop civil wars.

But the podcast also looks at some of the darker sides of nudging. Just as we can be nudged into doing things in our interests, so too we can be nudged to do things that are not so. Politicians and businesses may seek to manipulate people to get them to behave in ways that suit the government or the business, rather than the electorate or the consumer. The dark arts of persuasion are also something that behavioural economists study.

The articles below explore some of the areas where nudge theory is used to devise policy to influence our behaviour – for good or bad.

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Questions

  1. Explain what are meant by ‘bounded rationality’ and ‘heuristics’.
  2. How may populist politicians use nudge theory in their campaigning?
  3. Give some examples from your own behaviour of decisions made using rules of thumb.
  4. Should we abandon models based on the assumption of rational maximising behaviour (e.g. attempts to maximise consumer surplus or to maximise profit)?
  5. Find out some other examples of how people might be nudged to behave in ways that are in their own interest or that of society.
  6. How might we be nudged into using less plastic?
  7. How might people be nudged to eat more healthily or to give up smoking?
  8. To what extent can financial incentives, such as taxes, fines, grants or subsidies be regarded as nudging? Explain.
  9. Would you advise all GP surgeries and hospital outpatient departments to text reminders to people about appointments? What should such reminders say? Explain.